login.jsp

网上聊天室.用JSP+SQL+SERVLET+ SERVER 2000数据库等构建而成

<%@ page contentType="text/html;charset=gb2312" language="java" %>
<%@ page import="java.sql.*,java.io.*"%>
<%@ include file="include.inc"%>
<%@ page import="java.util.Vector"%>
<%@ page import="java.util.Date"%>
<%@ page import="com.bwm.login.user"%>

<%
	String username=request.getParameter("username");
	String password=request.getParameter("password");
	String submit=request.getParameter("submit");
        boolean flag=true;

	Class.forName(CLASSFORNAME);
	Connection con=DriverManager.getConnection(SERVER,USER,PWD);

	Statement stmt=con.createStatement();

	if(submit.equals("登陆"))
	{
		String isCorrect="select * from user_info where username='"+username+"'and password='"+password+"'";
		ResultSet rs=stmt.executeQuery(isCorrect);
		if(!rs.next())
		{
			out.println("<script language='javascript'>alert('用户名或密码错误');parent.location.href='login.html';</script>");
		}
		else
		{
			Vector temp=(Vector)application.getAttribute("myuser");
			if(application.getAttribute("myuser")==null)
			{
				temp=new Vector();
			}
			for(int i=0;i<temp.size();i++)
			{
				user tempuser=(user)temp.elementAt(i);
				if(tempuser.username.equals(username))
				{
					out.println("<script language='javascript'>alert('该用户已经登陆');window.location.href='login.html';</script>");
                                        flag=false;
                                }

			}


			user mylist=new user();
			mylist.username=username;
			//boolean flag=true;
			//保存当前登陆的用户名
			session.setAttribute("username",username);
			application.setAttribute("ul",username);

			Vector myuser=(Vector)application.getAttribute("myuser");
			if(myuser==null)
			{
				myuser=new Vector();
			}

			if(flag)
			{
				myuser.addElement(mylist);
			}
			application.setAttribute("myuser",myuser);
			application.setAttribute("myuserni",rs.getString("nicheng"));

			out.println("<script language='javascript'>window.location.href='chat.jsp';</script>");

		}

	}

	else if(submit.equals("注册"))
	{
		response.sendRedirect("zhuce.html");
	}

%>