Spring 3.1 Hibernate 4继承异常 [无法强制转换为org.hibernate.mapping.RootClass]

Question

你好，我刚开始使用Spring、Hibernate4和Maven。基本上，我的类层次结构是HUmanMicroTask继承自MicroTask。在未来，可能会有几个其他类从MicroTask继承。我试图拥有一个表格对应一个具体类，这是使用Spring3和Hibernate4最简单的方法。然而，当我运行代码时，我一直收到以下异常：

13:11:52,260 ERROR TestContextManager:324 - Caught exception while allowing TestExecutionListener [org.springframework.test.context.support.DependencyInjectionTestExecutionListener@6ef137d] to prepare test instance [HumanMicroTaskBaseHibernateTest@52c05d3b]
java.lang.IllegalStateException: Failed to load ApplicationContext
    at org.springframework.test.context.TestContext.getApplicationContext(TestContext.java:157)
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:109)
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:75)
    at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:321)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:211)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:288)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:290)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in class path resource [database-config.xml]: Invocation of init method failed; nested exception is java.lang.ClassCastException: org.hibernate.mapping.UnionSubclass cannot be cast to org.hibernate.mapping.RootClass
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1455)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:567)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:913)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:464)
    at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:103)
    at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:1)
    at org.springframework.test.context.support.DelegatingSmartContextLoader.loadContext(DelegatingSmartContextLoader.java:228)
    at org.springframework.test.context.TestContext.loadApplicationContext(TestContext.java:124)
    at org.springframework.test.context.TestContext.getApplicationContext(TestContext.java:148)
    ... 24 more
Caused by: java.lang.ClassCastException: org.hibernate.mapping.UnionSubclass cannot be cast to org.hibernate.mapping.RootClass
    at org.hibernate.cfg.annotations.PropertyBinder.bind(PropertyBinder.java:212)
    at org.hibernate.cfg.annotations.PropertyBinder.makePropertyValueAndBind(PropertyBinder.java:203)
    at org.hibernate.cfg.AnnotationBinder.processElementAnnotations(AnnotationBinder.java:2013)
    at org.hibernate.cfg.AnnotationBinder.processIdPropertiesIfNotAlready(AnnotationBinder.java:768)
    at org.hibernate.cfg.AnnotationBinder.bindClass(AnnotationBinder.java:687)
    at org.hibernate.cfg.Configuration$MetadataSourceQueue.processAnnotatedClassesQueue(Configuration.java:3431)
    at org.hibernate.cfg.Configuration$MetadataSourceQueue.processMetadata(Configuration.java:3385)
    at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1337)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1727)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1778)
    at org.springframework.orm.hibernate4.LocalSessionFactoryBuilder.buildSessionFactory(LocalSessionFactoryBuilder.java:184)
    at org.springframework.orm.hibernate4.LocalSessionFactoryBean.afterPropertiesSet(LocalSessionFactoryBean.java:314)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1514)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1452)
    ... 38 more

虽然我看过很多论坛，但我仍然无法确定我的错误出在哪里。 我的MicroTask类如下：

@Entity
@Table(name = "MICROTASK")
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public class MicroTask {
    @Id
    @GeneratedValue(generator = "system-uuid")
    @GenericGenerator(name = "system-uuid", strategy = "uuid")
    @Column(name = "MICROTASKID")
    private String microTaskId;
    @Column(name = "CREATIONDATE")
    private Date creationDate;
    @Column(name = "DESCRIPTION")
    private String description;

    public Date getCreationDate() {
        return creationDate;
    }
//More Getters and setters 

我的HumanMicroTask类如下：

    @Entity
    @Table(name = "HUMANMICROTASK")
    @AttributeOverrides({
        @AttributeOverride(name="microTaskId", column=@Column(name="MICROTASKID")),
        @AttributeOverride(name="creationDate", column=@Column(name="CREATIONDATE")),
        @AttributeOverride(name="description", column=@Column(name="DESCRIPTION"))
    })
    public class HumanMicroTask extends MicroTask {


        @Column(name = "TITLE")
        private String title;
        @Column(name = "CHANNEL")
        private String channel;
        @Id
        @Column(name = "HMTID")
        private String humanMicroTaskid;

        public String getId() {
            return humanMicroTaskid;
        }
//More Getters and setters

我的 config.xml 如下：

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
        ">

    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"
        destroy-method="close">
        <property name="driverClass">
            <value>${jdbc.driver.className}</value>
        </property>
        <property name="jdbcUrl">
            <value>${jdbc.url}</value>
        </property>
        <property name="user">
            <value>${jdbc.username}</value>
        </property>
        <property name="password">
            <value>${jdbc.password}</value>
        </property>

    </bean>

    <bean id="sessionFactory"
        class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
        <property name="dataSource">
            <ref bean="dataSource"/>
        </property>
        <property name="packagesToScan" value="com.hp.hpl.crowdcloud" />
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect">${jdbc.hibernate.dialect}</prop>
                <prop key="hibernate.hbm2ddl.auto">create</prop>
                <!-- uncomment this for first time run -->
                <prop key="hibernate.hbm2ddl.auto">create</prop>
                <prop key="hibernate.show_sql">true</prop>
            </props>
        </property>
    </bean>
    <bean id="transactionManager"
        class="org.springframework.orm.hibernate4.HibernateTransactionManager">
        <property name="sessionFactory">
            <ref bean="sessionFactory" />
        </property>
    </bean>
    <tx:annotation-driven />

</beans>

我的Maven配置

    <maven.test.failure.ignore>true</maven.test.failure.ignore>
    <org.springframework.version>3.1.0.RELEASE</org.springframework.version>
    <hibernate.version>4.1.1.Final</hibernate.version>
    <sl4j.version>1.5.6</sl4j.version>

请帮我一下。我不确定我犯了什么错误。

- Raveesh Sharma

---

可能重复的问题 https://dev59.com/h07Sa4cB1Zd3GeqP6cjf - srikanth yaradla

Answer 1

这是由于两个类中都有Id列。请从HumanMicroTask中移除Id。

- dhamibirendra

---

你不需要从问题中删除代码的那一部分，现在它变得难以理解了。 - fledglingCoder

成功了！谢谢。为什么错误信息不像你的那么有启示性呢？ - Vinícius Fonseca

从子类中删除@Id注释已足够，或者您还可以删除字段、getter和setter，因为继承策略InheritanceType.TABLE_PER_CLASS要求您在子类表中使用与继承列完全相同的列名，因此映射可以从超类继承。其他继承策略可能需要您为每个子实体使用不同的ID列名称，因此@Id映射无法继承到子类并被显式声明。 - Vlastimil Ovčáčík

这是旧的，可能你已经不回答了，但是如果我的子类表也有一个标识列呢？ - Rig

@dhamibirendra 好的，如果我记得当时写这个代码时我的意思是他们自己的身份列。无论如何，我通过更明确地注释来解决了这个问题。 - Rig

Answer 2

修复此问题

从子类中删除@Id

在MicroTask中保留

   @Id
    @GeneratedValue(generator = "system-uuid")
    @GenericGenerator(name = "system-uuid", strategy = "uuid")
    @Column(name = "MICROTASKID")
    private String microTaskId;

在HumanMicroTask的子类中移除

   @Id
    @Column(name = "HMTID")
    private String humanMicroTaskid;

- nizar ouerghi

Answer 3

我之前也遇到过同样的问题。因为你的父类有一个名为 'Id' 的主键，在子类生成时，它们会自动生成一个与其父类主键名称完全相同的外键。

示例：（伪代码）

实体定义

父类：

  @Entity
    @Inheritance(strategy = InheritanceType.JOINED)
    @Table(name = "abstract_person", catalog = "catalog", schema = "")
    class AbstractPerson{

        //Primary Key
        @Id
        @Column(name = "idPerson")
        int idPerson;

        @Basic
        @Column(name = "name")
        String name;

        //corresponding getters and setters
    }

子类：

 @Entity
    @Table(name = "concrete_person", catalog = "catalog", schema = "")
    class ConcretePerson extends AbstractPerson{

       //No id or primary key is defined here

        @Basic
        @Column(name="profession")
        String profession;

    }

表格生成

父类将映射到此表：

表 "abstract_person"
id: Int （主键）
name: Varchar

子类将映射到此表：

表 "concrete_person"
profession: Varchar
idPerson: int（自动生成，作为外键连接父表和此表的主类）

//假设条件
Mysql数据库；
Jpa 2 Hibernate实现；
NetBeans 7x IDE

- José Roberto Ramírez Aguilar

Answer 4

对于TABLE_PER_CLASS层次结构，子类继承父类的唯一键，因此我们不应在子实体中提及唯一键约束。

移除主键注释，这对我很有效。

- VIrtual Host