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JPA和EJB惰性初始化字段

[英]JPA and EJB lazy initialization fields

原文 2013-11-15 07:59:25 5 1 java/ jpa/ ejb/ lazy-initialization

I use jpa (eclipselink) + ejb(3) in my project, when i switch off transactions on ejb method there is a problem with a lazy loading. 我在项目中使用jpa（eclipselink）+ ejb（3），当我关闭ejb方法上的事务时，延迟加载存在问题。 If i try to Eager loading that's ok, but a it have more time to wait. 如果我尝试快速加载是可以的，但是它有更多时间等待。 How do you solve problems like that? 您如何解决这样的问题？ I think there are 2 methods: 我认为有2种方法：

Use the bean management transactions, and load the fields in that transactions (it's difficult because a lot of legacy code i have) 使用Bean管理事务，并在该事务中加载字段（这很困难，因为我拥有很多旧代码）
Use the eager initialization in entities. 在实体中使用急切的初始化。

Do you have any other ideas? 你还有其他建议吗？

Thank you! 谢谢！

1 个解决方案

Not a good idea 这不是一个好主意

2 .Eager loading is not a good idea too, because the risk to load the whole database into memory is really high. 2。提前加载也不是一个好主意，因为将整个数据库加载到内存的风险确实很高。

If its possible try to create (named)queries with fetch joins ( see http://www.kumaranuj.com/2013/07/jpa-2-fetch-joins-and-whether-we-should.html ) which only loads data you really need for further processing. 如果可能的话，尝试使用获取联接创建（命名）查询（请参阅http://www.kumaranuj.com/2013/07/jpa-2-fetch-joins-and-whether-we-should.html ），该查询仅会加载您确实需要进一步处理的数据。

JPA中惰性对象的奇怪初始化 - Strange initialization of lazy object in JPA

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Spring Data，JPA @ManyToOne懒惰初始化无法正常工作 - Spring Data, JPA @ManyToOne lazy initialization not working

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JPA 实体中延迟加载字段的侦听器 - Listener for lazy-loading fields in JPA entity

如何用JPA 2.0急切加载懒字段？ - How to eagerly load lazy fields with JPA 2.0?

使惰性初始化对象为 null，而 object 与 hibernate 代理在 ZF0B4A299C45171493AE3215D69 - Make Lazy initialization objects as null, while object is with hibernate proxy in jpa

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相关问题 JPA中惰性对象的奇怪初始化 - Strange initialization of lazy object in JPA 初始化集合时发生延迟初始化异常-JPA - Lazy Initialization Exception on Initialize a Collection - JPA Spring Data，JPA @ManyToOne懒惰初始化无法正常工作 - Spring Data, JPA @ManyToOne lazy initialization not working EJB 3 + JPA2 =具有空字段的反序列化对象 - EJB 3 + JPA2 = Deserialized Object with null fields JPA 实体中延迟加载字段的侦听器 - Listener for lazy-loading fields in JPA entity 如何用JPA 2.0急切加载懒字段？ - How to eagerly load lazy fields with JPA 2.0? 使惰性初始化对象为 null，而 object 与 hibernate 代理在 ZF0B4A299C45171493AE3215D69 - Make Lazy initialization objects as null, while object is with hibernate proxy in jpa Spring Rest JPA在创建json时需要忽略延迟初始化 - Spring rest JPA need to ignore lazy initialization when creating json “静态”字段的延迟初始化应“同步”-如何修复 - Lazy initialization of “static” fields should be “synchronized” - How to fix it 处理延迟加载的EJB JPA实体的JAX-WS代理对象的最佳方法是什么？ - What's the best way to deal with JAX-WS proxy objects for EJB JPA entities that are Lazy Loaded?

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