LDAP到底该怎么验证呢

public boolean loginCheckByLDAP(String username,String password){
boolean flag = true;
String initialContextFactory = "com.sun.jndi.ldap.LdapCtxFactory";
String ad4ProviderURL = "ldap://localhost:389";
String securityAuthentication = "hz";
String domain = "ou=clazz,dc=ourschool,dc=org";
if(!username.startsWith(domain)){
username = domain+"\\"+username;
}
Hashtable<String,String> env = new Hashtable<String,String>();
env.put(Context.INITIAL_CONTEXT_FACTORY, initialContextFactory);
env.put(Context.PROVIDER_URL, ad4ProviderURL);
env.put(Context.SECURITY_AUTHENTICATION, securityAuthentication);
env.put(Context.SECURITY_PRINCIPAL, username);
env.put(Context.SECURITY_CREDENTIALS, password);
LdapContext ctx = null;
try {
ctx = new InitialLdapContext(env, null);
} catch (NamingException e) {
System.out.println("Authentication error, username is: " + username);
flag = false;
}finally{
if(ctx!=null){
try {
ctx.close();
} catch (NamingException e) {
e.printStackTrace();
}
}
}
return flag;

}

为什么验证不了啊.....Authentication error, username is: ou=clazz,dc=ourschool,dc=org\hz