Hibernate @LazyCollection注解的用处是什么？ [英] What is the use of the Hibernate @LazyCollection annotation

问题描述

我有2个实体作为Parent和Child作为OneToMany关系作为

  @Entity 
 public class Parent {
 
 @Id 
 @GeneratedValue（strategy = GenerationType.AUTO）
 private Integer id; 
 
私人字符串名称; 
 
 @OneToMany（mappedBy =parent，fetch = FetchType.LAZY）
 @IndexColumn（name =index，base = 1）
 @Cascade（org.hibernate .annotations.CascadeType.ALL）
 @LazyCollection（LazyCollectionOption.EXTRA）
 private List< Child> childs = new ArrayList< Child>（）; 
 // getter and setter 
 
} 
  

是使用 @LazyCollection（LazyCollectionOption.EXTRA），它会在什么时候出现在图片中，比如哪个子列表的操作，会有好处？

解决方案

为了给你一个提示，主要是出于性能原因，你可以开始阅读以下链接：

<第二级缓存

Hibernate文档

I have 2 entities as Parent and Child as OneToMany relation as

@Entity
public class Parent {

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Integer id;

private String name;

@OneToMany(mappedBy = "parent", fetch = FetchType.LAZY)
@IndexColumn(name = "index", base = 1)
@Cascade(org.hibernate.annotations.CascadeType.ALL)
@LazyCollection(LazyCollectionOption.EXTRA)
private List<Child> childs = new ArrayList<Child>();
// getter and setter

}

So here what is use of @LazyCollection(LazyCollectionOption.EXTRA) and when does it will come in picture, like for which operation with child list, it will be beneficial ?

解决方案

To give you a hint, it's mainly for performance reasons, you can start reading the following links:

Second Level Cache

Hibernate Documentation

这篇关于Hibernate @LazyCollection注解的用处是什么？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！