Java如何使用DN从ldap获取属性？

Question

I have a Java application that I use to search groups. It works pretty well with search based on the group name (cn) but sometimes I get more than one result since the same cn is used in other branches. I have the DN of the group and I was wondering how to do a search based on the DN or if it's possible to access the attribute directly since I have the full path. Here is the code I use :

public Group getGroup( String groupName) throws Exception {

        List<User> memberList = new ArrayList<User>();

        // Create the search controls
        SearchControls searchCtls = new SearchControls();

        // Specify the search scope
        searchCtls.setSearchScope( SearchControls.SUBTREE_SCOPE );

        // Specify the attributes to return
        String returnedAtts[] = { MEMBER_FIELD };

        searchCtls.setReturningAttributes( returnedAtts );

        // Specify the LDAP search filter
        String searchFilter = "(&(objectClass=group)(CN=" + groupName + "))";

        // Search for objects using the filter
        NamingEnumeration<SearchResult> answer = ctxMap.get( configMap.get( GROUP ) ).search( configMap.get( SEARCHBASE ), searchFilter,
                searchCtls );

        SearchResult sr = null;


        // Loop through the search results
        while ( answer.hasMoreElements() ) {
            sr = (SearchResult) answer.next();
        }
        if ( sr == null  ) {
            return group;
        }

        // Create an attribute for memberOf
        javax.naming.directory.Attribute member = sr.getAttributes().get( MEMBER_FIELD );

        // Enumeration of all elements in memberOf
        NamingEnumeration<?> ne = member.getAll();


        // Loop though the enumeration, cut unwanted characters and add all
        // elements to User List
        while ( ne.hasMoreElements() ) {
            ...
        }

    }

So I want to pass the group's distinguished name as parameter to the function instead of the group's name and have the search made on that or get the attributes directly. Is this possible?

PS: this code is used to get the members of a certain group.

thank you

Answer 1

You don't need to search if you have the DN. Just look it up, with lookup().

Answer 2

With the help of EJP, I found out a way to get the attributes from the DistinguishedName without doing a search :

Attributes attrs;
attrs = ctx.getAttributes( dn );

Attribute attr= attrs.get( "the attribute you need" );