logoutservlet.java

oa办公系统

package cn.jx.ecjtu.oa.servlets.users;

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

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import cn.jx.ecjtu.oa.common.Constant;
import cn.jx.ecjtu.oa.ps.pojo.LoginUser;
import cn.jx.ecjtu.oa.services.OnlineList;
import cn.jx.ecjtu.oa.services.Result;
import cn.jx.ecjtu.oa.services.ServiceFactory;
import cn.jx.ecjtu.oa.services.SysUserService;
import cn.jx.ecjtu.oa.services.UserInSession;

public class LogoutServlet extends HttpServlet {

	/**
	 * Destruction of the servlet. <br>
	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	/**
	 * The doGet method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
          this.doPost(request, response);
          
	}

	/**
	 * The doPost method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to post.
	 * @TODO 进行退出操作
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		
		HttpSession session  = request.getSession();
		UserInSession userinsession=null;
		userinsession=(UserInSession) session.getAttribute(Constant.USER_IN_SESSION);
		int      id=-1;
		if(null!=userinsession)  //获得当前用户的ID
		{
			id=userinsession.getId();
		}else
		{
			request.setAttribute("message","您没有登陆或已经退出!");
			request.getRequestDispatcher("error.jsp").forward(request,response);
		}
		
		ServletContext application =getServletContext();                      //获得上下文
		if(null!=application.getAttribute(Constant.ONLINELIST_IN_APPLICATION))        //假如在application中已经有在线人员列表
		 {
			 OnlineList list=(OnlineList) application.getAttribute(Constant.ONLINELIST_IN_APPLICATION);
			 LoginUser user=null;
			 user=list.getUserById(id);		 
			 if(null!=user)                                                           //如果该用户已经登陆了，则返回一个已经登陆错误到error.jsp
			 {
				 service.modifyOnlineTime(user);                                      //更新这个用户数据库中的在线时间
				 list.removeOnlineUser(user);                                         //把这个用户从在线用户列表中移出
				 session.removeAttribute(Constant.USER_IN_SESSION);
				 application.setAttribute(Constant.ONLINELIST_IN_APPLICATION, list);  //更新到Application的ONLINE_LIST
				 response.sendRedirect("logoutok.jsp");//到logoutok.jsp
			 }
			 else                                                                     //该用户已经退出了，则返回一个已经退出错误到error.jsp
			 {
				request.setAttribute("message","您没有登陆或已经退出!");
				request.getRequestDispatcher("error.jsp").forward(request,response);
			 }				 
			 
		 }
	}

	/**
	 * Initialization of the servlet. <br>
	 *
	 * @throws ServletException if an error occure
	 */
	private SysUserService service;                                                  //使用到的SysUserService的对象
	
	public void init() throws ServletException {
		service=(SysUserService)ServiceFactory.getService(SysUserService.class);     
	}

}