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切面编程+反射实现注解式开发_切面类中的invoke方法怎么写

作者：Gausst松鼠会 | 2024-03-12 19:08:08

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切面类中的invoke方法怎么写

1.本文实现的是订单查询中属性字段（用户名称为空.）通过注解反射方法给customerName填充值。

  1. package com.example.hello.annotation;
  2.  
  3. import java.lang.annotation.ElementType;
  4. import java.lang.annotation.Retention;
  5. import java.lang.annotation.RetentionPolicy;
  6. import java.lang.annotation.Target;
  7.  
  8. @Target({ElementType.FIELD,ElementType.METHOD})
  9. @Retention(RetentionPolicy.RUNTIME)
  10. /**
  11.  * 注解类
  12.  */
  13. public @interface NeedSetValueField {
  14.     Class<?> beanClass();
  15.     String param();
  16.     String method();
  17.     String targetField();
  18. }
  1. package com.example.hello.aspect;
  2.  
  3. import com.example.hello.util.BeanUtil;
  4. import org.aspectj.lang.ProceedingJoinPoint;
  5. import org.aspectj.lang.annotation.Around;
  6. import org.aspectj.lang.annotation.Aspect;
  7. import org.springframework.beans.factory.annotation.Autowired;
  8. import org.springframework.stereotype.Component;
  9.  
  10. import java.util.Collection;
  11.  
  12. @Component
  13. @Aspect
  14. public class SetFieldValueAspect {
  15.     @Autowired
  16.     BeanUtil beanUtil;
  17.  
  18.     /**
  19.      * 切面编程环绕执行
  20.      * @param joinPoint
  21.      * @return
  22.      * @throws Throwable
  23.      */
  24.     @Around("@annotation(com.example.hello.annotation.NeedSetValue)")
  25.     public Object doSetValue(ProceedingJoinPoint joinPoint)throws Throwable{
  26.        Object result = joinPoint.proceed();
  27.        // 操作结果集，得值进行设置
  28.         beanUtil.setValueByCol((Collection) result);
  29.        return result;
  30.     }
  31. }
  1. package com.example.hello.controller;
  2.  
  3. import com.example.hello.service.OrderService;
  4. import org.springframework.beans.factory.annotation.Autowired;
  5. import org.springframework.web.bind.annotation.RequestMapping;
  6. import org.springframework.web.bind.annotation.RestController;
  7.  
  8. @RestController
  9. public class OrderController {
  10.  
  11.     @Autowired
  12.     private OrderService orderService;
  13.  
  14.     /**
  15.      * 分页查询order
  16.      * @param customerId
  17.      * @param pageNum
  18.      * @param pageSize
  19.      * @return
  20.      * @throws Exception
  21.      */
  22.     @RequestMapping("query")
  23.     public Object query(String customerId, int pageNum, int pageSize)throws Exception{
  24.         return this.orderService.pageQuery(customerId,pageNum,pageSize);
  25.     }
  26. }
  1. package com.example.hello.controller;
  2.  
  3. import com.example.hello.service.OrderService;
  4. import org.springframework.beans.factory.annotation.Autowired;
  5. import org.springframework.web.bind.annotation.RequestMapping;
  6. import org.springframework.web.bind.annotation.RestController;
  7.  
  8. @RestController
  9. public class OrderController {
  10.  
  11.     @Autowired
  12.     private OrderService orderService;
  13.  
  14.     /**
  15.      * 分页查询order
  16.      * @param customerId
  17.      * @param pageNum
  18.      * @param pageSize
  19.      * @return
  20.      * @throws Exception
  21.      */
  22.     @RequestMapping("query")
  23.     public Object query(String customerId, int pageNum, int pageSize)throws Exception{
  24.         return this.orderService.pageQuery(customerId,pageNum,pageSize);
  25.     }
  26. }
  1. package com.example.hello.dao;
  2.  
  3. import com.example.hello.model.User;
  4. import com.sun.org.glassfish.gmbal.ParameterNames;
  5. import org.springframework.cache.annotation.Cacheable;
  6.  
  7. import java.util.List;
  8.  
  9. @Cacheable
  10. public class UserDao {
  11.  
  12.     void insert(User u) {
  13.  
  14.     }
  15.     void update(User u){}
  16.  
  17.     /**
  18.      * 查询用户列表
  19.      * @param username
  20.      * @return
  21.      */
  22.     List<User> query( String username){
  23.         return null;
  24.     }
  25.  
  26.     /**
  27.      * 根据id查询用户
  28.      * @param id
  29.      * @return
  30.      */
  31.     User find(String id){
  32.         User user = new User("1","1");
  33.         return user ;
  34.     }
  35. }
  1. package com.example.hello.model;
  2.  
  3.  
  4. import com.example.hello.annotation.NeedSetValueField;
  5. import com.example.hello.dao.UserDao;
  6.  
  7. import java.io.Serializable;
  8.  
  9. public class Order implements Serializable {
  10.     /**
  11.      * list={id:1,cid:1,cname:null}
  12.      */
  13.     private static final long serialVersion = 100000000L;
  14.  
  15.     private String id;
  16.  
  17.     private String customerId;
  18.     /**
  19.      * 通过注解实现给customerName赋值
  20.      */
  21.     @NeedSetValueField(beanClass = UserDao.class,param = "customerId",method = "find",targetField = "name")
  22.     private String customerName; //set值 后置方法---反射 user--find-->method.invoke()--->name---获取到具体值
  23.     // --->set
  24.  
  25.     public String getId() {
  26.         return id;
  27.     }
  28.  
  29.     public void setId(String id) {
  30.         this.id = id;
  31.     }
  32.  
  33.     public String getCustomerId() {
  34.         return customerId;
  35.     }
  36.  
  37.     public void setCustomerId(String customerId) {
  38.         this.customerId = customerId;
  39.     }
  40.  
  41.     public String getCustomerName() {
  42.         return customerName;
  43.     }
  44.  
  45.     public void setCustomerName(String customerName) {
  46.         this.customerName = customerName;
  47.     }
  48.  
  49.  
  50. }
  1. package com.example.hello.model;
  2.  
  3. public class User {
  4.     private static final long serialVersion = 100000001L;
  5.     public String getId() {
  6.         return id;
  7.     }
  8.  
  9.     public void setId(String id) {
  10.         this.id = id;
  11.     }
  12.  
  13.     private String id;
  14.  
  15.     public String getName() {
  16.         return name;
  17.     }
  18.  
  19.     public void setName(String name) {
  20.         this.name = name;
  21.     }
  22.  
  23.     private String name;
  24.     public User(String id,String name){
  25.         this.id = id;
  26.         this.name = name;
  27.     }
  28. }
  1. package com.example.hello.service;
  2.  
  3. import com.example.hello.annotation.NeedSetValue;
  4. import com.example.hello.dao.OrderDao;
  5. import com.example.hello.model.Order;
  6. import com.github.pagehelper.Page;
  7. import com.github.pagehelper.PageHelper;
  8. import org.springframework.beans.factory.annotation.Autowired;
  9. import org.springframework.stereotype.Service;
  10.  
  11. @Service
  12. public class OrderService {
  13.  
  14.     /**
  15.      * 1.获取和设置组件
  16.      * 2.首先，当调用组件时，我怎么知道设置哪些属性值
  17.      * 3，这个要告诉我
  18.      * 4.我怎么知道哪个bean的哪个方法，以及要传入的值
  19.      * 5.这个要告诉我
  20.      */
  22.     @Autowired
  23.     private OrderDao orderDao;
  24.     // 执行本方法进行切面
  25.     // 自定义注解切面
  26.     @NeedSetValue
  27.     public Page<Order> pageQuery(String customerId, int pageNum, int pageSize)throws Exception{
  28.         Page<Order> page = PageHelper.startPage(pageNum,pageSize);
  29.         this.orderDao.query(customerId);
  30.  
  31.         // 批量查询10条
  32.         // util --- setField(class bean,params,setField) ---可以解决问题
  33.         // 更加优雅的方法，不用改动原有的代码
  34.         // 使用AOP进行增强处理，对结果进行设置，再返回
  35.         // annotion 注解，能让类附上说明信息到运行期
  36.  
  37.  
  38.         return page;
  39.     }
  40. }
  1. package com.example.hello.util;
  2.  
  3. import com.example.hello.annotation.NeedSetValueField;
  4. import org.apache.commons.lang.StringUtils;
  5. import org.springframework.beans.BeansException;
  6. import org.springframework.context.ApplicationContext;
  7. import org.springframework.context.ApplicationContextAware;
  8. import org.springframework.stereotype.Component;
  9.  
  10. import java.lang.reflect.Field;
  11. import java.lang.reflect.Method;
  12. import java.util.Collection;
  13. import java.util.HashMap;
  14. import java.util.Map;
  15.  
  16. @Component
  17. public class BeanUtil implements ApplicationContextAware {
  18.     private ApplicationContext applicationContext;
  19.     @Override
  20.     public void setApplicationContext(ApplicationContext var1) throws BeansException{
  21.         this.applicationContext = applicationContext;
  22.     }
  23.  
  24.     public void setValueByCol(Collection col)throws Exception{
  25.         Class<?> clazz = col.iterator().next().getClass();
  26.         Field[] fields = clazz.getDeclaredFields();
  27.         Map<String,Object> cache = new HashMap<>();
  28.         for (Field field: fields) {
  29.             NeedSetValueField sv = field.getAnnotation(NeedSetValueField.class); //拿到定义在属性上的注解
  30.             if (sv == null)continue;
  31.             field.setAccessible(true);
  32.             Object bean = this.applicationContext.getBean(sv.beanClass()); // 得到bean（UserDao）
  33.             // bean中找到方法 ---find方法
  34.             Method method = sv.beanClass().getMethod(sv.method(),clazz.getDeclaredField(sv.param()).getType());
  35.             // customerId
  36.             Field paramField = clazz.getDeclaredField(sv.param());
  37.             paramField.setAccessible(true);
  38.  
  39.             Field targetField = null;
  40.             Boolean needInnerField = StringUtils.isNotEmpty(sv.targetField());
  41.             String keyPrefix = sv.beanClass()+"-"+sv.method()+"-"+sv.targetField()+"-";
  42.             for (Object obj:col) {
  43.                 Object paramValue = paramField.get(obj); // 3
  44.                 if (paramValue == null) continue;
  45.                 Object value = null;
  46.                 String key = keyPrefix;
  47.                 if (cache.containsKey(key)){
  48.                     value = cache.get(key);
  49.                 }else {
  50.                     value = method.invoke(bean,paramValue);  // User == value
  51.                     if (value != null){
  52.                         if (needInnerField){
  53.                             if (targetField == null){
  54.                                 targetField = value.getClass().getDeclaredField(sv.targetField());
  55.  
  56.                             }
  57.                             value = targetField.get(value);  // user中的名字tony
  58.                         }
  59.                     }
  60.  
  61.                     cache.put(key,value);
  62.                 }
  63.  
  64.                 field.set(obj,value); //field ---customerName
  65.             }
  66.  
  67.             // 参数具体的值
  68.             // method.invoke();
  69.         }
  70.     }
  71.  
  72.  
  73. }
  1. package com.example.hello;
  2.  
  3. import org.springframework.beans.factory.annotation.Value;
  4. import org.springframework.boot.SpringApplication;
  5. import org.springframework.boot.autoconfigure.SpringBootApplication;
  6. import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
  7. import org.springframework.web.bind.annotation.RequestMapping;
  8. import org.springframework.web.bind.annotation.RequestParam;
  9. import org.springframework.web.bind.annotation.RestController;
  10.  
  11. @SpringBootApplication
  12. @EnableEurekaClient
  13. @RestController
  14. public class ServiceHelloApplication {
  15.  
  16. 	public static void main(String[] args) {
  17. 		SpringApplication.run(ServiceHelloApplication.class, args);
  18. 	}
  19. 	@Value("${server.port}")
  20. 	String port;
  21.  
  22. 	@RequestMapping("/hello")
  23. 	public String home(@RequestParam(value = "name", defaultValue = "toher") String name) {
  24. 		return "hi " + name + " ,this is Feign Project , i am from port:" + port;
  25. 	}
  26.  
  27. }

项目结构：

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