Java LDAP - Determine if user in a given group?

Question

We logon users to Active Directory via LDAP using the Java LDAP API. We want to enhance our logon functionality to further check if the user is in a given AD group. Does a

Answer 1

The easiest way is with 'lookup': (to open an Ldap Context: look above examples)

 /**
  * Tests if an Active Directory user exists in an Active Directory group. 
  * @param ctx LDAP Context.
  * @param dnADGroup distinguishedName of group.
  * @param dnADUser distinguishedName of user.
  * @return True if user is member of group.
  */


public static boolean isMemberOfADGroup(LdapContext ctx, String dnADGroup, String dnADUser) {
  try {
   DirContext lookedContext = (DirContext) (ctx.lookup(dnADGroup));
   Attribute attrs = lookedContext.getAttributes("").get("member");
   for (int i = 0; i < attrs.size(); i++) {
    String foundMember = (String) attrs.get(i);
    if(foundMember.equals(dnADUser)) {
     return true;
    }
   }
  } catch (NamingException ex) {
   String msg = "There has been an error trying to determin a group membership for AD user with distinguishedName: "+dnADUser;
   System.out.println(msg);
   ex.printStackTrace();
  }
  return false;
 }