filter过滤器

最新推荐文章于 2023-03-27 13:26:04 发布

wenwenhappy

最新推荐文章于 2023-03-27 13:26:04 发布

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<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
	xmlns="http://java.sun.com/xml/ns/javaee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
	http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
  <!--谁过滤-->

  <filter>
  <filter-name>Myfilter</filter-name>
  <filter-class>com.servlet.MyFilter</filter-class>
  </filter>

  <!--过滤谁-->
  <filter-mapping>
  <filter-name>Myfilter</filter-name>
  <url-pattern>/hello/*</url-pattern>
  </filter-mapping>
</web-app>
//java代码

package com.servlet;

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 MyFilter implements Filter{
	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		    HttpServletResponse resp=(HttpServletResponse)response;
		    HttpServletRequest req=(HttpServletRequest)request;
            if(true)
            	resp.sendRedirect(req.getContextPath()+"/login.jsp");
            else
		    chain.doFilter(request, response);
	}

	public void destroy() {
   System.out.println("filter destory,,,,");		
	}

	public void init(FilterConfig filterConfig) throws ServletException {
		System.out.println("filter init...");
		
	}


}