package com.kaka.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;

import org.apache.log4j.Logger;

public class LoginFilter implements Filter{
	
	private Logger logger = Logger.getLogger(LoginFilter.class);
	
	private static final String SHOW_LOGIN_PATH = "SHOW_LOGIN_PATH";    //显示登录页面  
    private static final String LOGIN_PERSONID = "LOGIN_PERSONID";      //登录用户在session中的属性key -- session.setAttribute(key,value)  
    private String showloginPath;  
    private String loginPersonId;  
      
    public void init(FilterConfig config) throws ServletException { 
    	logger.info("LoginFilter init...");
        showloginPath = config.getInitParameter(SHOW_LOGIN_PATH);  
        loginPersonId = config.getInitParameter(LOGIN_PERSONID);  
        if(showloginPath==null || showloginPath.equals("") || showloginPath.equals("null") ){  
            throw new ServletException("登录页面配置出错...");  
        }  
    }  
    
    /**
     * 对未登录的用户，请求跳转到登陆页面
     */
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {  
    	 
    	logger.info("LoginFilter doFilter...");
    	HttpServletRequest  httpReq  = (HttpServletRequest) request;  
        HttpServletResponse httpResp = (HttpServletResponse) response;  
        //判断是否是登陆页面  
        String servletPath = httpReq.getServletPath();  
        //flag:若为登陆页面的路径 /login.jsp,则赋值true，否则赋值false  
        if(servletPath.equals(showloginPath)){  
            chain.doFilter(request, response);  
            return;  
        }else{   //如果不是登录页面，则需先判断用户是否已登录  
            Object loginId = httpReq.getSession().getAttribute(loginPersonId);  
            if(loginId != null){//如果不为空,则进行已登录处理  
                chain.doFilter(request, response);  
            }else{//如果为空,则进行未登录处理  
                httpReq.getRequestDispatcher(showloginPath).forward(httpReq,httpResp);  
            }  
         }  
    }  
      
    public void destroy(){  
    	logger.info("LoginFilter destroy...");
    }  

}