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Spring全部笔记_韩顺平springboot笔记

作者：小惠珠哦 | 2024-08-16 06:08:11

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韩顺平springboot笔记

文章目录

1、Spring

1.1、简介

spring官网： https://spring.io/projects/spring-framework#overview

官方下载： https://repo.spring.io/release/org/springframework/spring/

GitHub： https://github.com/spring-projects/spring-framework

Spring Web MVC： spring-webmvc最新版

<!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>5.2.7.RELEASE</version>
</dependency>
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<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.2.7.RELEASE</version>
</dependency>

1.2、优点

Spring是一个开源的免费框架（容器）！
Spring是一个轻量级的非入侵式的框架
控制反转（IOC），面向切面编程（AOP）！
支持事务的处理，对框架整合的支持

开源免费容器，轻量级非侵入式，控制反转，面向切面，支持事务，支持框架整合

Spring是一个轻量级的控制反转(IOC)和面向切面(AOP)编程的框架

1.3、组成

1.4、扩展

现代化的java开发 -> 基于Spring的开发

2、IOC理论推导

传统的调用

UserDao

package dao;
public interface UserDao {
	void getUser();
}

   
   
   
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UserDaoImp

package dao;
public class UserDaoImpl implements UserDao{
	public void getUser() {
		System.out.println("默认获取用户数据");	
	}
}

   
   
   
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UserSevice

package Service;
public interface UserService {
	void getUser();
}

   
   
   
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UserServiceImp

package Service;
import dao.UserDao;
import dao.UserDaoImpl;
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public class UserServiceImpl implements UserService{
UserDao userDao = new UserDaoImpl();
public void getUser(){
userDao.getUser();
}
}

测试

package holle0;
import Service.UserService;
import Service.UserServiceImpl;
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public class MyTest0 {
public static void main(String[] args) {
// 用户实际调用的是业务层，dao层他们不需要接触
UserService userService = new UserServiceImpl();
userService.getUser();
}
}

在我们之前的业务中，用户的需求可能会影响我们原来的代码，我们需要根据用户的需求去修改原代码！如果程序代码量十分大，修改一次的成本代价十分昂贵！

改良：我们使用一个Set接口实现。已经发生了革命性的变化！

//在Service层的实现类(UserServiceImpl)增加一个Set()方法
//利用set动态实现值的注入！
private UserDao userDao;
public void setUserDao(UserDao userDao){
    this.userDao = userDao;
}

 
 
 
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set() 方法实际上是动态改变了 UserDao userDao 的初始化部分（new UserDaoImpl()）

测试中加上

((UserServiceImpl)userService).setUserDao(new UserDaoImpl());

 
 
 
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之前，程序是主动创建对象！控制权在程序猿手上！
使用了set注入后，程序不再具有主动性，而是变成了被动的接受对象！（主动权在客户手上）

本质上解决了问题，程序员不用再去管理对象的创建

系统的耦合性大大降低，可以更专注在业务的实现上

这是IOC（控制反转）的原型，反转(理解)：主动权交给了用户

IOC本质

3、HolleSpring

在父模块中导入jar包

<!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
<dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-webmvc</artifactId>
	<version>5.2.7.RELEASE</version>
</dependency>

 
 
 
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pojo的Hello.java

package pojo;
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public class Hello {

<span class="token keyword">private</span> String str<span class="token punctuation">;</span>

<span class="token keyword">public</span> String <span class="token function">getStr</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token keyword">return</span> str<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setStr</span><span class="token punctuation">(</span>String str<span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token keyword">this</span><span class="token punctuation">.</span>str <span class="token operator">=</span> str<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> String <span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token keyword">return</span> <span class="token string">"Holle [str="</span> <span class="token operator">+</span> str <span class="token operator">+</span> <span class="token string">"]"</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
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}

在resource里面的xml配置

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd">
<span class="token comment">&lt;!--在Spring中创建对象，在Spring这些都称为bean
	类型 变量名 = new 类型();
	Holle holle = new Holle();
	
	bean = 对象(holle)
	id = 变量名(holle)
	class = new的对象(new Holle();)
	property 相当于给对象中的属性设值,让str="Spring"
--&gt;</span>

<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>bean</span> <span class="token attr-name">id</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>hello<span class="token punctuation">"</span></span> <span class="token attr-name">class</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>pojo.Hello<span class="token punctuation">"</span></span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>str<span class="token punctuation">"</span></span> <span class="token attr-name">value</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>Spring<span class="token punctuation">"</span></span><span class="token punctuation">/&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>bean</span><span class="token punctuation">&gt;</span></span>
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</beans>

测试类MyTest

package holle1;
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import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import pojo.Hello;

public class MyTest {

<span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token comment">//获取Spring的上下文对象</span>
	ApplicationContext context <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ClassPathXmlApplicationContext</span><span class="token punctuation">(</span><span class="token string">"beans.xml"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
	<span class="token comment">//我们的对象下能在都在spring·中管理了，我们要使用，直接取出来就可以了</span>
	Hello holle <span class="token operator">=</span> <span class="token punctuation">(</span>Hello<span class="token punctuation">)</span> context<span class="token punctuation">.</span><span class="token function">getBean</span><span class="token punctuation">(</span><span class="token string">"hello"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
	System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>holle<span class="token punctuation">.</span><span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
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}

核心用set注入，所以必须要有下面的se()方法

//Hello类
public void setStr(String str) {
		this.str = str;
	}

 
 
 
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思考：

IOC：对象由Spring 来创建，管理，装配！

弹幕评论里面的理解：

原来这套程序是：你写好菜单买好菜，客人来了自己把菜炒好招待，就相当于你请人吃饭
现在这套程序是：你告诉楼下餐厅，你要哪些菜，客人来的时候，餐厅把做好的你需要的菜送上来
IoC：炒菜这件事，不再由你自己来做，而是委托给了第三方__餐厅来做

此时的区别就是，如果我还需要做其他的菜，我不需要自己搞菜谱买材料再做好，而是告诉餐厅，我要什么菜，什么时候要，你做好送来

在前面第一个module试试引入Spring

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd">
<span class="token operator">&lt;</span>bean id<span class="token operator">=</span><span class="token string">"userDaomSql"</span> <span class="token keyword">class</span><span class="token operator">=</span><span class="token string">"dao.UserDaoMysqlImpl"</span><span class="token operator">&gt;</span><span class="token operator">&lt;</span><span class="token operator">/</span>bean<span class="token operator">&gt;</span>

<span class="token operator">&lt;</span>bean id<span class="token operator">=</span><span class="token string">"userServiceImpl"</span> <span class="token keyword">class</span><span class="token operator">=</span><span class="token string">"service.UserServiceImp"</span><span class="token operator">&gt;</span>
    <span class="token operator">&lt;</span><span class="token operator">!</span><span class="token operator">--</span>ref引用spring中已经创建很好的对象<span class="token operator">--</span><span class="token operator">&gt;</span>
    <span class="token operator">&lt;</span><span class="token operator">!</span><span class="token operator">--</span>value是一个具体的值<span class="token punctuation">,</span>基本数据类型<span class="token operator">--</span><span class="token operator">&gt;</span>
    <span class="token operator">&lt;</span>property name<span class="token operator">=</span><span class="token string">"userDao"</span> ref<span class="token operator">=</span><span class="token string">"userDaomSql"</span><span class="token operator">/</span><span class="token operator">&gt;</span>
<span class="token operator">&lt;</span><span class="token operator">/</span>bean<span class="token operator">&gt;</span>
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</beans>

第一个module改良后测试

package holle0;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import service.UserServiceImpl;
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public class MyTest0 {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext(“beans.xml”);
UserServiceImpl userServiceImpl = (UserServiceImpl) context.getBean(“userServiceImpl”);
userServiceImpl.getUser();
}
}

总结：

所有的类都要装配的beans.xml 里面；

所有的bean 都要通过容器去取；

容器里面取得的bean，拿出来就是一个对象，用对象调用方法即可；

4、IOC创建对象的方式

使用无参构造创建对象，默认。
使用有参构造（如下）

下标赋值

index指的是有参构造中参数的下标，下标从0开始;

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd">
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>bean</span> <span class="token attr-name">id</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>user<span class="token punctuation">"</span></span> <span class="token attr-name">class</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>pojo.User<span class="token punctuation">"</span></span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>constructor-arg</span> <span class="token attr-name">index</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>0<span class="token punctuation">"</span></span> <span class="token attr-name">value</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>chen<span class="token punctuation">"</span></span><span class="token punctuation">/&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>bean</span><span class="token punctuation">&gt;</span></span>
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</beans>

类型赋值（不建议使用）

<bean id="user" class="pojo.User">
    <constructor-arg type="java.lang.String" value="kuang"/>
</bean>

 
 
 
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直接通过参数名（掌握）

<bean id="user" class="pojo.User">
    <constructor-arg name="name" value="kuang"></constructor-arg>
</bean>
<!-- 比如参数名是name，则有name="具体值" -->

 
 
 
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注册bean之后就对象的初始化了（类似 new 类名()）

弹幕评论：

name方式还需要无参构造和set方法,index和type只需要有参构造

就算是new 两个对象，也是只有一个实例（单例模式：全局唯一）

User user = (User) context.getBean("user");
User user2 = (User) context.getBean("user");
system.out.println(user == user2)//结果为true

 
 
 
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总结：在配置文件加载的时候，容器(< bean>)中管理的对象就已经初始化了

5、Spring配置

5.1、别名

<bean id="user" class="pojo.User">
    <constructor-arg name="name" value="chen"></constructor-arg>
</bean>
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5.2、Bean的配置

<!--id：bean的唯一标识符，也就是相当于我们学的对象名
class：bean对象所对应的会限定名：包名+类型
name：也是别名，而且name可以同时取多个别名 -->
<bean id="user" class="pojo.User" name="u1 u2,u3;u4">
    <property name="name" value="chen"/>
</bean>
<!-- 使用时
	User user2 = (User) context.getBean("u1");	
-->

 
 
 
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5.3、import

import一般用于团队开发使用，它可以将多个配置文件，导入合并为一个

假设，现在项目中有多个人开发，这三个人复制不同的类开发，不同的类需要注册在不同的bean中，我们可以利
用import将所有人的beans.xml合并为一个总的！

张三(beans.xm1)
李四(beans2.xm1)
王五(beans3.xm1)

applicationContext.xml

<import resource="beans.xm1"/>
<import resource="beans2.xml"/>
<import resource="beans3.xm1"/>

   
   
   
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使用的时候，直接使用总的配置就可以了

弹幕评论：

按照在总的xml中的导入顺序来进行创建，后导入的会重写先导入的，最终实例化的对象会是后导入xml中的那个

6、依赖注入（DI）

6.1、构造器注入

第4点有提到

6.2、set方式注入【重点】

依赖注入：set注入！

依赖：bean对象的创建依赖于容器
注入：bean对象中的所有属性，由容器来注入

【环境搭建】

复杂类型

Address类
真实测试对象

Student类
beans.xml
测试

MyTest3

Student类

package pojo;
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import java.util.*;
@Get
@Set
public class Student {
//别忘了写get和set方法（用lombok注解也行）
private String name;
private Address address;

<span class="token keyword">private</span> String<span class="token punctuation">[</span><span class="token punctuation">]</span> books<span class="token punctuation">;</span>
<span class="token keyword">private</span> List<span class="token generics function"><span class="token punctuation">&lt;</span>String<span class="token punctuation">&gt;</span></span> hobbies<span class="token punctuation">;</span>

<span class="token keyword">private</span> Map<span class="token generics function"><span class="token punctuation">&lt;</span>String<span class="token punctuation">,</span> String<span class="token punctuation">&gt;</span></span> card<span class="token punctuation">;</span>
<span class="token keyword">private</span> Set<span class="token generics function"><span class="token punctuation">&lt;</span>String<span class="token punctuation">&gt;</span></span> game<span class="token punctuation">;</span>

<span class="token keyword">private</span> Properties infor<span class="token punctuation">;</span>
<span class="token keyword">private</span> String wife<span class="token punctuation">;</span>

<span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> String <span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> <span class="token string">"Student{"</span> <span class="token operator">+</span><span class="token string">"\n"</span><span class="token operator">+</span>
            <span class="token string">"name='"</span> <span class="token operator">+</span> name <span class="token operator">+</span> <span class="token string">'\''</span> <span class="token operator">+</span><span class="token string">"\n"</span><span class="token operator">+</span>
            <span class="token string">", address="</span> <span class="token operator">+</span> address<span class="token punctuation">.</span><span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">+</span><span class="token string">"\n"</span><span class="token operator">+</span>
            <span class="token string">", books="</span> <span class="token operator">+</span> Arrays<span class="token punctuation">.</span><span class="token function">toString</span><span class="token punctuation">(</span>books<span class="token punctuation">)</span> <span class="token operator">+</span><span class="token string">"\n"</span><span class="token operator">+</span>
            <span class="token string">", hobbies="</span> <span class="token operator">+</span> hobbies <span class="token operator">+</span><span class="token string">"\n"</span><span class="token operator">+</span>
            <span class="token string">", card="</span> <span class="token operator">+</span> card <span class="token operator">+</span><span class="token string">"\n"</span><span class="token operator">+</span>
            <span class="token string">", game="</span> <span class="token operator">+</span> game <span class="token operator">+</span><span class="token string">"\n"</span><span class="token operator">+</span>
            <span class="token string">", infor="</span> <span class="token operator">+</span> infor <span class="token operator">+</span><span class="token string">"\n"</span><span class="token operator">+</span>
            <span class="token string">", wife='"</span> <span class="token operator">+</span> wife <span class="token operator">+</span> <span class="token string">'\''</span> <span class="token operator">+</span><span class="token string">"\n"</span><span class="token operator">+</span>
            <span class="token string">'}'</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
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}

Address类

package pojo;
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public class Address {

<span class="token keyword">private</span> String address<span class="token punctuation">;</span>

<span class="token keyword">public</span> String <span class="token function">getAddress</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> address<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setAddress</span><span class="token punctuation">(</span>String address<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>address <span class="token operator">=</span> address<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> String <span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> <span class="token string">"Address{"</span> <span class="token operator">+</span>
            <span class="token string">"address='"</span> <span class="token operator">+</span> address <span class="token operator">+</span> <span class="token string">'\''</span> <span class="token operator">+</span>
            <span class="token string">'}'</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
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}

beans.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd">
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>bean</span> <span class="token attr-name">id</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>address<span class="token punctuation">"</span></span> <span class="token attr-name">class</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>pojo.Address<span class="token punctuation">"</span></span><span class="token punctuation">&gt;</span></span>
	<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>address<span class="token punctuation">"</span></span> <span class="token attr-name">value</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>address你好<span class="token punctuation">"</span></span> <span class="token punctuation">/&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>bean</span><span class="token punctuation">&gt;</span></span>

<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>bean</span> <span class="token attr-name">id</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>student<span class="token punctuation">"</span></span> <span class="token attr-name">class</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>pojo.Student<span class="token punctuation">"</span></span><span class="token punctuation">&gt;</span></span>
	<span class="token comment">&lt;!--第一种，普通值注入 --&gt;</span>
	<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>name<span class="token punctuation">"</span></span> <span class="token attr-name">value</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>name你好<span class="token punctuation">"</span></span> <span class="token punctuation">/&gt;</span></span>
	<span class="token comment">&lt;!--第二种，ref注入 --&gt;</span>
	<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>address<span class="token punctuation">"</span></span> <span class="token attr-name">ref</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>address<span class="token punctuation">"</span></span> <span class="token punctuation">/&gt;</span></span>

	<span class="token comment">&lt;!--数组注入 --&gt;</span>
	<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>books<span class="token punctuation">"</span></span><span class="token punctuation">&gt;</span></span>
		<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>array</span><span class="token punctuation">&gt;</span></span>
			<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>value</span><span class="token punctuation">&gt;</span></span>三国<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>value</span><span class="token punctuation">&gt;</span></span>
			<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>value</span><span class="token punctuation">&gt;</span></span>西游<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>value</span><span class="token punctuation">&gt;</span></span>
			<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>value</span><span class="token punctuation">&gt;</span></span>水浒<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>value</span><span class="token punctuation">&gt;</span></span>
		<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>array</span><span class="token punctuation">&gt;</span></span>
	<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>property</span><span class="token punctuation">&gt;</span></span>

	<span class="token comment">&lt;!--list列表注入 --&gt;</span>
	<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>hobbies<span class="token punctuation">"</span></span><span class="token punctuation">&gt;</span></span>
		<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>list</span><span class="token punctuation">&gt;</span></span>
			<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>value</span><span class="token punctuation">&gt;</span></span>唱<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>value</span><span class="token punctuation">&gt;</span></span>
			<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>value</span><span class="token punctuation">&gt;</span></span>跳<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>value</span><span class="token punctuation">&gt;</span></span>
			<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>value</span><span class="token punctuation">&gt;</span></span>rap<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>value</span><span class="token punctuation">&gt;</span></span>
			<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>value</span><span class="token punctuation">&gt;</span></span>篮球<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>value</span><span class="token punctuation">&gt;</span></span>
		<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>list</span><span class="token punctuation">&gt;</span></span>
	<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>property</span><span class="token punctuation">&gt;</span></span>

	<span class="token comment">&lt;!--map键值对注入 --&gt;</span>
	<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>card<span class="token punctuation">"</span></span><span class="token punctuation">&gt;</span></span>
		<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>map</span><span class="token punctuation">&gt;</span></span>
			<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>entry</span> <span class="token attr-name">key</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>username<span class="token punctuation">"</span></span> <span class="token attr-name">value</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>root<span class="token punctuation">"</span></span> <span class="token punctuation">/&gt;</span></span>
			<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>entry</span> <span class="token attr-name">key</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>password<span class="token punctuation">"</span></span> <span class="token attr-name">value</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>root<span class="token punctuation">"</span></span> <span class="token punctuation">/&gt;</span></span>
		<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>map</span><span class="token punctuation">&gt;</span></span>
	<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>property</span><span class="token punctuation">&gt;</span></span>

	<span class="token comment">&lt;!--set(可去重)注入 --&gt;</span>
	<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>game<span class="token punctuation">"</span></span><span class="token punctuation">&gt;</span></span>
		<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>set</span><span class="token punctuation">&gt;</span></span>
			<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>value</span><span class="token punctuation">&gt;</span></span>wangzhe<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>value</span><span class="token punctuation">&gt;</span></span>
			<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>value</span><span class="token punctuation">&gt;</span></span>lol<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>value</span><span class="token punctuation">&gt;</span></span>
			<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>value</span><span class="token punctuation">&gt;</span></span>galname<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>value</span><span class="token punctuation">&gt;</span></span>
		<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>set</span><span class="token punctuation">&gt;</span></span>
	<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>property</span><span class="token punctuation">&gt;</span></span>

	<span class="token comment">&lt;!--空指针null注入 --&gt;</span>
	<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>wife<span class="token punctuation">"</span></span><span class="token punctuation">&gt;</span></span>
		<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>null</span><span class="token punctuation">&gt;</span></span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>null</span><span class="token punctuation">&gt;</span></span>
	<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>property</span><span class="token punctuation">&gt;</span></span>

	<span class="token comment">&lt;!--properties常量注入 --&gt;</span>
	<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>infor<span class="token punctuation">"</span></span><span class="token punctuation">&gt;</span></span>
		<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>props</span><span class="token punctuation">&gt;</span></span>
			<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>prop</span> <span class="token attr-name">key</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>id<span class="token punctuation">"</span></span><span class="token punctuation">&gt;</span></span>20200802<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>prop</span><span class="token punctuation">&gt;</span></span>
			<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>prop</span> <span class="token attr-name">key</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>name<span class="token punctuation">"</span></span><span class="token punctuation">&gt;</span></span>cbh<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>prop</span><span class="token punctuation">&gt;</span></span>
		<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>props</span><span class="token punctuation">&gt;</span></span>
	<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>property</span><span class="token punctuation">&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>bean</span><span class="token punctuation">&gt;</span></span>
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</beans>

MyTest3

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import pojo.Student;
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public class MyTest3 {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext(“beans.xml”);
Student stu = (Student) context.getBean(“student”);
System.out.println(stu.toString());
}
}

6.3、拓展注入

官方文档位置

pojo增加User类

package pojo;
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public class User {
private String name;
private int id;
public User() {

<span class="token punctuation">}</span>
<span class="token keyword">public</span> <span class="token function">User</span><span class="token punctuation">(</span>String name<span class="token punctuation">,</span> <span class="token keyword">int</span> id<span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token keyword">super</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
	<span class="token keyword">this</span><span class="token punctuation">.</span>name <span class="token operator">=</span> name<span class="token punctuation">;</span>
	<span class="token keyword">this</span><span class="token punctuation">.</span>id <span class="token operator">=</span> id<span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token keyword">public</span> String <span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token keyword">return</span> name<span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setName</span><span class="token punctuation">(</span>String name<span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token keyword">this</span><span class="token punctuation">.</span>name <span class="token operator">=</span> name<span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">getId</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token keyword">return</span> id<span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setId</span><span class="token punctuation">(</span><span class="token keyword">int</span> id<span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token keyword">this</span><span class="token punctuation">.</span>id <span class="token operator">=</span> id<span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> String <span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token keyword">return</span> <span class="token string">"User [name="</span> <span class="token operator">+</span> name <span class="token operator">+</span> <span class="token string">", id="</span> <span class="token operator">+</span> id <span class="token operator">+</span> <span class="token string">"]"</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
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}

注意： beans 里面加上这下面两行

使用p和c命名空间需要导入xml约束

xmlns:p=“http://www.springframework.org/schema/p”
xmlns:c=“http://www.springframework.org/schema/c”

?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:c="http://www.springframework.org/schema/c"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd">
<span class="token comment">&lt;!--p命名空间注入/set注入，可以直接注入属性的值-》property--&gt;</span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>bean</span> <span class="token attr-name">id</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>user<span class="token punctuation">"</span></span> <span class="token attr-name">class</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>pojo.User<span class="token punctuation">"</span></span> <span class="token attr-name"><span class="token namespace">p:</span>name</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>cxk<span class="token punctuation">"</span></span> <span class="token attr-name"><span class="token namespace">p:</span>id</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>20<span class="token punctuation">"</span></span> <span class="token punctuation">&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>bean</span><span class="token punctuation">&gt;</span></span>

<span class="token comment">&lt;!--c命名空间，通过构造器注入，需要写入有参和无参构造方法-》construct-args--&gt;</span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>bean</span> <span class="token attr-name">id</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>user2<span class="token punctuation">"</span></span> <span class="token attr-name">class</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>pojo.User<span class="token punctuation">"</span></span> <span class="token attr-name"><span class="token namespace">c:</span>name</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>cbh<span class="token punctuation">"</span></span> <span class="token attr-name"><span class="token namespace">c:</span>id</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>22<span class="token punctuation">"</span></span><span class="token punctuation">&gt;</span></span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>bean</span><span class="token punctuation">&gt;</span></span>
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</beans>

测试

ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
User user = context.getBean("user",User.class);//确定class对象，就不用再强转了
System.out.println(user.toString());

 
 
 
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6.4、Bean作用域

单例模式（默认）

<bean id="user2" class="pojo.User" c:name="cxk" c:age="19" scope="singleton"></bean>

   
   
   
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弹幕评论：单例模式是把对象放在pool中，需要再取出来，使用的都是同一个对象实例

原型模式: 每次从容器中get的时候，都产生一个新对象！

<bean id="user2" class="pojo.User" c:name="cxk" c:age="19" scope="prototype"></bean>

   
   
   
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其余的request、session、application这些只能在web开放中使用！

7、Bean的自动装配

自动装配是Spring满足bean依赖的一种方式
Spring会在上下文自动寻找，并自动给bean装配属性

在Spring中有三种装配的方式

在xml中显示配置
在java中显示配置
隐式的自动装配bean 【重要】
环境搭建：一个人有两个宠物
byType自动装配：byType会自动查找，和自己对象set方法参数的类型相同的bean

保证所有的class唯一(类为全局唯一)

byName自动装配：byName会自动查找，和自己对象set对应的值对应的id

保证所有id唯一，并且和set注入的值一致

<!-- 找不到id和多个相同class -->
<bean id="cat1" class="pojo.Cat"/>
<bean id="cat2" class="pojo.Cat"/>
找不到 id=cat，且有两个Cat

   
   
   
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7.1测试：自动装配

pojo的Cat类

public class Cat {
    public void shut(){
        System.out.println("miao");
    }
}

 
 
 
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pojo的Dog类

public class Dog {
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">shut</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
    System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"wow"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
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}

pojo的People类

package pojo;
public class People {
<span class="token keyword">private</span> Cat cat<span class="token punctuation">;</span>
<span class="token keyword">private</span> Dog dog<span class="token punctuation">;</span>
<span class="token keyword">private</span> String name<span class="token punctuation">;</span>

<span class="token keyword">public</span> Cat <span class="token function">getCat</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> cat<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setCat</span><span class="token punctuation">(</span>Cat cat<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>cat <span class="token operator">=</span> cat<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> Dog <span class="token function">getDog</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> dog<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setDog</span><span class="token punctuation">(</span>Dog dog<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>dog <span class="token operator">=</span> dog<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> String <span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> name<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setName</span><span class="token punctuation">(</span>String name<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>name <span class="token operator">=</span> name<span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> String <span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> <span class="token string">"People{"</span> <span class="token operator">+</span>
            <span class="token string">"cat="</span> <span class="token operator">+</span> cat <span class="token operator">+</span>
            <span class="token string">", dog="</span> <span class="token operator">+</span> dog <span class="token operator">+</span>
            <span class="token string">", name='"</span> <span class="token operator">+</span> name <span class="token operator">+</span> <span class="token string">'\''</span> <span class="token operator">+</span>
            <span class="token string">'}'</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
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}

xml配置 -> byType 自动装配

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd">
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>bean</span> <span class="token attr-name">id</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>cat<span class="token punctuation">"</span></span> <span class="token attr-name">class</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>pojo.Cat<span class="token punctuation">"</span></span><span class="token punctuation">/&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>bean</span> <span class="token attr-name">id</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>dog<span class="token punctuation">"</span></span> <span class="token attr-name">class</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>pojo.Dog<span class="token punctuation">"</span></span><span class="token punctuation">/&gt;</span></span>

<span class="token comment">&lt;!--byType会在容器自动查找，和自己对象属性相同的bean
	例如，Dog dog; 那么就会查找pojo的Dog类，再进行自动装配
--&gt;</span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>bean</span> <span class="token attr-name">id</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>people<span class="token punctuation">"</span></span> <span class="token attr-name">class</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>pojo.People<span class="token punctuation">"</span></span> <span class="token attr-name">autowire</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>byType<span class="token punctuation">"</span></span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>name<span class="token punctuation">"</span></span> <span class="token attr-name">value</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>cbh<span class="token punctuation">"</span></span><span class="token punctuation">&gt;</span></span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>property</span><span class="token punctuation">&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>bean</span><span class="token punctuation">&gt;</span></span>
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</beans>

xml配置 -> byName 自动装配

<bean id="cat" class="pojo.Cat"/>
<bean id="dog" class="pojo.Dog"/>
<!--byname会在容器自动查找，和自己对象set方法的set后面的值对应的id
  例如:setDog()，取set后面的字符作为id，则要id = dog 才可以进行自动装配
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–>
<bean id=“people” class=“pojo.People” autowire=“byName”>
<property name=“name” value=“cbh”></property>
</bean>

弹幕评论：byName只能取到小写，大写取不到

7.2、使用注解实现自动装配

jdk1.5支持的注解，spring2.5支持的注解

The introduction of annotation-based configuration raised the question of whether this approach is “better” than XML.（翻译：基于注释的配置的引入提出了一个问题，即这种方法是否比XML“更好”）

导入context约束

xmlns:context="http://www.springframework.org/schema/context"

配置注解的支持：< context:annotation-config/>

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd">
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span><span class="token namespace">context:</span>annotation-config</span><span class="token punctuation">/&gt;</span></span>
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</beans>

7.2.1、@Autowired

默认是byType方式，如果匹配不上，就会byName

在属性上个使用，也可以在set上使用

我们可以不用编写set方法了，前提是自动装配的属性在Spring容器里，且要符合ByName 自动装配

public class People {
    @Autowired
    private Cat cat;
    @Autowired
    private Dog dog;
    private String name;
}

 
 
 
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@Nullable 字段标记了这个注解，说明该字段可以为空

public name(@Nullable String name){

}

//源码
public @interface Autowired { 
	boolean required() default true; 
}

 
 
 
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如果定义了Autowire的require属性为false，说明这个对象可以为null，否则不允许为空（false表示找不到装配，不抛出异常）

7.2.2、@Autowired+@Qualifier

@Autowired不能唯一装配时，需要@Autowired+@Qualifier

如果@Autowired自动装配环境比较复杂。自动装配无法通过一个注解完成的时候，可以使用@Qualifier(value = “dog”)去配合使用，指定一个唯一的id对象

public class People {
    @Autowired
    private Cat cat;
    @Autowired
    @Qualifier(value = "dog")
    private Dog dog;
    private String name;
}

 
 
 
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弹幕评论：

如果xml文件中同一个对象被多个bean使用，Autowired无法按类型找到，可以用@Qualifier指定id查找

7.2.3、@Resource

默认是byName方式，如果匹配不上，就会byType

public class People {
    Resource(name="cat")
    private Cat cat;
    Resource(name="dog")
    private Dog dog;
    private String name;
}

 
 
 
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弹幕评论：

Autowired是byType，@Autowired+@Qualifier = byType || byName

Autowired是先byteType,如果唯一則注入，否则byName查找。resource是先byname,不符合再继续byType

区别：

@Resource和@Autowired的区别：

都是用来自动装配的，都可以放在属性字段上
@Autowired通过byType的方式实现，而且必须要求这个对象存在！【常用】
@Resource默认通过byname的方式实现，如果找不到名字，则通过byType实现！如果两个都找不到的情况下，就报错！【常用】
执行顺序不同：@Autowired通过byType的方式实现。@Resource默认通过byname的方式实现

8、使用注解开发

在spring4之后，使用注解开发，必须要保证aop包的导入

使用注解需要导入contex的约束

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd">
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span><span class="token namespace">context:</span>annotation-config</span><span class="token punctuation">/&gt;</span></span>
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</beans>

8.1、bean

弹幕评论：
有了< context:component-scan>，另一个< context:annotation-config/>标签可以移除掉，因为已经被包含进去了。

<!--指定要扫描的包，这个包下面的注解才会生效
	别只扫一个com.kuang.pojo包--> 
<context:component-scan base-package="com.kuang"/> 
<context:annotation-config/>

 
 
 
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//@Component 组件
//等价于<bean id="user" classs"pojo.User"/> 
@Component
public class User {  
     public String name ="秦疆";
}

 
 
 
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8.2、属性如何注入@value

@Component
public class User { 
    //相当于<property name="name" value="kuangshen"/> 
    @value("kuangshen") 
    public String name; 
<span class="token comment">//也可以放在set方法上面</span>
<span class="token comment">//@value("kuangshen")</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setName</span><span class="token punctuation">(</span>String name<span class="token punctuation">)</span> <span class="token punctuation">{</span> 
    <span class="token keyword">this</span><span class="token punctuation">.</span>name <span class="token operator">=</span> name<span class="token punctuation">;</span> 
<span class="token punctuation">}</span>
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}

8.3、衍生的注解

@Component有几个衍生注解，会按照web开发中，mvc架构中分层。

dao （@Repository）
service（@Service）
controller（@Controller）

这四个注解的功能是一样的，都是代表将某个类注册到容器中

8.4、自动装配置

@Autowired：默认是byType方式，如果匹配不上，就会byName

@Nullable：字段标记了这个注解，说明该字段可以为空

@Resource：默认是byName方式，如果匹配不上，就会byType

8.5、作用域@scope

//原型模式prototype，单例模式singleton
//scope("prototype")相当于<bean scope="prototype"></bean>
@Component 
@scope("prototype")
public class User { 
<span class="token comment">//相当于&lt;property name="name" value="kuangshen"/&gt; </span>
<span class="token annotation punctuation">@value</span><span class="token punctuation">(</span><span class="token string">"kuangshen"</span><span class="token punctuation">)</span> 
<span class="token keyword">public</span> String name<span class="token punctuation">;</span> 

<span class="token comment">//也可以放在set方法上面</span>
<span class="token annotation punctuation">@value</span><span class="token punctuation">(</span><span class="token string">"kuangshen"</span><span class="token punctuation">)</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setName</span><span class="token punctuation">(</span>String name<span class="token punctuation">)</span> <span class="token punctuation">{</span> 
    <span class="token keyword">this</span><span class="token punctuation">.</span>name <span class="token operator">=</span> name<span class="token punctuation">;</span> 
<span class="token punctuation">}</span>
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}

8.6、小结

xml与注解：

xml更加万能，维护简单，适用于任何场合
注解，不是自己的类使用不了，维护复杂

最佳实践：

xml用来管理bean
注解只用来完成属性的注入
要开启注解支持

9、使用Java的方式配置Spring

不使用Spring的xml配置，完全交给java来做！

Spring的一个子项目，在spring4之后，，，它成为了核心功能

实体类：pojo的User.java

//这里这个注解的意思,就是说明这个类被Spring接管了,注册到了容器中 
@component 
public class User { 
    private String name;
<span class="token keyword">public</span> String <span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> 
	<span class="token keyword">return</span> name<span class="token punctuation">;</span> 
<span class="token punctuation">}</span> 
<span class="token comment">//属性注入值</span>
<span class="token annotation punctuation">@value</span><span class="token punctuation">(</span>"QINJIANG'<span class="token punctuation">)</span>  
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setName</span><span class="token punctuation">(</span>String name<span class="token punctuation">)</span> <span class="token punctuation">{</span> 
	<span class="token keyword">this</span><span class="token punctuation">.</span>name <span class="token operator">=</span> name<span class="token punctuation">;</span> 
<span class="token punctuation">}</span> 
<span class="token annotation punctuation">@Override</span> 
<span class="token keyword">public</span> String <span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> 
    <span class="token keyword">return</span> <span class="token string">"user{"</span> <span class="token operator">+</span> 
    <span class="token string">"name='"</span> <span class="token operator">+</span> name <span class="token operator">+</span> <span class="token string">'\''</span><span class="token operator">+</span> 
    <span class="token string">'}'</span><span class="token punctuation">;</span> 
<span class="token punctuation">}</span> 
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}

弹幕评论：要么使用@Bean，要么使用@Component和ComponentScan，两种效果一样

配置文件：config中的kuang.java

@Import(KuangConfig2.class)，用@import来包含KuangConfig2.java

//这个也会Spring容器托管,注册到容器中,因为他本米就是一个@Component 
// @Configuration表这是一个配置类,就像我们之前看的beans.xml，类似于<beans>标签
@Configuration 
@componentScan("com.Kuang.pojo") //开启扫描
//@Import(KuangConfig2.class)
public class KuangConfig { 
    //注册一个bean , 就相当于我们之前写的一个bean 标签 
    //这个方法的名字,就相当于bean 标签中的 id 属性 ->getUser
    //这个方法的返同值,就相当于bean 标签中的class 属性 ->User
<span class="token comment">//@Bean </span>
<span class="token keyword">public</span> User <span class="token function">getUser</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span> 
	<span class="token keyword">return</span> <span class="token keyword">new</span> <span class="token class-name">User</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//就是返回要注入到bean的对象! </span>
<span class="token punctuation">}</span> 
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}

弹幕评论：ComponentScan、@Component("pojo”) 这两个注解配合使用

测试类

public class MyTest { 
    public static void main(String[ ] args) { 
    //如果完全使用了配置类方式去做,我们就只能通过 Annotationconfig 上下文来获取容器,通过配置类的class对象加载! 
    ApplicationContext context = new AnnotationConfigApplicationContext(KuangConfig.Class); //class对象
    User getUser =(User)context.getBean( "getUser"); //方法名getUser
    System.out.Println(getUser.getName()); 
    } 
}

 
 
 
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会创建两个相同对象问题的说明：

弹幕总结 - -> @Bean是相当于< bean>标签创建的对象，而我们之前学的@Component是通过spring自动创建的这个被注解声明的对象，所以这里相当于有两个User对象被创建了。一个是bean标签创建的（@Bean），一个是通过扫描然后使用@Component，spring自动创建的User对象，所以这里去掉@Bean这些东西，然后开启扫描。之后在User头上用@Component即可达到spring自动创建User对象了

//这个也会Spring容器托管,注册到容器中,因为他本米就是一个@Component 
// @Configuration表这是一个配置类,就像我们之前看的beans.xml，类似于<beans>标签
@Configuration 
@componentScan("com.Kuang.pojo") //开启扫描
//@Import(KuangConfig2.class)
public class KuangConfig { 
    //注册一个bean , 就相当于我们之前写的一个bean 标签 
    //这个方法的名字,就相当于bean 标签中的 id 属性 ->getUser
    //这个方法的返同值,就相当于bean 标签中的class 属性 ->User
<span class="token comment">//@Bean </span>
<span class="token keyword">public</span> User <span class="token function">getUser</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span> 
	<span class="token keyword">return</span> <span class="token keyword">new</span> <span class="token class-name">User</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//就是返回要注入到bean的对象! </span>
<span class="token punctuation">}</span> 
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}

弹幕评论：ComponentScan、@Component("pojo”) 这两个注解配合使用

测试类

public class MyTest { 
    public static void main(String[ ] args) { 
    //如果完全使用了配置类方式去做,我们就只能通过 Annotationconfig 上下文来获取容器,通过配置类的class对象加载! 
    ApplicationContext context = new AnnotationConfigApplicationContext(KuangConfig.Class); //class对象
    User getUser =(User)context.getBean( "getUser"); //方法名getUser
    System.out.Println(getUser.getName()); 
    } 
}

 
 
 
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会创建两个相同对象问题的说明：

10、动态代理

代理模式是SpringAOP的底层

分类：动态代理和静态代理

10.1、静态代理

代码步骤：

1、接口

package pojo;
public interface Host {
	public void rent();
}

 
 
 
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2、真实角色

package pojo;
public class HostMaster implements Host{	
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">rent</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"房东要出租房子"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
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}

3、代理角色

package pojo;
public class Proxy {
<span class="token keyword">public</span> Host host<span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token function">Proxy</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token function">Proxy</span><span class="token punctuation">(</span>Host host<span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token keyword">super</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
	<span class="token keyword">this</span><span class="token punctuation">.</span>host <span class="token operator">=</span> host<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">rent</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token function">seeHouse</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
	host<span class="token punctuation">.</span><span class="token function">rent</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
	<span class="token function">fee</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
	<span class="token function">sign</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token comment">//看房</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">seeHouse</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"看房子"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token comment">//收费</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">fee</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"收中介费"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token comment">//合同</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">sign</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"签合同"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>		
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}

4、客户端访问代理角色

package holle4_proxy;
1

import pojo.Host;
import pojo.HostMaster;
import pojo.Proxy;

public class My {

<span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token comment">//房东要出租房子</span>
	Host host <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">HostMaster</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
	<span class="token comment">//中介帮房东出租房子，但也收取一定费用（增加一些房东不做的操作）</span>
	Proxy proxy <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Proxy</span><span class="token punctuation">(</span>host<span class="token punctuation">)</span><span class="token punctuation">;</span>
	<span class="token comment">//看不到房东，但通过代理，还是租到了房子</span>
	proxy<span class="token punctuation">.</span><span class="token function">rent</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
	
<span class="token punctuation">}</span>
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}

代码翻倍：几十个真实角色就得写几十个代理

AOP横向开发

10.2、动态代理

动态代理和静态角色一样，动态代理底层是反射机制

动态代理类是动态生成的，不是我们直接写好的！

动态代理(两大类)：基于接口，基于类

基于接口：JDK的动态代理【使用ing】
基于类：cglib
java字节码实现：javasisit

了解两个类
1、Proxy：代理
2、InvocationHandler：调用处理程序

实例：

接口 Host.java

//接口
package pojo2;
public interface Host {
	public void rent();
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}

接口Host实现类 HostMaster.java

//接口实现类
package pojo2;
public class HostMaster implements Host{	
	public void rent() {
		System.out.println("房东要租房子");
	}
}

 
 
 
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代理角色的处理程序类 ProxyInvocationHandler.java

package pojo2;
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import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

///用这个类，自动生成代理
public class ProxyInvocationHandler implements InvocationHandler {

<span class="token comment">// Foo f =(Foo) Proxy.NewProxyInstance(Foo. Class.GetClassLoader(),</span>
<span class="token comment">// new Class&lt;?&gt;[] { Foo.Class },</span>
<span class="token comment">// handler);</span>

<span class="token comment">// 被代理的接口</span>
<span class="token keyword">public</span> HostMaster hostMaster <span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setHostMaster</span><span class="token punctuation">(</span>HostMaster hostMaster<span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token keyword">this</span><span class="token punctuation">.</span>hostMaster <span class="token operator">=</span> hostMaster<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token comment">// 得到生成的代理类 </span>
<span class="token keyword">public</span> Object <span class="token function">getProxy</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token comment">// newProxyInstance() -&gt; 生成代理对象，就不用再写具体的代理类了</span>
	<span class="token comment">// this.getClass().getClassLoader() -&gt; 找到加载类的位置</span>
	<span class="token comment">// hostMaster.getClass().getInterfaces() -&gt; 代理的具体接口</span>
	<span class="token comment">// this -&gt; 代表了接口InvocationHandler的实现类ProxyInvocationHandler</span>
	<span class="token keyword">return</span> Proxy<span class="token punctuation">.</span><span class="token function">newProxyInstance</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">getClass</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getClassLoader</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> hostMaster<span class="token punctuation">.</span><span class="token function">getClass</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getInterfaces</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token keyword">this</span><span class="token punctuation">)</span><span class="token punctuation">;</span>


<span class="token comment">// 处理代理实例并返回结果</span>
<span class="token keyword">public</span> Object <span class="token function">invoke</span><span class="token punctuation">(</span>Object proxy<span class="token punctuation">,</span> Method method<span class="token punctuation">,</span> Object<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token keyword">throws</span> Throwable <span class="token punctuation">{</span>
	<span class="token function">seeHouse</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
	<span class="token comment">// 动态代理的本质，就是使用反射机制实现的</span>
    <span class="token comment">// invoke()执行它真正要执行的方法</span>
	Object result <span class="token operator">=</span> method<span class="token punctuation">.</span><span class="token function">invoke</span><span class="token punctuation">(</span>hostMaster<span class="token punctuation">,</span> args<span class="token punctuation">)</span><span class="token punctuation">;</span>
	<span class="token function">fee</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
	<span class="token keyword">return</span> result<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">seeHouse</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"看房子"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">fee</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"收中介费"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
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}

用户类 My2.java

package holle4_proxy;
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import pojo2.Host;
import pojo2.Host2;
import pojo2.HostMaster;
import pojo2.ProxyInvocationHandler;

public class My2 {

<span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    
	<span class="token comment">//真实角色</span>
	HostMaster hostMaster <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">HostMaster</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    
	<span class="token comment">//代理角色，现在没有；用代理角色的处理程序来实现Host接口的调用</span>
	ProxyInvocationHandler pih <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ProxyInvocationHandler</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    
    <span class="token comment">//pih -&gt; HostMaster接口类 -&gt; Host接口</span>
	pih<span class="token punctuation">.</span><span class="token function">setHostMaster</span><span class="token punctuation">(</span>hostMaster<span class="token punctuation">)</span><span class="token punctuation">;</span>
    
	<span class="token comment">//获取newProxyInstance动态生成代理类</span>
	Host proxy <span class="token operator">=</span> <span class="token punctuation">(</span>Host<span class="token punctuation">)</span> pih<span class="token punctuation">.</span><span class="token function">getProxy</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
	
	proxy<span class="token punctuation">.</span><span class="token function">rent</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token punctuation">}</span>
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}

弹幕评论：
什么时候调用invoke方法的?
代理实例调用方法时invoke方法就会被调用，可以debug试试

改为万能代理类

///用这个类，自动生代理
public class ProxyInvocationHandler implements InvocationHandler {
<span class="token comment">// 被代理的接口</span>
<span class="token keyword">public</span> Object target<span class="token punctuation">;</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setTarget</span><span class="token punctuation">(</span>Object target<span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token keyword">this</span><span class="token punctuation">.</span>target <span class="token operator">=</span> target<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token comment">// 得到生成的代理类 -&gt; 固定的代码</span>
<span class="token keyword">public</span> Object <span class="token function">getProxy</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token keyword">return</span> Proxy<span class="token punctuation">.</span><span class="token function">newProxyInstance</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">getClass</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getClassLoader</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> target<span class="token punctuation">.</span><span class="token function">getClass</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getInterfaces</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token keyword">this</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token comment">// 处理代理实例并返回结果</span>
<span class="token keyword">public</span> Object <span class="token function">invoke</span><span class="token punctuation">(</span>Object proxy<span class="token punctuation">,</span> Method method<span class="token punctuation">,</span> Object<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token keyword">throws</span> Throwable <span class="token punctuation">{</span>
	<span class="token comment">// 动态代理的本质，就是使用反射机制实现的</span>
	<span class="token comment">// invoke()执行它真正要执行的方法</span>
	Object result <span class="token operator">=</span> method<span class="token punctuation">.</span><span class="token function">invoke</span><span class="token punctuation">(</span>target<span class="token punctuation">,</span> args<span class="token punctuation">)</span><span class="token punctuation">;</span>
	<span class="token keyword">return</span> result<span class="token punctuation">;</span>
<span class="token punctuation">}</span>
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}

11、AOP

11.1、什么是AOP

11.2、AOP在Spring中的使用

提供声明式事务，允许用户自定义切面

横切关注点：跨越应用程序多个模块的方法或功能。即是，与我们业务逻辑无关的，但是我们需要关注的部分，就是横切关注点。如日志，安全，缓存，事务等等…
切面(Aspect)：横切关注点被模块化的特殊对象。即，它是一个类。（Log类）
通知(Advice)：切面必须要完成的工作。即，它是类中的一个方法。（Log类中的方法）
目标(Target)：被通知对象。（生成的代理类)
代理(Proxy)：向目标对象应用通知之后创建的对象。（生成的代理类）
切入点(PointCut)：切面通知执行的”地点”的定义。（最后两点：在哪个地方执行，比如：method.invoke()）
连接点(JointPoint)：与切入点匹配的执行点。

SpringAOP中，通过Advice定义横切逻辑，Spring中支持5种类型的Advice:

即AOP在不改变原有代码的情况下，去增加新的功能。（代理）

11.3、使用Spring实现AOP

导入jar包

<!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
<dependency>
    <groupId>org.aspectj</groupId>
    <artifactId>aspectjweaver</artifactId>
    <version>1.9.4</version>
</dependency>

 
 
 
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11.3.1、方法一：使用原生spring接口

springAPI接口实现

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
		https://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/aop
		https://www.springframework.org/schema/aop/spring-aop.xsd">
<span class="token comment">&lt;!--注册bean--&gt;</span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>bean</span> <span class="token attr-name">id</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>userservice<span class="token punctuation">"</span></span> <span class="token attr-name">class</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>service.UserServiceImpl<span class="token punctuation">"</span></span><span class="token punctuation">/&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>bean</span> <span class="token attr-name">id</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>log<span class="token punctuation">"</span></span> <span class="token attr-name">class</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>log.Log<span class="token punctuation">"</span></span><span class="token punctuation">/&gt;</span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>bean</span> <span class="token attr-name">id</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>afterLog<span class="token punctuation">"</span></span> <span class="token attr-name">class</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>log.AfterLog<span class="token punctuation">"</span></span><span class="token punctuation">/&gt;</span></span>
<span class="token comment">&lt;!--方式一，使用原生Spring API接口--&gt;</span>
<span class="token comment">&lt;!--配置aop,还需要导入aop约束--&gt;</span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span><span class="token namespace">aop:</span>config</span><span class="token punctuation">&gt;</span></span>
    <span class="token comment">&lt;!--切入点：expression:表达式，execution（要执行的位置）--&gt;</span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span><span class="token namespace">aop:</span>pointcut</span> <span class="token attr-name">id</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>pointcut<span class="token punctuation">"</span></span> <span class="token attr-name">expression</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>execution(* service.UserServiceImpl.*(..))<span class="token punctuation">"</span></span><span class="token punctuation">/&gt;</span></span>
    <span class="token comment">&lt;!--UserServiceImpl.*(..) -》 UserServiceImpl类下的所以方法(参数)--&gt;</span>
    <span class="token comment">&lt;!--执行环绕增加--&gt;</span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span><span class="token namespace">aop:</span>advisor</span> <span class="token attr-name">advice-ref</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>log<span class="token punctuation">"</span></span> <span class="token attr-name">pointcut-ref</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>pointcut<span class="token punctuation">"</span></span><span class="token punctuation">/&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span><span class="token namespace">aop:</span>advisor</span> <span class="token attr-name">advice-ref</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>afterLog<span class="token punctuation">"</span></span> <span class="token attr-name">pointcut-ref</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>pointcut<span class="token punctuation">"</span></span><span class="token punctuation">/&gt;</span></span>
    <span class="token comment">&lt;!-- 环绕,在id="pointcut"的前后切入 --&gt;</span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span><span class="token namespace">aop:</span>config</span><span class="token punctuation">&gt;</span></span>
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</beans>

execution(返回类型，类名，方法名(参数)) -> execution(* com.service.*,*(…))

UserService.java

package service;
public interface UserService {   
	    public void add() ;
	    public void delete() ;
	    public void query() ;
	    public void update();
}

 
 
 
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UserService 的实现类 UserServiceImp.java

package service;
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public class UserServiceImpl implements UserService {

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">add</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"add增"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">delete</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"delete删"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">update</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"update改"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">query</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"query查"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
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}

前置Log.java

package log;
import org.springframework.aop.MethodBeforeAdvice;
import java.lang.reflect.Method;
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public class Log implements MethodBeforeAdvice {
//method：要执行的目标对象的方法
//args：参数
//target：目标对象
public void before(Method method, Object[] args, Object target) throws Throwable {
System.out.println(target.getClass().getName()+“的”+method.getName()+“被执行了”);
}
}

后置AfterLog.java

package log;
import java.lang.reflect.Method;
import org.springframework.aop.AfterReturningAdvice;
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public class AfterLog implements AfterReturningAdvice {
//returnVaule: 返回值
public void afterReturning(Object returnValue, Method method, Object[] args, Object target) throws Throwable {
System.out.println(“执行了”+method.getName()+“方法，返回值是”+returnValue);
}
}

测试类MyTest5

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import service.UserService;
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public class MyTest5 {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext(“applicationContext.xml”);
//注意:动态代理代理的是接口
UserService userService = (UserService) context.getBean(“userservice”);
userService.add();
}
}

11.3.2、方法二：自定义类实现AOP

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xmlns:aop="http://www.springframework.org/schema/aop"
      xsi:schemaLocation="http://www.springframework.org/schema/beans
   	https://www.springframework.org/schema/beans/spring-beans.xsd
   	http://www.springframework.org/schema/aop
   	https://www.springframework.org/schema/aop/spring-aop.xsd">
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<!–注册bean–>
<bean id=“userservice” class=“service.UserServiceImpl”/>
<bean id=“log” class=“log.Log”/>
<bean id=“afterLog” class=“log.AfterLog”/>

<bean id=“diy” class=“diy.DiyPointcut”/>
<aop:config>
<!–自定义切面–>
<aop:aspect ref=“diy”>
<!–切入点–>
<aop:pointcut id=“point” expression=“execution(* service.UserServiceImpl.*(…))”/>
<aop:before method=“before” pointcut-ref=“point”/>
<aop:after method=“after” pointcut-ref=“point”/>
</aop:aspect>
</aop:config>

</beans>

package diy;
public class DiyPointcut {
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">before</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
    System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"插入到前面"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">after</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
    System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"插入到后面"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
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}

//测试
public class MyTest5 {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        //注意:动态代理代理的是接口
        UserService userService = (UserService) context.getBean("userservice");
        userService.add();
    }
}

 
 
 
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11.3.3、方法三：使用注解实现

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
		https://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/aop
		https://www.springframework.org/schema/aop/spring-aop.xsd">
<span class="token comment">&lt;!-- 注册 --&gt;</span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>bean</span> <span class="token attr-name">id</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>userservice<span class="token punctuation">"</span></span> <span class="token attr-name">class</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>service.UserServiceImpl<span class="token punctuation">"</span></span><span class="token punctuation">/&gt;</span></span>
<span class="token comment">&lt;!--方式三，使用注解实现--&gt;</span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>bean</span> <span class="token attr-name">id</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>diyAnnotation<span class="token punctuation">"</span></span> <span class="token attr-name">class</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>diy.DiyAnnotation<span class="token punctuation">"</span></span><span class="token punctuation">&gt;</span></span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>bean</span><span class="token punctuation">&gt;</span></span>

<span class="token comment">&lt;!-- 开启自动代理 
	实现方式：默认JDK (proxy-targer-class="fasle")
			 cgbin (proxy-targer-class="true")--&gt;</span>
<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span><span class="token namespace">aop:</span>aspectj-autoproxy</span><span class="token punctuation">/&gt;</span></span>
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</beans>

DiyAnnotation.java

package diy;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
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@Aspect //标注这个类是一个切面
public class DiyAnnotation {

<span class="token annotation punctuation">@Before</span><span class="token punctuation">(</span><span class="token string">"execution(* service.UserServiceImpl.*(..))"</span><span class="token punctuation">)</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">before</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
    System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"=====方法执行前====="</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token annotation punctuation">@After</span><span class="token punctuation">(</span><span class="token string">"execution(* service.UserServiceImpl.*(..))"</span><span class="token punctuation">)</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">after</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
    System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"=====方法执行后====="</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token comment">//在环绕增强中，我们可以给地暖管一个参数，代表我们要获取切入的点</span>
<span class="token annotation punctuation">@Around</span><span class="token punctuation">(</span><span class="token string">"execution(* service.UserServiceImpl.*(..))"</span><span class="token punctuation">)</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">around</span><span class="token punctuation">(</span>ProceedingJoinPoint joinPoint<span class="token punctuation">)</span> <span class="token keyword">throws</span> Throwable <span class="token punctuation">{</span>
    System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"环绕前"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

    Object proceed <span class="token operator">=</span> joinPoint<span class="token punctuation">.</span><span class="token function">proceed</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

    System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"环绕后"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
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}

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