Question

我有这个问题：

 Exception in thread "main" javax.persistence.PersistenceException: [PersistenceUnit: fb-persistence] Unable to configure EntityManagerFactory
    at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:378)
    at org.hibernate.ejb.HibernatePersistence.createEntityManagerFactory(HibernatePersistence.java:56)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:48)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:32)
    at it.synclab.fb.test.Test.main(Test.java:13)
Caused by: java.lang.ClassCastException: org.hibernate.mapping.UnionSubclass cannot be cast to org.hibernate.mapping.RootClass
    at org.hibernate.cfg.annotations.PropertyBinder.bind(PropertyBinder.java:209)
    at org.hibernate.cfg.annotations.PropertyBinder.makePropertyValueAndBind(PropertyBinder.java:200)
    at org.hibernate.cfg.AnnotationBinder.processElementAnnotations(AnnotationBinder.java:2061)
    at org.hibernate.cfg.AnnotationBinder.processIdPropertiesIfNotAlready(AnnotationBinder.java:796)
    at org.hibernate.cfg.AnnotationBinder.bindClass(AnnotationBinder.java:707)
    at org.hibernate.cfg.Configuration$MetadataSourceQueue.processAnnotatedClassesQueue(Configuration.java:4008)
    at org.hibernate.cfg.Configuration$MetadataSourceQueue.processMetadata(Configuration.java:3962)
    at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1371)
    at org.hibernate.cfg.Configuration.buildMappings(Configuration.java:1348)
    at org.hibernate.ejb.Ejb3Configuration.buildMappings(Ejb3Configuration.java:1522)
    at org.hibernate.ejb.EventListenerConfigurator.configure(EventListenerConfigurator.java:193)
    at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:1100)
    at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:282)
    at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:366)
    ... 4 more

谁能帮我解决？我已经使用JPA配置了Hibernate，文件persistence.xml是：

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
             version="2.0">
    <persistence-unit name="fb-persistence" transaction-type="JTA">
        <provider>org.hibernate.ejb.HibernatePersistence</provider>
        <class>it.synclab.fb.jpa.Plugin</class>
        <properties>
            <property name="hibernate.dialect" value="org.hibernate.dialect.Oracle10gDialect"/>
            <property name="hibernate.hbm2ddl.auto" value="create-drop"/>  
            <property name="hibernate.connection.driver_class" value="oracle.jdbc.driver.OracleDriver"/>  
            <property name="hibernate.show_sql" value="true"/> 
            <property name="hibernate.connection.username" value="***"/>  
            <property name="hibernate.connection.password" value="***"/>
            <property name="hibernate.connection.url" value="jdbc:oracle:thin:@localhost:1521:RAFFAELE"/>
        </properties>
   </persistence-unit>
</persistence>

和我的类映射是：

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity @Table(name="PLUGIN")
public class Plugin {

    private int id;


    private String nome;


    private String descrizione;


    public Plugin(){}

    @Id
    @Column(name="ID")
    public int getId() {
        return id;
    }


    public void setId(int id) {
        this.id = id;
    }

    @Column(name="NOME")
    public String getNome() {
        return nome;
    }

    public void setNome(String nome) {
        this.nome = nome;
    }

    @Column(name="DESCRIZIONE")
    public String getDescrizione() {
        return descrizione;
    }

    public void setDescrizione(String descrizione) {
        this.descrizione = descrizione;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + id;
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Plugin other = (Plugin) obj;
        if (id != other.id)
            return false;
        return true;
    }
}

有什么问题？帮我？我忘了，我已经使用maven2配置了dependdenci，文件pom.xml是：

...
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>3.6.3.Final</version>
        </dependency>
       <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-validator</artifactId>
            <version>4.2.0.Final</version>
        </dependency>
...

由于

Answer 1

我敢打赌你的类路径上有多个hibernate jar，这就是为什么它会抛出一个类转换异常。

另一个看起来错误（但可能是正确的）是您正在使用JTA事务。如果您不知道JTA的含义，请将persistance.xml上的事务类型更改为transaction-type="RESOURCE_LOCAL"

Answer 2

我曾经在拥有彼此继承的Entity bean时遇到此错误。即使它们被核心注释（根据JPA2规范），它们也不适用于Hibernate（Hibernate JPA2实现存在许多此类错误）。最后我所做的是为鉴别器列（@DiscriminatorValue("SomeValue")）添加非常具体的（虽然从JPA2s观点来看不是强制性的）配置（通过注释），用于JOIN（@PrimaryKeyJoinColumn(name = "idColumn")）的列。从您的代码剪切后看来，您似乎没有使用继承，但如果您实际上是，请尝试使用。

此外，如果您的项目允许，请从Hibernate切换到Eclipselink作为JPA2实现。我有无数次出现，其中正确的JPA2代码在EclipseLink中运行良好，但在Hibernate中引发了bizzare异常。

JPA2和Hibernate的问题

2 个答案: