blocks|key|4462907|text|我解决办法是使用@OneToMany创建额外的方法|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4462908|@OneToMany(cascade={},+fetch=FetchType.EAGER,+mappedBy="a")
public+Set+getBSet()+{};

@Transient
public+B+getB()+{+return+b.iterator().next();+}|code-block|syntax|javascript|4462909|我对这个解决方案不是很满意，但它是有效的，我找不到其他的方法。|4462910|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Workaround that work for me is create additional method with @OneToMany

<pre><code>@OneToMany(cascade={}, fetch=FetchType.EAGER, mappedBy="a")
public Set&lt;B&gt; getBSet() {};

@Transient
public B getB() { return b.iterator().next(); }
</code></pre>

I'm not very happy with this solutions, but it works and I can't find other way.

blocks|key|2387799|text|也可以尝试将@Cache注释放在getB()+getter上。我的观察是，如果缓存对象，它的关联可能不会被认为是缓存的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2387800|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Try putting @Cache annotation on getB() getter as well. My observations are that if you cache the object, it's associations may not be considered cached.

blocks|key|769299|text|这可能需要更多的工作，但您可以尝试使fetchType变得懒惰，并显式地执行B的获取。这样你就可以检查B的实例是否已经加载了？|type|unstyled|depth|inlineStyleRanges|entityRanges|data|769300|顺便说一句，你看过这篇文章吗？我认为问题是相似的：|769301|https://forum.hibernate.org/viewtopic.php?p=2378461|offset|length|769302|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|0|1F|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|Q|8|@]|9|@$F|R|G|S|1|T]]|A|$]]|$1|H|3|-4|5|6|7|U|8|@]|9|@]|A|$]]]|I|$J|$5|K|L|M|A|$N|E]]]]

It may be a little more work, but you could try making the fetchType Lazy, and
do the fetching of B explicitly. That way you could check whether the instance of B has already been loaded or not?

On a side note, have you seen this post? I think the problem is similar:

<a href="https://forum.hibernate.org/viewtopic.php?p=2378461" rel="nofollow">https://forum.hibernate.org/viewtopic.php?p=2378461</a>

blocks|key|2387896|text|我觉得最初的答案并没有完全涵盖为什么会发生这种情况。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2387897|为什么不缓存OneToOne+?|offset|length|style|BOLD|2387898|它没有被缓存，因为class+A不是关系的所有者，并且它的表中不包含@JoinColumn。因此，class+A无法分辨出什么是class+B的ID。这就是为什么当尝试检索class+A时，它需要向class+B发送一个查询，以确定类B的ID是什么，但是当它发送查询时，class+B已经加载，因此实际上不需要从缓存中检索它。|CODE|2387899|何时缓存OneToOne+?|2387900|现在，如果您从class+B导航到class+A的相反方向，那么您将直接命中缓存:)|2387901|为什么@OneToMany(cascade={}，fetch=FetchType.EAGER，mappedBy="a")有效?|2387902|在hibernate中，集合被缓存在称为集合缓存的专用区域中。Hibernate缓存组成集合的实体的主键。而不是实体本身；也就是说，在二级缓存中的某个地方没有存储任何集合。|2387903|一旦从集合缓存区域检索到的主键，它就会回退到常规实体缓存来检索实际的对象。因此，@OneToMany黑客为您工作。|2387904|entityMap^0|0|0|G|0|9|7|1D|7|1S|7|20|2|2E|7|2R|7|3R|7|0|0|E|0|7|7|H|7|0|0|1R|0|0|14|A|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|X|8|@$D|Y|E|Z|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|10|8|@$D|11|E|12|F|J]|$D|13|E|14|F|J]|$D|15|E|16|F|J]|$D|17|E|18|F|J]|$D|19|E|1A|F|J]|$D|1B|E|1C|F|J]|$D|1D|E|1E|F|J]]|9|@]|A|$]]|$1|K|3|L|5|6|7|1F|8|@$D|1G|E|1H|F|G]]|9|@]|A|$]]|$1|M|3|N|5|6|7|1I|8|@$D|1J|E|1K|F|J]|$D|1L|E|1M|F|J]]|9|@]|A|$]]|$1|O|3|P|5|6|7|1N|8|@$D|1O|E|1P|F|G]]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1Q|8|@]|9|@]|A|$]]|$1|S|3|T|5|6|7|1R|8|@$D|1S|E|1T|F|J]]|9|@]|A|$]]|$1|U|3|-4|5|6|7|1U|8|@]|9|@]|A|$]]]|V|$]]

I feel that the original answer does not cover entirly why this is happening.
Why OneToOne is not cached ?
It is not cached because <code>class A</code> is not the owner of the relationship and does not contain the @JoinColumn inside its table. Therefore there is no way for <code>class A</code> to tell what is the <code>ID</code> of <code>class B</code>. This is why when trying to retrieve <code>class A</code> it needs to send a query for <code>class B</code> to figure out what the ID of class B is, but when it sends the query the <code>class B</code> is already loaded so there is no need for it to actualy retrieve it from the cache.
When OneToOne will be cached ?
Now if you navigate the opposite way from <code>class B</code> to <code>class A</code> then you will hit the cache straight away :)
Why is @OneToMany(cascade={}, fetch=FetchType.EAGER, mappedBy=&quot;a&quot;) working ?
In hibernate collections are cached in their dedicated region known as collection cache. Hibernate caches the primary keys of the entities that make up the collection. Not the entities themselves; i.e. there is no Set stored somewhere in the second level cache.
Once the primary key for is retrieved from the collection cache region it falls back to the regular entity cache to retrieve the actual object. Therefore the <code>@OneToMany</code> hack works for you.

I have code like:

<pre><code>@Entity
@Table(name = "A")
@Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
public class A
{
 @OneToOne(cascade={CascadeType.ALL}, fetch=FetchType.EAGER, mappedBy="a")
 public B getB() {};
}

@Entity
@Table(name = "B")
@Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
public class B
{
 @OneToOne(cascade={}, fetch=FetchType.LAZY)
 @JoinColumn(name="A_ID")
 public A getA() {};
}
</code></pre>

each time when <code>A</code> is loaded there is query for <code>B</code>. Why is <code>A.getB()</code> not cached after <code>A</code> is loaded and is it possible to cache it?

Hibernate not caching my OneToOne relationship on the inverse side

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我的代码如下：@Entity@Table(name = "A")@Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)public class A{  @OneToOne(cascade={CascadeType.ALL}, fetch=FetchType.EAGER, mappedBy="a")  public B getB()

问Hibernate不在反面缓存我的OneToOne关系
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