SpringBoot中创建过滤器_springboot添加过滤器

一. 过滤器

过滤器依赖于servlet容器，可以过滤用户请求，但不能改变用户参数，因为ServletRequest只提供了getParameter方法没有setParameter方法，除非自己重新一个ServletRequest，自己实现一个setParameter方法，后续文章中再来尝试这个。今天主要给大家介绍SpringBoot中创建过滤器的两种方式

二. 通过bean注入的方式

1. 实现Filter接口，重写init，doFilter，destroy方法

package com.dhr.study.filter.beansss;

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

import javax.servlet.*;
import java.io.IOException;

@Slf4j
@Component
public class MyFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        log.info("非注解init");
    }


    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        log.info("非注解before");
        filterChain.doFilter(servletRequest, servletResponse);
        log.info("非注解after");
    }

    @Override
    public void destroy() {
        log.info("非注解destroy");
    }
}

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package com.dhr.study.filter.beansss;

import lombok.extern.slf4j.Slf4j;

import javax.servlet.*;
import java.io.IOException;

@Slf4j
public class MyFilter2 implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        log.info("非注解init2");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        log.info("非注解before2");
        filterChain.doFilter(servletRequest, servletResponse);
        log.info("非注解after2");
    }

    @Override
    public void destroy() {
        log.info("非注解destroy2");
    }
}

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2. 在配置类中注入这个bean

package com.dhr.study.filter.beansss;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.util.ArrayList;
import java.util.List;

@Configuration
public class MyFilterConfig {

    @Autowired
    private MyFilter myFilter;

    @Bean
    public FilterRegistrationBean oneFilter(){
//        MyFilterTwo myFilterTwo = new MyFilterTwo();
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
        //过滤器名称
        filterRegistrationBean.setName("myFilter");
        //注入过滤器
        filterRegistrationBean.setFilter(myFilter);
        List<String> urls = new ArrayList<>();
        urls.add("/test");
        filterRegistrationBean.setUrlPatterns(urls);
        //过滤器顺序
        filterRegistrationBean.setOrder(3);
        return filterRegistrationBean;
    }

    @Bean
    public FilterRegistrationBean twoFilter(){
//        MyFilterTwo myFilterTwo = new MyFilterTwo();
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
        //过滤器名称
        filterRegistrationBean.setName("myFilter2");
        //注入过滤器
        filterRegistrationBean.setFilter(new MyFilter2());
        List<String> urls = new ArrayList<>();
        urls.add("/test");
        filterRegistrationBean.setUrlPatterns(urls);
        //过滤器顺序
        filterRegistrationBean.setOrder(4);
        return filterRegistrationBean;
    }
}

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3. 执行结果
   order小的先执行
   

三. 通过注解的方式

1. 实现Filter接口

package com.dhr.study.filter.annotation;

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang.StringUtils;
import org.springframework.core.annotation.Order;
import org.springframework.util.CollectionUtils;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.annotation.WebInitParam;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

@WebFilter(filterName = "AnnotationFilter1", urlPatterns = {"/*"}, initParams = {@WebInitParam(name = "noFilterUrl", value = "/test")})
@Order(1)
@Slf4j
public class AnnotationFilter1 implements Filter {

    private List<String> noFilterUrls;

    @Override
    public void init(FilterConfig filterConfig) {
        log.info("####  AnnotationFilter1 ==== init ####");
        // 从过滤器配置中获取initParams参数
        String noFilterUrl = filterConfig.getInitParameter("noFilterUrl");
        // 将排除的URL放入成员变量noFilterUrls中
        if (StringUtils.isNotBlank(noFilterUrl)) {
            noFilterUrls = new ArrayList<>(Arrays.asList(noFilterUrl.split(",")));
        }
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        log.info("####  AnnotationFilter1 ==== doFilter before ####");
        // 过滤器配置的  urlPatterns  为 /* 表示过滤所有的请求
        // 有请求进来时，会先进入到过滤器中，此时则获取请求的uri地址
        String url = ((HttpServletRequest) servletRequest).getRequestURI();
        Boolean flag = false;
        if (!CollectionUtils.isEmpty(noFilterUrls)) {
            for (String noFilterUrl : noFilterUrls) {
                // 如果请求的地址中包含有 initParams 传递的参数值，则不继续向下执行
                if (url.contains(noFilterUrl)) {
                    flag = true;
                    break;
                }
            }
        }
        if (!flag) {
            //过滤请求响应逻辑
            log.info("过滤请求响应逻辑");
        }else {
            filterChain.doFilter(servletRequest, servletResponse);
        }
        log.info("####  AnnotationFilter1 ==== doFilter after ####");
    }

    @Override
    public void destroy() {
        log.info("####  AnnotationFilter1 ==== destroy ####");
    }
}

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package com.dhr.study.filter.annotation;

import lombok.extern.slf4j.Slf4j;
import org.springframework.core.annotation.Order;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import java.io.IOException;

@WebFilter(filterName = "AnnotationFilter2",urlPatterns = {"/*"})
@Order(2)
@Slf4j
public class AnnotationFilter2 implements Filter {
    @Override
    public void init(FilterConfig filterConfig) {
        log.info("####  AnnotationFilter2 ==== init ####");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        log.info("####  AnnotationFilter2 ==== doFilter before ####");
        String msg = servletRequest.getParameter("msg");
        if("err".equalsIgnoreCase(msg)){
            throw new RuntimeException("传递参数有误，验证过滤器....");
        }
        filterChain.doFilter(servletRequest,servletResponse);
        log.info("####  AnnotationFilter2 ==== doFilter after ####");
    }

    @Override
    public void destroy() {
        log.info("####  AnnotationFilter2 ==== destroy ####");
    }
}

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2. 启动类上增加注解@ServletComponentScan

@ServletComponentScan
1

个人喜欢注解方式，你觉得呢