在 spring 数据 jpa 中禁用自动更新 [英] Disable auto update in spring data jpa

问题描述

我有一个 JPA @Entity 类.我使用 jpa 的 findBy 方法之一检索实体，JPA 会认为该方法处于 persistent state，然后我更新了一些实体中的字段，然后将实体传递给验证.如果验证失败，则不更新，如果验证成功则持久化实体.

I have a JPA @Entity class. I retrieve the entity using one of the jpa's findBy methods which would be considered by JPA to be in the persistent state, then I update some of the fields in the entity, then pass the entity to validation. If the validation fails, then don't update, if validation succeeds then persist the entity.

这里是这个流程的主要问题:因为我更新了实体以便在验证中使用它，我是否调用 save() 无关紧要，记录将始终更新因为 JPA 检测到实体已更改并将其标记为更新.

Here is the main issue with this flow: because I updated the entity for it to be used in the validation, it does not matter whether I call save(), the record will always be updated because JPA detects that the entity has been changed and flags it for an update.

如何避免这种行为?

我的实体类

@Entity
@Table( name = "user" )
@Data
@EqualsAndHashCode( of = { "id" } )
@ToString( of = { "id" } )
public class UserModel {

@Id
@GeneratedValue( strategy = GenerationType.AUTO )
@Column( name = "u_id" )
private Long id;

@Column( name = "u_first_name" )
private String firstName;

@Column( name = "u_last_name" )
private String lastName;

@Column( name = "u_email_id" )
private String emailId;

@Column( name = "u_password" )
private String password;

@Column( name = "u_mobile_number" )
private String mobileNumber;

@Column( name = "u_created_at" )
private Calendar createdAt;

@Column( name = "u_is_active" )
private Boolean isActive;
}

推荐答案

我看到两个选项:

1. 当验证失败时，从 EntityManager 分离实体.

确保使用适当的级联注释或手动遍历所有需要分离的实体.

Make sure that you use appropriate cascade annotations or manually iterate through all entities that need detaching.

在分离模式下执行整个更新和验证，即在没有 @Transactional 注释的方法中.这样，只有当您明确调用 save 时，信息才会被存储.

Do the whole update and validation in detached mode, i.e. in a method without @Transactional annotation. This way only when you explicitly call save the information will get stored.

这可能有点简单，但缺点是两次加载所有受影响的实体.

This might be a little simple to get right but has the drawback of loading all the affected entities twice.

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