Spring Data JPA更新方法

Question

I'm still looking for a update method in Spring's Data JPA to update a given Object persited in a relational database. I only found solutions in which I'm forced to specify some kind of UPDATE queries via @Query annotation (in comparison with @Modifying), for example:

@Modifying
@Query("UPDATE User u SET u.firstname = ?1, u.lastname = ?2 WHERE u.id = ?3")
public void update(String firstname, String lastname, int id);

For building the Query, I also have to pass single parameters instead of whole Objects . But that's exactly what I want to do (passing whole Objects).

So, what I'm trying to find is a method like this:

public void update(Object obj);

Is it possible to build such a update method based on Spring Data JPA? How must it be annotated?

Thank you!

Answer 1

If the goal is to modify an entity, you don't need any update method. You get the object from the database, modify it, and JPA saves it automatically:

User u = repository.findOne(id);
u.setFirstName("new first name");
u.setLastName("new last name");

If you have a detached entity and want to merge it, then use the save() method of CrudRepository:

User attachedUser = repository.save(detachedUser);

Answer 2

If you want to update an Entity you do not need JPQL query(Optional). You can directly use (old version)findOne or (new version) findById to access data and make required modifications

Ex- here approve (entity ) is updated.

Optional<User> user= Repository.findById(id);
Registration reg = reg.get();       
reg.setApproved("yes");
userRepo.save(reg);

And That's It.