JSP通过LDAP验证用户问题

HTML code:
<%@page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>
<%@ page import="java.util.Hashtable"%>
<%@ page import="javax.naming.Context"%>
<%@ page import="javax.naming.NamingException"%>
<%@ page import="javax.naming.directory.DirContext"%>
<%@ page import="javax.naming.directory.InitialDirContext"%>


<%

String account="0119900014";
String password="biint";
String root="dc=biint,dc=com,dc=cn"; //root

Hashtable env = new Hashtable();
env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
env.put(Context.PROVIDER_URL, "ldap://211.83.108.124:389/" + root);
env.put(Context.SECURITY_AUTHENTICATION, "simple");
env.put(Context.SECURITY_PRINCIPAL, "uid=" + account + "," + root);
env.put(Context.SECURITY_CREDENTIALS, password);
DirContext ctx = null;
try
{
ctx = new InitialDirContext(env);
out.println("认证成功");
}
catch(javax.naming.AuthenticationException e)
{
out.println("认证失败:");