FirstFilter.java代码：
package com.imooc.filter;
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;
import javax.servlet.http.HttpServletResponse;
public class FirstFilter implements Filter {
public void destroy() {
System.out.println("destroy---FirstFilter");
}
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
System.out.println("start.......doFilter()---FirstFilter");
//chain.doFilter(request,response);
HttpServletRequest req=(HttpServletRequest) request;
HttpServletResponse response2=(HttpServletResponse) response;
//重定向
response2.sendRedirect(req.getContextPath()+"/main.jsp");
System.out.println("end.......doFilter()---FirstFilter");
}
public void init(FilterConfig filterConfig) throws ServletException {
System.out.println("init---FirstFilter");
}
}
web.xml配置代码：
<?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" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
<display-name>ImoocFilte</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
<filter>
<filter-name>FirstFilter</filter-name>
<filter-class>com.imooc.filter.FirstFilter</filter-class>
<init-param>
<param-name>name</param-name>
<param-value>zhangsan</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>FirstFilter</filter-name>
<url-pattern>/index.jsp</url-pattern>
<dispatcher>REQUEST</dispatcher>
</filter-mapping>
<filter-mapping>
<filter-name>FirstFilter</filter-name>
<url-pattern>/main.jsp</url-pattern>
</filter-mapping>
<!--
<filter>
<filter-name>SecondFilter</filter-name>
<filter-class>com.imooc.filter.SecondFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>SecondFilter</filter-name>
<url-pattern>/index.jsp</url-pattern>
</filter-mapping>
-->
</web-app>
index.jsp代码：
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
This is my JSP page. <br>
<%
System.out.println("处理过程完成！");
%>
</body>
</html>
main.jsp代码：
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'main.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
This is my Main page. <br>
</body>
</html>
你服务器启动后是直接访问main.jsp页面吗？