common.java

网络邮件系统

/*
 * This product includes software developed by the
 * Apache Software Foundation (http://www.apache.org/).
 */
package ch05.controller;

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

/**
 * 针对所有页面的共同Servlet
 * 执行例如功能页面的跳转、退出登录等功能
 * @author ShenYK
 * @version 1.0
 */
public class Common extends HttpServlet
{
    public void doGet ( HttpServletRequest request, 
                        HttpServletResponse response )
        throws ServletException, IOException 
    {
        //设置提交表单的中文编码
        request.setCharacterEncoding("GBK");
        
        HttpSession mySession = request.getSession(true);
        
        //清空错误消息
        mySession.setAttribute("errMsg","");
        
        //是否非法进入本页面
        if ( mySession.getAttribute("username") == null )
        {
            response.sendRedirect("/ch05/login.jsp");
            return;
        }
        //是否进入默认页面
        if ( !request.getParameterNames().hasMoreElements() )
        {
            response.sendRedirect("/ch05/login.jsp");
            return;
        }
        
        
    	//得到用户输入信息
        String sGotoPage = request.getParameter("gotoPage");
        String sLogout = request.getParameter("logout");
        
        //用户是否要退出登录
        if ( sLogout != null && sLogout.equals("yes") )
        {
            //清除session，并且退回到login画面
            mySession.invalidate();
            response.sendRedirect("/ch05/login.jsp");
            return;
        }
        
        //如果登录有效，则继续进行页面跳转
        if ( sGotoPage != null )
        {
            //收件箱
            if ( sGotoPage.equals("inbox") )
            {
                mySession.setAttribute("curPage", "inbox");
                response.sendRedirect("/ch05/servlet/Inbox");
                return;
            }
            //写邮件
            else if ( sGotoPage.equals("composite") )
            {
                mySession.setAttribute("curPage", "composite");
                response.sendRedirect("/ch05/servlet/Composite");
                return;
            }
            //发件箱
            else if ( sGotoPage.equals("sendbox") )
            {
                mySession.setAttribute("curPage", "sendbox");
                response.sendRedirect("/ch05/servlet/Sendbox");
                return;
            }
            //地址簿
            else if ( sGotoPage.equals("address") )
            {
                mySession.setAttribute("curPage", "address");
                response.sendRedirect("/ch05/servlet/Address");
                return;
            }
            //邮箱设置
            else if ( sGotoPage.equals("setting") )
            {
                mySession.setAttribute("curPage", "setting");
                response.sendRedirect("/ch05/servlet/Setting");
                return;
            }
            else
            {
                mySession.setAttribute("curPage", "login");
                response.sendRedirect("/ch05/login.jsp");
                return;
            }
        }
        else
        {
            //清除session，并且退回到login画面
            mySession.invalidate();
            response.sendRedirect("/ch05/login.jsp");
            return;
        }
    }
    
    public void doPost ( HttpServletRequest request, 
                         HttpServletResponse response )
        throws ServletException, IOException 
    {
        doGet( request, response );
    }
}