How to use "findBy" in an Entity with a Composite PK (Hibernate JPA)

Question

I am learning with bootspring.

findByDate(int date); used to work until I've moved int Date into the inner class.

Now I can save new entries but I can't retrive them byDate

What do I need to change?

@Transactional public interface ExpirationDAO extends JpaRepository<ExpirationDTO, Long> {      public ExpirationDTO findByDate(int date); } 

and

@Embeddable     public static class IdKey implements Serializable{         @NotNull         int date;         @ManyToOne         ProductDTO product;          public IdKey(){         }          //setters and getters     }     @EmbeddedId     private IdKey id;     @NotNull     int units;      public ExpirationDTO(){          }        //setters and getters } 

throws this exception:

org.springframework.data.mapping.PropertyReferenceException: No property date found for type ExpirationDTO! 

Answer 1

You should include name of embedded key class in repository instead of Long. Try this one (not tested):

public interface ExpirationDAO extends JpaRepository<ExpirationDTO, IdKey> {     public List<ExpirationDTO> findByIdDate(int date); } 

There after findBy Id is yours EmbeddedId and Date is attribute of embeddable class. And one more thing: if you use only part of embedded key, you can't expect only one result...

Answer 2

You should include name of embedded key class in repository and also add an underscore (_)

Tested below:

public interface ExpirationDAO extends JpaRepository<ExpirationDTO, IdKey> {     public List<ExpirationDTO> findByIdKey_Date(Date date); }