文章目录

一、Filter的使用

二、Filter的执行流程

三、过滤器链

案例：

package com.jkj.web.filter;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import java.io.IOException;
@WebFilter("/*")
public class FilterTest implements Filter {


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

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        //放行前
        System.out.println("1.FilterTest...");
        //放行
        filterChain.doFilter(servletRequest, servletResponse);
        System.out.println("5.FilterTest...");
    }

    @Override
    public void destroy() {

    }
}
/*
1.FilterTest...
2.Hello JSP!
3.FilterTest...
 */


package com.jkj.web.filter;

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

@WebFilter("/*")
public class FilterTest1 implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        //放行前
        System.out.println("2.FilterDemo...");
        //放行
        filterChain.doFilter(servletRequest, servletResponse);
        //放行后
        System.out.println("4.FilterDemo...");

    }

    @Override
    public void destroy() {

    }
}
/*
1.FilterTest...
2.FilterDemo...
3.Hello JSP!
4.FilterDemo...
5.FilterTest...
 */

  

 

  
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文章来源: blog.csdn.net，作者：不会压弯的小飞侠，版权归原作者所有，如需转载，请联系作者。

原文链接：blog.csdn.net/qq_43514330/article/details/125336493