用数据库如果估计在线人数不是很多的话,用application 比较快!
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<html>
<head>
<%@ page import="java.sql.*"%><title>无标题文档</title>
</head><body>
<%
String englishName = request.getParameter("englishName");
String chineseName= request.getParameter("chineseName");
String address= request.getParameter("address");
String telephone = request.getParameter("telephone");
String Email= request.getParameter("Email");
Class.forName("oracle.jdbc.driver.OracleDriver");
String userName="javateach";
String password="javateach";
String dbUrl = "jdbc:oracle:thin:@172.16.35.30:1521:orcl";
Connection conn = DriverManager.getConnection(dbUrl,userName,password);
String sql="select count(*)as num from user_t_info where englishName='" + englishName+"'";
Statement st=conn.createStatement();
ResultSet rs= st.executeQuery(sql);
rs.next();
if(rs.getInt("num") > 0)
{
%>
<script>
alert("用户已经注册!");
history.go(-1);
</script>
<%
conn.close();
return;
}
String sqlStr="insert into user_t_info (englishName,chineseName,address,telephone,Email) values ('"+ englishName + "','"+ chineseName + "','"+ address + "','"+ telephone+ "','"+ Email +"')";
rs.next();
if(st.executeUpdate(sqlStr) == 1)
{
out.print("成功了");
}
else
{
out.print("failed");
}
%></body>
</html>
session.setAttribute(name,listener);//监听session是否过期import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import elms.sql.DBConnection;/*public class listener extends HttpServlet
{
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException,IOException
{
response.setContentType("text/plain");
HttpSession session = request.getSession();
session.setAttribute("stuloginname",new CustomBindingListener(getServletContext()));
session.setAttribute("stuloginname",""+Math.random());
session.setMaxInactiveInterval(5);
}
}*/public class listener implements HttpSessionBindingListener
{
private ServletContext context;
public listener(ServletContext context)
{
this.context = context;
}
public void valueBound(HttpSessionBindingEvent event)
{
}
//=========================用户权限session过期后取消用户登录状态=============================================
public void valueUnbound(HttpSessionBindingEvent event)
{
try
{
elms.sql.DBConnection conn = new elms.sql.DBConnection();
//System.out.println("ok1");
String stuloginvalue = (String)event.getName();
//System.out.println(stuloginvalue);
//System.out.println("ok2");
String update_sql = "update student_info set Onlinestatus='0' where studentno='"+stuloginvalue+"'";
conn.executeQuery(update_sql);
conn.close();
//System.out.println("ok3");
}
catch(Exception e)
{
//System.out.println(e.getMessage());
}
}
}
这样可以的,但是在用户意外断电的时候必须要等session过期后才可以用的