从LDAP获取组和用户

嗨，我正在尝试从LDAP和该组中的用户获取所有posixGroup。下面的代码是我到目前为止所做的事情，它返回了我所有的组，但是我不确定如何获得这些组的用户。请指导我这种方法好吗？还是我应该先获取用户，然后基于GID获取组名？

public static void main(String[] args) {
        Hashtable env = new Hashtable();
        env.put(Context.INITIAL_CONTEXT_FACTORY,"com.sun.jndi.ldap.LdapCtxFactory");
        env.put(Context.PROVIDER_URL,"ldap://192.168.*.*:389");
        env.put(Context.URL_PKG_PREFIXES, "com.sun.jndi.url"); 
        env.put(Context.REFERRAL, "ignore"); 
        env.put(Context.SECURITY_AUTHENTICATION, "simple"); 
        env.put(Context.SECURITY_PRINCIPAL, "cn=manager,dc=*,dc=*"); 
        env.put(Context.SECURITY_CREDENTIALS, "****");

        DirContext ctx;
        try {
            ctx = new InitialDirContext(env);
        } catch (NamingException e) {
            throw new RuntimeException(e);
        }

        NamingEnumeration results = null;
        try {

            SearchControls controls = new SearchControls();
            controls.setSearchScope(SearchControls.SUBTREE_SCOPE);

            results = ctx.search("ou=path,dc=*,dc=*", "(objectClass=posixGroup)",controls);
            // Go through each item in list
            while (results.hasMore()) {
                SearchResult nc = (SearchResult)results.next();
                Attributes att=     nc.getAttributes();                           
                System.out.println("Group Name "+ att.get("cn").get(0));
                System.out.println("GID "+ att.get("GidNumber").get(0));
            }
        } catch (NameNotFoundException e) {
            System.out.println("Error : "+e);
        } catch (NamingException e) {
            throw new RuntimeException(e);
        } finally {
            if (results != null) {
                try {
                    results.close();
                } catch (Exception e) {
                    System.out.println("Error : "+e);
                }
            }
            if (ctx != null) {
                try {
                    ctx.close();
                } catch (Exception e) {
                    System.out.println("Error : "+e);
                }
            }
        }      

    }