通过java.namming包实现LDAP用户登录认证，怎么区分账号被冻结、停用、不存在等异常的业务情况呢？

• 参考的是：网上普遍流传的LDAP连接的代码

public boolean auth(String username, String password) {     //设置相关常量     String initialContextFactory ="com.sun.jndi.ldap.LdapCtxFactory";     String ad4ProviderURL ="ldap://ip:port";     String securityAuthentication ="simple";     String domain ="ad4";      if (!username.startsWith(domain)) {         username = domain+""+ username;     }      /*      * 组织参数集合      */     Hashtable<String,String> env = new Hashtable<String,String>();     //set the initializing information of the context     env.put(javax.naming.Context.INITIAL_CONTEXT_FACTORY, initialContextFactory);     //set the URL of ldap server     env.put(javax.naming.Context.PROVIDER_URL, ad4ProviderURL);     //set the authentication mode     env.put(javax.naming.Context.SECURITY_AUTHENTICATION, securityAuthentication);     //set user of AD     env.put(javax.naming.Context.SECURITY_PRINCIPAL, username);     //set password of user     env.put(javax.naming.Context.SECURITY_CREDENTIALS, password);      /*      * 进行LDAP连接      */     javax.naming.ldap.LdapContext ctx = null;     //initialize the ldap context     try {         ctx = new javax.naming.ldap.InitialLdapContext(env, null);     } catch (javax.naming.NamingException ex) {         System.out.println("Authentication error, username is:"+ username);         return false;     } finally {         if (ctx != null) {             try {                 ctx.close();             } catch (javax.naming.NamingException ex) {                 System.out.println("Close Authentication context error");                 ex.printStackTrace();             }             return true;    //获取的LdapContext对象不为空，则为登录成功         }     }     return false;    //否则登录失败 }