Dozer：Hibernate PersistentMap 未映射到 java.util.HashMap

发布于 2024-10-08 19:25:44 字数 714 浏览 3 评论 0原文

我有一个带有字段的 Hibernate 带注释的实体：

@OneToMany(mappedBy="templateInstance", fetch = FetchType.EAGER) 
@MapKey(name = "attributeName") 
private Map<String, Component> components;

Hibernate 从中创建了一个 PersistentMap。然后我希望 Dozer 将其映射到具有这样一个字段的对象：

private Map<String, ComponentDto> components;

在进行 LazyInitializationExceptions 和一些调试之后，我发现这不是关闭的 Hibernate 会话的问题，而是 Dozer 尝试不映射到 HashMap 但到持久映射！因此，当 Dozer 访问目标映射时，PersistentMap 会抛出异常，因为它当然没有会话。

所以，我认为 Dozer 的意图行为是映射到 HashMap。现在的问题是：我做错了什么还是 Dozer 以及如何让 Dozer 将 PersistentMap 映射到普通的 Java 标准映射？

我之前使用 List 时没有任何问题。还有其他人使用 Dozer 来映射 Hibernate PersistentMap 吗？

问候，孔苏米耶尔

原文

I have a Hibernate annotated entity with a field:

@OneToMany(mappedBy="templateInstance", fetch = FetchType.EAGER) 
@MapKey(name = "attributeName") 
private Map<String, Component> components;

Hibernate makes a PersistentMap out of this.
Then I want Dozer to map this to an object with such a field:

private Map<String, ComponentDto> components;

After having LazyInitializationExceptions and some debugging, I found out, that it´s not a problem of a closed Hibernate session, but that Dozer tries not to map to a HashMap but to a PersistentMap! And therefore when Dozer accesses the target map the PersistentMap throws the Exception, because it has no session of course.

So, I thought that the intented behaviour of Dozer is to map to a HashMap. Now the question: am I doing something wrong or Dozer and how can I get Dozer to map the PersistentMap to normal Java standard map?

I had no problems when using a List before. Has anybody else used Dozer for mapping Hibernate PersistentMap?

Regards,
Konsumierer

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听，心雨的声音 2024-10-15 19:25:44

我自己找到了解决方案。 DTO 中的 Components 字段必须如下所示：

HashMap<String, Component> components = new HashMap<String, Component>;

只有这样才能防止 Dozer 使用 PersistentMap 作为目标对象。

另一件重要的事情是为 DO 使用自定义 BeanMappingBuilder 来保存地图，如下所示：

public class TemplateInstanceMappingBuilder extends BeanMappingBuilder {

    @Override
    protected void configure() {

        mapping(TemplateInstance.class, TemplateInstanceDto.class)
            .fields("components", "components", FieldsMappingOptions.hintB(ComponentDto.class));

    }
}

有关该问题的更多信息，请参阅 Dozer 论坛 https://sourceforge.net/projects/dozer/forums/forum/452530/topic/4020856/index/page /1

I found the solution by myself. The components field in the DTO has to look like this:

HashMap<String, Component> components = new HashMap<String, Component>;

Only this way you can prevent Dozer from using the PersistentMap as the target object.

And the other important thing is to use a custom BeanMappingBuilder for the DO that holds the map and that looks like that:

public class TemplateInstanceMappingBuilder extends BeanMappingBuilder {

    @Override
    protected void configure() {

        mapping(TemplateInstance.class, TemplateInstanceDto.class)
            .fields("components", "components", FieldsMappingOptions.hintB(ComponentDto.class));

    }
}

For further information about that problem, see the Dozer forums at https://sourceforge.net/projects/dozer/forums/forum/452530/topic/4020856/index/page/1

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