监听器的使用,以及实现, 测试

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
    <display-name>MyFilter</display-name>
  
    <filter>
        <filter-name>Myfilter</filter-name>
        <filter-class>com.MyFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>Myfilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    <servlet>
          <servlet-name>Test</servlet-name>
          <servlet-class>com.Test</servlet-class>
    </servlet>
    <servlet-mapping>
          <servlet-name>Test</servlet-name>
          <url-pattern>/test</url-pattern>
    </servlet-mapping>
</web-app>

//这是我的自定义监听
import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

public class MyFilter implements Filter{

    @Override
    public void destroy() {
        
    }

    @Override
    public void doFilter(ServletRequest arg0, ServletResponse arg1,FilterChain arg2) throws IOException, ServletException {
        
        HttpServletRequest request =( HttpServletRequest)arg0;
        
        
        System.out.println("----->"+request.getRequestURI());
        
        if("/MyFilter/test".equals(request.getRequestURI())){
            arg2.doFilter(arg0, arg1);
        }
    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {
        
    }
}


import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;

public class Test extends HttpServlet{

    private static final long serialVersionUID = 1L;

    @Override
    public void service(ServletRequest arg0, ServletResponse arg1){
        System.out.println("我是MyFilter类的测试标识");
        
    }
}

主要是针对WEB开发的3大包装类的监听