Spring JPA-持久化嵌套对象
我有一个简单的JPA存储库,如下所示:Spring JPA-持久化嵌套对象,spring,jpa,spring-data-jpa,repository,Spring,Jpa,Spring Data Jpa,Repository,我有一个简单的JPA存储库,如下所示: public interface UserRepository extends JpaRepository<User, String> { User findByName(String name); } @Entity public class User { @Id @GeneratedValue(generator = "uuid") @GenericGenerator(name = "uuid", stra
public interface UserRepository extends JpaRepository<User, String>
{
User findByName(String name);
}
@Entity
public class User
{
@Id
@GeneratedValue(generator = "uuid")
@GenericGenerator(name = "uuid", strategy = "uuid2")
protected String uuid;
@Column(nullable = false, unique = true)
private String name;
@Column(nullable = false)
private String email;
@OneToOne(fetch = FetchType.EAGER, cascade = CascadeType.ALL, mappedBy = "user")
private PlayerCharacter playerCharacter;
//...
}
User user = userRepository.findByName("Alice");
PlayerCharacter character = user.getPlayerCharacter();
character.setCharacterName("ConanTheBarbarian");
userRepository.save(user);
现在,我知道我可以很容易地编辑和保存这样的用户实例:
public interface UserRepository extends JpaRepository<User, String>
{
User findByName(String name);
}
@Entity
public class User
{
@Id
@GeneratedValue(generator = "uuid")
@GenericGenerator(name = "uuid", strategy = "uuid2")
protected String uuid;
@Column(nullable = false, unique = true)
private String name;
@Column(nullable = false)
private String email;
@OneToOne(fetch = FetchType.EAGER, cascade = CascadeType.ALL, mappedBy = "user")
private PlayerCharacter playerCharacter;
//...
}
User user = userRepository.findByName("Alice");
PlayerCharacter character = user.getPlayerCharacter();
character.setCharacterName("ConanTheBarbarian");
userRepository.save(user);
但是,在没有指向用户
实例的指针的上下文中,如何持久化玩家角色
实例,f.I.:
public void changePlayerCharacterName(PlayerCharacter character, String name){
character.setCharacterName(name);
// How to correctly persist the 'character' instance here?
}
我可以直接调用userRepository.save(字符)吗代码>
我是否需要自动连接另一个存储库(PlayerCharacterRepository
)并对其调用.save()?首先,您不会使用UserRepository,而是使用PlayerCharacterRepository
但即便如此,JPA的基本原则是,它自动使对受管实体所做的更改保持不变。因此,您不需要调用save()。您只需获取一个托管玩家角色(使用find(),或通过关联导航,或使用查询),然后更改其名称。这就是您所需要的。以这种方式进行双向映射
@OnetoOne
@LazyCollection(LazyCollectionOption.FALSE)
private PlayerCharacter playerCharacter;
@OneToOne(fetch=FetchType.EAGER)
private Status status;
通过这种类型的映射,您可以同时使用UserRepository和PlayerCharacterRepository来持久化这两个实例。如果海报不是JPA的一部分,您为什么建议海报使用一些专有注释@LazyCollection
?!通过这种方式,您可以进行双向映射。假设所有这些都发生在一个事务userRepository中。保存是多余的。