Spring Data JPA - 如何在检索后设置瞬态字段 [英] Spring Data JPA - how to set transient fields after retrieval

问题描述

使用Spring Data JPA的 JpaRepository 方法获取实体后，例如 findOne ， findBy ... 等等，我想知道什么是自动执行某些自定义的最佳方法代码，比如初始化一些瞬态字段。换句话说，假设我有一个用户实体，其中包含 fullName 临时字段，应该从数据库中提取后设置为 firstName 和 lastName 的串联，我应该怎么做首先，如果所有你想要的全名只是写一个方法，动态连接forename /姓氏。？？？？？？？？？？？？它不一定是一个字段。

如果您确实需要对实体加载进行一些处理，请注册一个 @PostLoad 实体生命周期回调：

  public class MyEntity {
 
 @PostLoad 
 //由实体负载框架调用。 
 public void doStuff（）{
 fullName = forename ++ surname; 
} 
 
 //替代
 public String getFullName（）{
 return forename ++ surname; 
} 
  

https://en.wikibooks.org/wiki/Java_Persistence/Advanced_Topics#Example_of_Entity_event_annotations

After an entity is fetched using the JpaRepository methods of Spring Data JPA, e.g. findOne, findBy..., etc., I was wondering what would be the best way to automatically execute some custom code, say to initialize some transient fields.

In other words, suppose I have a User entity with a fullName transient field, which should be set as a concatenation of firstName and lastName after fetching from the database, what should I do?

解决方案

Firstly, if all you want if full name just write a method that concatenates forename/surname on the fly. It doesn't have to be a field.

If you really need to do some processing on Entity load then register a @PostLoad entity lifecycle callback:

public class MyEntity{

     @PostLoad
     //invoked by framework on entity load.
     public void doStuff(){
         fullName =  forename + " " + surname;   
     }

     //alternative
     public String getFullName(){
         return forename + " " + surname;
     }

https://en.wikibooks.org/wiki/Java_Persistence/Advanced_Topics#Example_of_Entity_event_annotations

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