我使用Netbeans 8.0.1创建了两个Maven项目来说明一个问题:common1和common2(罐子)。

common1:

软件包pck1

@MappedSuperclass
public class Entity1 implements Serializable {
    @Basic(optional = false)
    @Column(name = "val")
    protected String val;
}


软件包pck2

@Entity
@Table(name = "entity2")
public class Entity2 extends Entity1 {
    @Id
    private Long id;
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
}


persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
  <persistence-unit name="PU-1" transaction-type="RESOURCE_LOCAL">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
    <exclude-unlisted-classes>false</exclude-unlisted-classes>
  </persistence-unit>
</persistence>


pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.ent</groupId>
    <artifactId>common1</artifactId>
    <version>1.0</version>
    <packaging>jar</packaging>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.7</maven.compiler.source>
        <maven.compiler.target>1.7</maven.compiler.target>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.eclipse.persistence</groupId>
            <artifactId>eclipselink</artifactId>
            <version>2.5.2</version>
        </dependency>
        <dependency>
            <groupId>org.eclipse.persistence</groupId>
            <artifactId>org.eclipse.persistence.jpa.modelgen.processor</artifactId>
            <version>2.5.2</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>
</project>


common2

软件包pck3

@Entity
@Table(name = "entity3")
public class Entity3 extends Entity1 {
    @Id
    private Long id;
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
}


persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
    <persistence-unit name="PU-2" transaction-type="RESOURCE_LOCAL">
        <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
        <exclude-unlisted-classes>false</exclude-unlisted-classes>
    </persistence-unit>
</persistence>


pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.ent</groupId>
    <artifactId>common2</artifactId>
    <version>1.0</version>
    <packaging>jar</packaging>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.7</maven.compiler.source>
        <maven.compiler.target>1.7</maven.compiler.target>
    </properties>
    <dependencies>
        <dependency>
            <groupId>com.ent</groupId>
            <artifactId>common1</artifactId>
            <version>1.0</version>
        </dependency>
        <dependency>
            <groupId>org.eclipse.persistence</groupId>
            <artifactId>eclipselink</artifactId>
            <version>2.5.2</version>
        </dependency>
        <dependency>
            <groupId>org.eclipse.persistence</groupId>
            <artifactId>org.eclipse.persistence.jpa.modelgen.processor</artifactId>
            <version>2.5.2</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>
</project>


构建过程完成后,我在Netbeans中看到了具有规范元模型的生成源:

common1

软件包pck1

@Generated(value="EclipseLink-2.5.2.v20140319-rNA", date="2014-11-11T13:39:25")
@StaticMetamodel(Entity1.class)
public class Entity1_ {

    public static volatile SingularAttribute<Entity1, String> val;

}


软件包pck2

@Generated(value="EclipseLink-2.5.2.v20140319-rNA", date="2014-11-11T13:39:25")
@StaticMetamodel(Entity2.class)
public class Entity2_ extends Entity1_ {

    public static volatile SingularAttribute<Entity2, Long> id;

}


common2

软件包pck3

@Generated(value="EclipseLink-2.5.2.v20140319-rNA", date="2014-11-11T13:39:31")
@StaticMetamodel(Entity3.class)
public class Entity3_ {

    public static volatile SingularAttribute<Entity3, Long> id;

}


问题是,为什么Entity3_不将Entity1_扩展为Entity2_?我究竟做错了什么?

最佳答案

我有同样的问题。这似乎是我使用的Eclipse Link 2.5.0.v20130507库中的错误。由于我在JBoss中使用了hibernate,因此我切换到了Hibernate 4.3.8。使用hibernate-jpamodelgen库可以正确生成元模型类。

09-05 18:35