使用过滤器处理Session失效的问题

以下是Servlet过滤器的部分代码

      SessionControlFilter.java

 package com.xqx.multiuploadservlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;

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;
import javax.servlet.http.HttpSession;

import com.cyzt.model.Tuser;
import com.cyzt.util.Pubutil;

public class SessionControlFilter implements Filter {
 protected FilterConfig filterConfig;

 private String orgAndPersonloginpage;

 private String projectloginpage;
 
 Pubutil pub=new Pubutil();
 
   
 public void destroy() {
  // TODO Auto-generated method stub
  this.filterConfig = null;

 }

 public void doFilter(ServletRequest request, ServletResponse response,
   FilterChain chain) throws IOException, ServletException {
  // TODO Auto-generated method stub
  HttpServletRequest rq = (HttpServletRequest) request;
  String path = pub.getBasePath(rq);
  HttpServletResponse rp = (HttpServletResponse) response;
  HttpSession session = rq.getSession(true);
  Tuser user = (Tuser) session.getAttribute("User");
  Tuser ouser = (Tuser) session.getAttribute("OUser");
  Tuser puser = (Tuser) session.getAttribute("PUser");
  Tuser duser = (Tuser) session.getAttribute("DUser");
  
   rp.setCharacterEncoding("GBK");
  
  String request_url = rq.getRequestURI();// 得到用户的请求路径

  String contentpath_url = rq.getContextPath();// 得到web的上下文路径;
  String url = request_url.substring(contentpath_url.length());
  try {
   if (!request_url.equals("/kmcyzt/")&&request_url.indexOf("login.jsp") == -1
     && request_url.indexOf("projectlogin.jsp") == -1
     && request_url.indexOf("organizationlogin.do") == -1
     && request_url.indexOf("personlogin.do")==-1
     && request_url.indexOf("departmentlogin.do")==-1
     && user == null && ouser == null && puser == null
     && duser == null) {
    PrintWriter out = rp.getWriter();
    out.println("<script language='javascript' type='text/javascript'>");
    out.println("alert('由于你长时间没有操作,导致Session失效!请你重新登录!');window.top.location.href='"+path+"/projectlogin.jsp'");
   out.println("</script>");

   } else {
    chain.doFilter(request, response);

   }

  } catch (IOException e) {
   e.getMessage();
   e.printStackTrace();
  }

 }

 public void init(FilterConfig config) throws ServletException {
  // TODO Auto-generated method stub
  this.filterConfig = config;
  orgAndPersonloginpage = config
    .getInitParameter("OrgAndPersonLoginPage");
  projectloginpage = config.getInitParameter("ProjectLoginPage");
  if (orgAndPersonloginpage == null || projectloginpage == null) {
   throw new ServletException("InitialLoginPage faild!");
  }

 }

}

 

 

web.xml的配置文件如下:

 

<filter>
<filter-name>SessionControlFilter</filter-name>
<filter-class>com.xqx.multiuploadservlet.SessionControlFilter</filter-class>
<init-param>
    <param-name>OrgAndPersonLoginPage</param-name>
    <param-value>login.jsp</param-value>
</init-param>
<init-param>
    <param-name>ProjectLoginPage</param-name>
    <param-value>projectlogin.jsp</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>SessionControlFilter</filter-name>
<url-pattern>*.jsp</url-pattern>
</filter-mapping>

<filter-mapping>
<filter-name>SessionControlFilter</filter-name>
<url-pattern>*.do</url-pattern>
</filter-mapping>
<session-config>
<session-timeout>1</session-timeout>
</session-config>

 

 

另附如下的知识供理解:

 

假定你的web application 名称为news,你在浏览器中输入请求路径：

http://localhost:8080/news/main/list.jsp

 

则执行下面向行代码后打印出如下结果：

1、 System.out.println(request.getContextPath());

打印结果：/news
  2、System.out.println(request.getServletPath());

打印结果：/main/list.jsp
 3、 System.out.println(request.getRequestURI());

打印结果：/news/main/list.jsp
 4、 System.out.println(request.getRealPath("/"));

打印结果：F:/Tomcat 6.0/webapps/news/test