login.java

这是一个极其好的聊天系统(java+jsp+servlet)

package chatroom;
import java.sql.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
import java.io.*;

/**
 * Title:        JSP聊天室
 * Description:  Java语言演示程序：JSP聊天室，用于北京师范大学计算机系Java课程教学示范。
 * Copyright:    Copyright (c) 2002
 * Company:      北京师范大学计算中心
 * @author 张庆利
 * @version 1.0
 */

public class Login extends HttpServlet {
    public void doGet(HttpServletRequest request,HttpServletResponse response)
        throws IOException, ServletException{
     String name=request.getParameter("name");
     String password=request.getParameter("password");
     HttpSession session=request.getSession(true);
     
     PrintWriter out = response.getWriter();
     if(name==null||password==null)
     {
     	System.out.println("It is NULL!");
     	getServletConfig().getServletContext().getRequestDispatcher("/mytest/jsp/login.jsp").forward(request,response);
     }
     else
     System.out.println(name+"  "+password);
   //  int i;
   //  char[] Temp=password.toCharArray();
   //  for (i=0;i<password.length();i++) Temp[i]=(char)(Temp[i]+i+1);
   //  password=password.copyValueOf(Temp);
     DBconn DBconn1= new DBconn();
     String sql="select * from USERTABLE where USER_ID='"+name+"' and USER_PASSWORD='"+password+"'";
     ResultSet RS = DBconn1.executeQuery ("select * from USERTABLE ");//where USER_ID='"+name+"' and USER_PASSWORD='"+password+"'");
     System.out.println(sql);
     try{
     if (RS.next()){
         oneUser thisUser=new oneUser();
         String user_id = RS.getString("USER_ID");
         String user_password = RS.getString("USER_PASSWORD");
         String position=new String("0");
         java.util.Date dateTimenow=new java.util.Date();
         long longDateTimeNow=(long)dateTimenow.getTime();
         thisUser.setOneUser(user_id,user_password,longDateTimeNow,position);
         session.putValue("thisUser",thisUser);
         ServletContext application=getServletContext();
         userList theUserList;
         
         if (application.getAttribute("userlist")==null)
         {
         	System.out.println(" if (application.getAttribute(==null)");
         	 theUserList=new userList();
         }
         else 
         {
         	System.out.println("else");
         	theUserList=(userList)application.getAttribute("userlist");
         }
         theUserList.addUserList(user_id,user_password,longDateTimeNow,position);
         System.out.println(" user_id,user_password,l");
         application.setAttribute("userlist",theUserList);
         System.out.println(" uson.setAttributst;"); 
        // getServletConfig().getServletContext().getRequestDispatcher("/mytest/jsp/index.jsp").forward(request,response);
        getServletContext().getRequestDispatcher("/jsp/index.jsp").forward(request,response);
         System.out.println(" usetServletConfig()t;");
        }
     else
     {
     	System.out.println("YOU OUT");
        getServletConfig().getServletContext().getRequestDispatcher("/mytest/jsp/login.jsp").forward(request,response);
     }
       RS.close();
	}
     catch(SQLException ex){
        System.err.println("操作数据库错误："+ex.getMessage());
     }
  }
  public void doPost(HttpServletRequest request,HttpServletResponse response)
        throws IOException, ServletException {
        doGet(request, response);
  }
}