javaWEB总结(30):配置Filter的dispatcher节点

栏目: JSP · 发布时间: 7年前

内容简介：javaWEB总结(30):配置Filter的dispatcher节点

目录结构

web.xml

<?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_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>javaWeb_30</display-name>
  <welcome-file-list>
    <welcome-file>login.jsp</welcome-file>
  </welcome-file-list>
  
  <filter>
      <filter-name>IndexFilter</filter-name>
      <filter-class>com.dao.chu.IndexFilter</filter-class>
  </filter>
  
  <filter-mapping>
      <filter-name>IndexFilter</filter-name>
      <url-pattern>/index.jsp</url-pattern>
  </filter-mapping>
  
</web-app>

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>login.jsp</title>
</head>
<body>
	<a href="<%=request.getContextPath() %>/index.jsp">To Index.jsp</a>
</body>
</html>

IndexFilter.java

package com.dao.chu;

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;

public class IndexFilter implements Filter {

	@Override
	public void destroy() {
	}

	@Override
	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		
		System.out.println("do Filter");
		
		chain.doFilter(request, response);
		
	}

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

}

index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>index.jsp</title>
</head>
<body>
	<h1>hello</h1>
</body>
</html>

运行结果

javaWEB总结(30):配置Filter的dispatcher节点

点击链接后

javaWEB总结(30):配置Filter的dispatcher节点

下面再login.jsp与index.jsp中加入dispatcher.jsp，并且通过转发的方式连到index.jsp页面。修改的页面如下:

javaWEB总结(30):配置Filter的dispatcher节点

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>login.jsp</title>
</head>
<body>
	<a href="<%=request.getContextPath() %>/dispatcher.jsp">To Index.jsp</a>
</body>
</html>

dispatcher.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>dispatcher.jsp</title>
</head>
<body>

	<jsp:forward page="/index.jsp"></jsp:forward>
</body>
</html>

其他页面不变

运行结果

javaWEB总结(30):配置Filter的dispatcher节点

可以看到控制台为空，并没有通过拦截器的doFilter方法，这是由于拦截器默认拦截的是请求的方式，而此处是转发的方式所以拦截不到，此时我们就要配置Filter的dispatcher节点。

我们修改web.xml文件，将dispachter节点配置为转发的方式:

<?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_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>javaWeb_30</display-name>
  <welcome-file-list>
    <welcome-file>login.jsp</welcome-file>
  </welcome-file-list>
  
  <filter>
      <filter-name>IndexFilter</filter-name>
      <filter-class>com.dao.chu.IndexFilter</filter-class>
  </filter>
  
  <filter-mapping>
      <filter-name>IndexFilter</filter-name>
      <url-pattern>/index.jsp</url-pattern>
      <dispatcher>FORWARD</dispatcher>
  </filter-mapping>
  
</web-app>

修改后重启tomcat,可看到如下运行效果

javaWEB总结(30):配置Filter的dispatcher节点