Java：如何将 Hibernate 命名 SQL 查询（在 XML 文件中）的结果映射到带注释的实体
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Java: How to map results of Hibernate Named SQL Query (in XML file) to an annotated Entity
提问by Shaun Scovil
I'm trying to map the results of a Hibernate Named SQL Query (stored in an XML file) to an annotated Entity object. I've read through countless docs and tutorials and support threads but I still can't seem to get it working.
我正在尝试将 Hibernate 命名 SQL 查询（存储在 XML 文件中）的结果映射到带注释的实体对象。我已经阅读了无数的文档和教程以及支持线程，但我似乎仍然无法让它工作。
Here's what I've got so far...
这是我到目前为止所得到的......
In my persistence.xmlfile, I've declared a mapping file called test.xml, and in test.xmlI've got the following:
在我的persistence.xml文件中，我声明了一个名为 的映射文件test.xml，其中test.xml包含以下内容：
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<sql-query name="Asset.Test">
<![CDATA[ SELECT a.id, a.name FROM assets a WHERE a.id = 1 ]]>
</sql-query>
</hibernate-mapping>
This works fine for retrieving results in a generic Object, using this code:
这适用于检索通用对象中的结果，使用以下代码：
Object entity = session.getNamedQuery("Asset.Test").list().get(0);
But when I try to map these results to annotated Entity object, I keep getting an exception Caused by: org.hibernate.HibernateException: Errors in named queries: Asset.Test.
但是当我尝试将这些结果映射到带注释的 Entity 对象时，我不断收到异常Caused by: org.hibernate.HibernateException: Errors in named queries: Asset.Test。
Here is my Entity:
这是我的实体：
import javax.persistence.Entity;
import javax.persistence.Id;
import java.io.Serializable;
import java.math.BigInteger;
@Entity
public class AssetTestEntity implements Serializable {
private static final long serialVersionUID = 1L;
@Id
private BigInteger id;
private String name;
public BigInteger getId() {
return id;
}
public void setId(BigInteger id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
And here is my modified Named Query:
这是我修改后的命名查询：
<sql-query name="Asset.Test">
<return alias="assets" class="AssetTestEntity" />
<![CDATA[ SELECT assets.id AS {assets.id}, assets.name AS {assets.name} FROM assets WHERE assets.id = 1 ]]>
</sql-query>
I've tried several variations of this, with and without the curly braces, using different aliases, etc.
我已经尝试了几种变体，有和没有花括号，使用不同的别名等。
I've RTFM, including this: http://docs.jboss.org/hibernate/stable/core.old/reference/en/html/querysql-namedqueries.html
我有 RTFM，包括这个：http: //docs.jboss.org/hibernate/stable/core.old/reference/en/html/querysql-namedqueries.html
I've seen dozens of examples like this: http://examples.javacodegeeks.com/enterprise-java/hibernate/hibernate-named-query-example/
我见过很多这样的例子：http: //examples.javacodegeeks.com/enterprise-java/hibernate/hibernate-named-query-example/
Can anyone see what I'm doing wrong here? Do you have to define the entity in XML as well?
谁能看到我在这里做错了什么？您是否也必须在 XML 中定义实体？
Thanks in advance!
提前致谢！
UPDATE
更新
I did manage to get it to work by defining the Entity class in the XML file, in addition to having the Entity object. The working mapping XML looks like this:
除了拥有 Entity 对象外，我确实通过在 XML 文件中定义 Entity 类来使其工作。工作映射 XML 如下所示：
<hibernate-mapping>
<class name="com.asset.AssetTestEntity" table="assets">
<id name="id" type="java.math.BigInteger">
<column name="id" />
<generator class="identity" />
</id>
<property name="name" type="string">
<column name="name" />
</property>
</class>
<sql-query name="Asset.Test">
<return alias="assets" class="com.asset.AssetTestEntity" />
<![CDATA[ SELECT a.id, a.name FROM assets a WHERE a.id = 1 ]]>
</sql-query>
</hibernate-mapping>
I was hoping Hibernate could handle just using the annotated Entity without having to do this, but apparently not. I even tried adding @Column annotations to the entity...
我希望 Hibernate 可以只使用带注释的实体而不必这样做，但显然不是。我什至尝试向实体添加@Column 注释...
采纳答案by Marcel St?r
The fact that it works if you define the OR mapping alongside the named query in the mapping files leads to a simple conclusion (for me): Hibernate doesn't know about your @Entityannotated class.
如果您在映射文件中的命名查询旁边定义 OR 映射，它会起作用这一事实导致一个简单的结论（对我而言）：Hibernate 不知道您的带@Entity注释的类。
Make sure the persistence.xmllists your entity classes.
确保persistence.xml列出您的实体类。
回答by Wayne Baylor
Hibernate can also automatically populate beans from query results:
Hibernate 还可以从查询结果中自动填充 bean：
List<AssetTestEntity> results = session.getNamedQuery("Asset.Test")
.setResultTransformer(Transformers.aliasToBean(AssetTestEntity.class))
.list();
However the results are not "managed" like non-native query results.
然而，结果不像非本地查询结果那样“受管理”。
