拦截器与过滤器

流程图

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拦截器vs过滤器

拦截器是SpringMVC的技术

过滤器的Servlet的技术

先过过滤器，过滤器过完成才到DispatcherServlet；

拦截器归属于SpringMVC，只可能拦SpringMVC的东西；

拦截器说白了就是为了增强，可以在请求前进行增强，也可以在请求后进行增强，但是不一定同时在前后都增强。

区别

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SpringMVC技术架构图

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项目Demo

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Interceptor

package com.test.filtertest.inter;

import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author zhangzengxiu
 * @date 2022/4/22
 */
@Component
public class TestInter1 implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("TestInter1 preHandle...");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("TestInter1 postHandle...");
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("TestInter1 afterCompletion...");
    }
}

Interceptor拦截器要注册

package com.test.filtertest.config;

import com.test.filtertest.inter.TestInter1;
import com.test.filtertest.inter.TestInter2;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

/**
 * @author zhangzengxiu
 * @date 2022/4/22
 */
@Configuration
public class WebConfig implements WebMvcConfigurer {

    @Autowired
    private TestInter1 testInter1;

    @Autowired
    private TestInter2 testInter2;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //默认/** 拦截所有请求
        registry.addInterceptor(testInter1).addPathPatterns("/**");
        registry.addInterceptor(testInter2);
    }
}

Filter

package com.test.filtertest.filter;

import org.springframework.core.annotation.Order;

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

/**
 * @author zhangzengxiu
 * @date 2022/4/22
 */
@WebFilter(filterName = "TestFilter1", urlPatterns = "/*")
@Order(2)
public class TestFilter1 implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("TestFilter1 filter before ...");
        filterChain.doFilter(servletRequest, servletResponse);
        System.out.println("TestFilter1 filter after ...");
    }

    @Override
    public void destroy() {

    }
}