【JAVA EE】过滤器笔记

Filter是过滤器/拦截器。对全网字符集过滤器、URL级别的权限访问控制、过滤敏感词，实现对JSP、Servlet、Html、JS、CSS等文件进行拦截。

@WebFilter("/*")中/*表示拦截所有资源

package com.mashang.web;

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

@WebFilter("/*")
public class MyFilter implements Filter {
    //filter随着服务器的开启而创建，当filte一创建就调用该方法
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
//        Filter.super.init(filterConfig);

        System.out.println("MyFilter init");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        //
        servletRequest.setCharacterEncoding("utf8");
        servletResponse.setCharacterEncoding("utf8");
        System.out.println("doFilter");
        filterChain.doFilter(servletRequest,servletResponse);
        System.out.println("out");
    }

    @Override
    public void destroy() {
        System.out.println("MyFilter Destory");
    }

    
}