@ElementCollection使用xml配置 [英] @ElementCollection using xml configuration

问题描述

我试图持久一个对象，其中有一组字符串到数据库，我发现我必须使用 @ElementCollection 这样做，但因为我使用 .hbm.xml 配置文件通过我的所有项目我想使用 xml 。
此问题 Hibernate，List< String> 显示了如何通过注释进行操作，此链接< a href =http://en.wikibooks.org/wiki/Java_Persistence/ElementCollection =nofollow> http://en.wikibooks.org/wiki/Java_Persistence/ElementCollection 提供了相关建议使用xml。但是当我试图使用< element-collection> 我的eclipse IDE不接受它，并给我一个错误的元素< class /> 表示元素类的内容必须匹配...

I'm trying to persist an Object which have a set of Strings to database, I found that I must use @ElementCollection to do that, but since I'm using .hbm.xml configuration files through all my project I want to do it using xml . this question Hibernate, List<String> shows how to do it through annotations, and this link http://en.wikibooks.org/wiki/Java_Persistence/ElementCollection provides tips to do it using xml. But when I tried to use <element-collection> my eclipse IDE didn't accept it and gave me an error at the element <class/> which says the contents of element class must match ...

我的类就像这样

public class Role {
private Long id;
private Integer version;
private String name;
private Set<String> menuItems;
/** getters and setters **/

Role.hbm.xml 如下所示：

and my Role.hbm.xml is like this:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="com.element.collection.beans">
    <class name="Role" table="Role">
    <id name="id" type="java.lang.Long" column="id">
        <generator class="org.hibernate.id.TableHiLoGenerator">
            <param name="table">HibernateUniqueKey</param>
            <param name="column">NexHiValue</param>
        </generator>
    </id>
<version name="version" column="Version" />
<property name="name" column="name" type="java.lang.String"
        not-null="true" length="128" />

 <element-collection name="menuItems">
<collection-table>menuItems</collection-table>
</element-collection>

</class>

这里是集合的最后一个映射，其余的不更改

here is the last mapping of the set, the rest is not changed

    <set name="menuItems" sort="unsorted" table="menuItems" lazy="false">
        <key column="itemId" />
        <element column="itemName" type="string" />
    </set>

推荐答案

检查文档：

• 7.2.3。基本类型和可嵌入对象的集合


• 7.3.1。已排序的集合

• 7.2.3. Collections of basic types and embeddable objects
• 7.3.1. Sorted collections

从该来源的示例：

<set name="aliases"
            table="person_aliases" 
            sort="natural">
    <key column="person"/>
    <element column="name" type="string"/>
</set>

因此答案是< element>

• 示例7.16。 < element> 使用映射文件对集合值进行标记

< element> 可用于任何类型的集合映射，例如< bag> < set> < list> ...

This <element> could be used in any type of colleciton mapping, like <bag> <set> <list>...

可能很有趣： Understading对于在hibernate中收集依赖对象的限制 ...

Also could be interesting: Understading the restrictions for collection of dependent objects in hibernate ...

根据更多细节，我们可以说，这里的映射将是：

Based on more details, we could say, that the mapping here would be like:

<class name="Role" table="Role">
    ...

    <set name="menuItems" sort="unsorted" table="menuItems" lazy="false">
        <key column="menuId" /> // not itemId
        <element column="itemName" type="string" />
    </set>
</class>

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