声明的元模型属性工作正常BUT继承元模型属性是NULL。为什么？ [英] Declared metamodel attributes work fine BUT Inherited Metamodel Attributes are NULL. Why?
问题描述
我无法执行以下测试： -
@Test
public void test（）{
EntityManager em = entityManagerFactory.createEntityManager（）;
em.getTransaction（）。begin（）;
CriteriaBuilder builder = em.getCriteriaBuilder（）;
CriteriaQuery< Project> query = builder.createQuery（Project.class）;
根< Project> project = query.from（Project.class）;
路径< String> name = project.get（Project_.name）;
Assert.assertNotNull（name）;
路径< EntityLifeCycleImpl> lifeCycle = project.get（Project_.lifeCycle）; //问题在这里，抛出NullPointer
Assert.assertNotNull（lifeCycle）;
}
它会在 project.get（Project_）中抛出NullPointerException。 lifeCycle）行。为什么？
java.lang.NullPointerException $ b $ org.hibernate.ejb.criteria.path.AbstractPathImpl.get（ AbstractPathImpl.java:138）
PersistenceEntityBase.java
import org.hibernate.annotations.GenericGenerator;
@MappedSuperclass
@Access（AccessType.PROPERTY）
public abstract class PersistentEntityBase {
protected String identifier;
protected EntityLifeCycleImpl lifeCycle = new EntityLifeCycleImpl（）;
保护PersistentEntityBase（）{
}
@Id
@GeneratedValue（generator =generator）
@GenericGenerator（name = generator，strategy =guid，parameters = {}）
@Column（name =identifier）
public String getIdentifier（）{
return identifier;
}
public void setIdentifier（String identifier）{
this.identifier = identifier;
}
@Embedded
public EntityLifeCycleImpl getLifeCycle（）{
return lifeCycle;
}
public void setLifeCycle（EntityLifeCycleImpl lifeCycle）{
this.lifeCycle = lifeCycle;
}
}
Project.java
@Entity
@Table（name =project）
@Access（AccessType.PROPERTY）
public class Project extends PersistentEntityBase {
private String name;
protected Project（）{
}
public Project（String name）{
this（）;
this.name = name;
@Column（name =name，nullable = false，unique = true）
public String getName（）{
return name;
}
public void setName（String name）{
this.name = name;
}
}
EntityLifeCycleImpl.java
@Embeddable
public class EntityLifeCycleImpl implements EntityLifeCycle {
私人字符串createdBy;
私人日期createdDate;
@Column（name =created_by）
public String getCreatedBy（）{
return createdBy;
}
public void setCreatedBy（String createdBy）{
this.createdBy = createdBy;
@Column（name =created_date）
public Date getCreatedDate（）{
return createdDate;
}
public void setCreatedDate（Date createdDate）{
this.createdDate = createdDate;
}
}
PersistentEntityBase_.java （使用Hibernate Metamodel Generator生成）
@StaticMetamodel（PersistentEntityBase.class）
public abstract class PersistentEntityBase_ {
public static volatile SingularAttribute< PersistentEntityBase，EntityLifeCycleImpl>生命周期;
public static volatile SingularAttribute< PersistentEntityBase，String>标识符;
Project_.java
@StaticMetamodel（Project.class）
public abstract class Project_ extends PersistentEntityBase_ {
public static volatile SingularAttribute< Project，String>名称;
}
EntityLifeCycleImpl_.java
@StaticMetamodel（EntityLifeCycleImpl.class）
public abstract class EntityLifeCycleImpl_ {
public static volatile SingularAttribute< EntityLifeCycleImpl，String>由...制作;
public static volatile SingularAttribute< EntityLifeCycleImpl，Date>创建日期;
persistence.xml （仅限relavent部分）
< class> com.comp.timetracking.entity.PersistentEntityBase< / class>
< class> com.comp.timetracking.entity.Project< / class>
编辑：
我使用hibernate-entitymanager.3.6。 0.Final和hibernate-jpamodelgen.1.0.0.Final。
编辑2
@Pascal
我认为Hibernate EM 3.6.0.Final允许我们在 @Entity 级别定义 @Embedded 注释字段，但是它在 @MappedSuperclass 级别拒绝这样的字段。你说什么？
因为我在这里看不到文件上传选项，所以我在我的esnips帐户中上传了TestCase。 下载基于maven的 - 项目并运行 SingularAttributeTest.java 。并检出控制台输出
ERROR main metamodel.MetadataContext：413 - 无法找到静态元模型字段：timetracking.entity.Employee_＃ lifeCycle
点击下载embedded-singular-attribute.zip 链接无需安装下载管理器即可下载文件。 （如果你点击使用绿色箭头下载链接，你必须安装下载管理器!!）
我使用EclipseLink测试了您的类和测试用例（我删除了Hibernate特定的部分）并通过了测试。但是，Hibernate 3.5.6确实失败了。看起来像Hibernate中的一个bug。顺便说一下，在<$ c中缺少一个 Temporal 注释$ c $>可嵌入
@Column（name =created_date）
@Temporal （TemporalType.DATE）
public Date getCreatedDate（）{
return createdDate;
}
你不应该声明 PersistentEntityBase 在 persistence.xml 中（映射的超类不是实体）。
I am not able to run the following test:-
@Test
public void test() {
EntityManager em = entityManagerFactory.createEntityManager();
em.getTransaction().begin();
CriteriaBuilder builder = em.getCriteriaBuilder();
CriteriaQuery<Project> query = builder.createQuery(Project.class);
Root<Project> project = query.from(Project.class);
Path<String> name = project.get(Project_.name);
Assert.assertNotNull(name);
Path<EntityLifeCycleImpl> lifeCycle = project.get(Project_.lifeCycle); // problem is here, throws NullPointer
Assert.assertNotNull(lifeCycle);
}
it throws NullPointerException at project.get(Project_.lifeCycle) line. Why?
java.lang.NullPointerException
at org.hibernate.ejb.criteria.path.AbstractPathImpl.get(AbstractPathImpl.java:138)
PersistenceEntityBase.java
import org.hibernate.annotations.GenericGenerator;
@MappedSuperclass
@Access(AccessType.PROPERTY)
public abstract class PersistentEntityBase {
protected String identifier;
protected EntityLifeCycleImpl lifeCycle = new EntityLifeCycleImpl();
protected PersistentEntityBase() {
}
@Id
@GeneratedValue(generator="generator")
@GenericGenerator(name="generator", strategy="guid", parameters = {})
@Column(name="identifier")
public String getIdentifier() {
return identifier;
}
public void setIdentifier(String identifier) {
this.identifier = identifier;
}
@Embedded
public EntityLifeCycleImpl getLifeCycle() {
return lifeCycle;
}
public void setLifeCycle(EntityLifeCycleImpl lifeCycle) {
this.lifeCycle = lifeCycle;
}
}
Project.java
@Entity
@Table(name="project")
@Access(AccessType.PROPERTY)
public class Project extends PersistentEntityBase {
private String name;
protected Project() {
}
public Project(String name) {
this();
this.name = name;
}
@Column(name="name", nullable=false, unique=true)
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
EntityLifeCycleImpl.java
@Embeddable
public class EntityLifeCycleImpl implements EntityLifeCycle {
private String createdBy;
private Date createdDate;
@Column(name="created_by")
public String getCreatedBy() {
return createdBy;
}
public void setCreatedBy(String createdBy) {
this.createdBy = createdBy;
}
@Column(name="created_date")
public Date getCreatedDate() {
return createdDate;
}
public void setCreatedDate(Date createdDate) {
this.createdDate = createdDate;
}
}
PersistentEntityBase_.java (Generated using Hibernate Metamodel Generator)
@StaticMetamodel(PersistentEntityBase.class)
public abstract class PersistentEntityBase_ {
public static volatile SingularAttribute<PersistentEntityBase, EntityLifeCycleImpl> lifeCycle;
public static volatile SingularAttribute<PersistentEntityBase, String> identifier;
}
Project_.java
@StaticMetamodel(Project.class)
public abstract class Project_ extends PersistentEntityBase_ {
public static volatile SingularAttribute<Project, String> name;
}
EntityLifeCycleImpl_.java
@StaticMetamodel(EntityLifeCycleImpl.class)
public abstract class EntityLifeCycleImpl_ {
public static volatile SingularAttribute<EntityLifeCycleImpl, String> createdBy;
public static volatile SingularAttribute<EntityLifeCycleImpl, Date> createdDate;
}
persistence.xml (only relavent part)
<class>com.comp.timetracking.entity.PersistentEntityBase</class>
<class>com.comp.timetracking.entity.Project</class>
EDIT: I use hibernate-entitymanager.3.6.0.Final and hibernate-jpamodelgen.1.0.0.Final.
EDIT 2
@Pascal
I think Hibernate EM 3.6.0.Final allows us to define @Embedded annotated field at @Entity level but it denies such field at @MappedSuperclass level. What do you say?
As I cannot see "file upload option" here, I've uploaded the TestCase in my esnips account. Download the maven-based-project and run SingularAttributeTest.java. And checkout the console output
ERROR main metamodel.MetadataContext:413 - Unable to locate static metamodel field : timetracking.entity.Employee_#lifeCycle
Click on "Download embedded-singular-attribute.zip" link to download the file WITHOUT installing the download manager. (If you click on Download link with Green arrow, you'll have to install the download manager!!)
I tested your classes and test case with EclipseLink (I removed the Hibernate specific parts) and the test passes. But it indeed fails with Hibernate 3.5.6. Looks like a bug in Hibernate.
By the way, you are missing a Temporal annotation in your Embeddable
@Column(name = "created_date")
@Temporal(TemporalType.DATE)
public Date getCreatedDate() {
return createdDate;
}
And you are not supposed to declare PersistentEntityBase in the persistence.xml (a mapped super class is not an entity).
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