拦截JSP页面，校验是否已登录详解及实现代码

拦截jsp页面，校验是否已登录

   最近使用struts2做项目，需要拦截jsp以校验是否已经登，但struts2的过滤器链只能过滤action。后来发现在web.xml里可以直接增加javax.servlet.filter实现类的过滤器，可以过滤jsp。请看代码

filter实现类

<span style="font-size:18px;">package com.common; 
 
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.httpservlet; 
import javax.servlet.http.httpservletrequest; 
import javax.servlet.http.httpservletresponse; 
 
public class loginfilter extends httpservlet implements filter {  
    
  private static final long serialversionuid = 1l;  
  
  @override  
  public void dofilter(servletrequest request, servletresponse response,  
      filterchain chain) throws ioexception, servletexception {  
    httpservletrequest req = (httpservletrequest)request;  
    httpservletresponse res = (httpservletresponse)response;  
    string path = req.getcontextpath(); 
    string indexpath = req.getscheme()+"://"+req.getservername()+":"+req.getserverport()+path+ "/pages/login.jsp"; 
    if(req.getrequesturi().endswith("login.jsp")) 
    { 
      chain.dofilter(request, response);  
      return; 
    } 
     
    object loginuser = req.getsession().getattribute("<strong><span style="color:#ff0000;">loginsession</span></strong>");  
    if(loginuser == null){ 
      res.sendredirect(indexpath);  
      return;  
    } 
    chain.dofilter(request, response);  
  }  
  
  @override  
  public void init(filterconfig arg0) throws servletexception {  
    // todo auto-generated method stub   
  }  
  
}  
</span> 

登录方法：

<span style="font-size:18px;"> public string login() 
  { 
    login login = new login(); 
       
    //.......校验登录信息 
    actioncontext ctx = actioncontext.getcontext(); 
    map<string, object> session = ctx.getsession(); 
    session.put("<strong><span style="color:#ff0000;">loginsession</span></strong>", login); 
    return "success"; 
  }</span> 

 web.xml配置

<filter>  
   <filter-name>setlog</filter-name>  
   <filter-class>com.common.loginfilter</filter-class>  
</filter>  
<filter-mapping>  
   <filter-name>setlog</filter-name>  
   <url-pattern>/pages/home.jsp</url-pattern> 
   <url-pattern>/pages/channel/*</url-pattern> 
   <url-pattern>/pages/content/*</url-pattern> 
   <url-pattern>/pages/product/*</url-pattern> 
   <url-pattern>/pages/vodtask/*</url-pattern> 
</filter-mapping> 

注意，如果页面上使用了框架，则可能导致session超时后退出到登录页面，此时登录页面显示在框架的某个子页面，解决方法，在登录页面加入如下代码即可。

<span style="font-size: 18px;">  <script language="javascript">   
    if (top != window)   
      top.location.href = window.location.href;   
  </script></span> 

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