Is there a way to get all the labels for a node in SDN 4.0

问题

I want to get all the labels belongs to a node, if there a way to do this in one query in SDN 4.0?

For example, my current repo is like

Book findById(Long bookId);

@Query("MATCH (n:Book) where id(n)={0} set n:AnotherLabel return n")
Book updateBookLabel(Long bookId);

is there anyway I can simply

book.getLabels();

to retrieve all the labels for this book node.

the class for book is

@NodeEntity
public class Book extends Something {
}

Yes, by default, my Book node should has two label Book and Something.Since I have a update method in the repo to add another label. Anyway I can retrieve the book with all 3 labels?

Thanks

回答1:

The only way to do this is via a custom query -

@Query("MATCH (n:Book) where id(n)={0} return labels(n) as labels")
List<String> getBookLabels(Long bookId);

(untested)

Update based on comment

To return labels and the node properties in a single query, use a @QueryResult-

SDN 4.0 (cannot map nodes and relationships from a custom query to domain entities in a query result):

@QueryResult
public class BookResult {
    Long id;
    Map<String,Object> node;
    List<String> labels;
 }

@Query("MATCH (n:Book) where id(n)={0} return labels(n) as labels, ID(n) as id, {properties: n} as node")
BookResult getBookLabels(Long bookId);

SDN 4.1

 @QueryResult
 public class BookResult {
      Book node;
      List<String> labels;
 }

 @Query("MATCH (n:Book) where id(n)={0} return labels(n) as labels, n as node")
 BookResult getBookLabels(Long bookId);

回答2:

Yes it is possible here is a working example

Entity

public class Book {
  @Labels
  Set<String> labels= new HashSet<>();
  private Long id;
}

Repo

public interface BookRepository extends GraphRepository<Book> 
{
}

That var labels will contain all labels of a node, because it is annotated with @Label, so you can do book.getlabel() or even setLabel() when you want, if you want.

I used spring boot 1.4.0 and neo4j community 3.0.4 for this example.

来源：https://stackoverflow.com/questions/35978001/is-there-a-way-to-get-all-the-labels-for-a-node-in-sdn-4-0