Question

我正在尝试在Hibernate Framework中使用多对多关系，但我遇到了一些麻烦。

我有2个型号。

用户：

@Entity
public class User implements Serializable {
Long id;
String name;
List<Car> cars;
public User() {

}
public Long getId() {
    return id;
}
public void setId(Long id) {
    this.id = id;
}
public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}
public List<Car> getCars() {
    return cars;
}
public void setCars(List<Car> cars) {
    this.cars = cars;
}
}

汽车：

@Entity
public class Car implements Serializable {
Long id;
String mark;
public Car() {

}
public Long getId() {
    return id;
}
public void setId(Long id) {
    this.id = id;
}
public String getMark() {
    return mark;
}
public void setMark(String mark) {
    this.mark = mark;
}
}

我跟着这个page的线索，所以我的配置文件如下所示：

用户：

<hibernate-mapping>
<class name="com.bontade.phone_book.mvc.spring.models.User" table="USERS">
    <id name="id" type="java.lang.Long">
        <column name="ID" />
        <generator class="identity" />
    </id>        
    <property name="name" not-null="true" length="100" type="java.lang.String">
        <column name="NAME" />
    </property>       
    <list name="cars" table="USER_CAR" cascade="all">
        <key>
            <column name="USER_ID" />
        </key>
        <list-index></list-index>
        <many-to-many column="CAR_ID" class="com.bontade.phone_book.mvc.spring.models.Car" />
    </list>        
</class>
</hibernate-mapping>

汽车：

<hibernate-mapping>
<class name="com.bontade.phone_book.mvc.spring.models.Car" table="CARS">
    <id name="id" type="java.lang.Long">
        <column name="ID" />
        <generator class="identity" />
    </id>
    <property name="mark"  not-null="true" length="20" type="java.lang.String">
        <column name="MARK" />
    </property>     
</class>
</hibernate-mapping>

我收到错误：

    Hibernate: update CARS set MARK=? where ID=?
2011-02-23 16:32:34 org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [dispatcher] in context with path [/PhoneBook] threw exception [Request processing failed; nested exception is org.springframework.orm.hibernate3.HibernateOptimisticLockingFailureException: Batch update returned unexpected row count from update [0]; actual row count: 0; expected: 1; nested exception is org.hibernate.StaleStateException: Batch update returned unexpected row count from update [0]; actual row count: 0; expected: 1] with root cause
org.hibernate.StaleStateException: Batch update returned unexpected row count from update [0]; actual row count: 0; expected: 1
    at org.hibernate.jdbc.Expectations$BasicExpectation.checkBatched(Expectations.java:85)
    at org.hibernate.jdbc.Expectations$BasicExpectation.verifyOutcome(Expectations.java:70)
    at org.hibernate.jdbc.BatchingBatcher.checkRowCounts(BatchingBatcher.java:90)
    at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:70)
    at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:268)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:266)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:168)
    at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321)
    at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:50)
    at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1028)
    at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:366)
    at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:137)
    at org.springframework.orm.hibernate3.HibernateTransactionManager.doCommit(HibernateTransactionManager.java:655)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:732)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:701)
    at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:140)
    at com.bontade.phone_book.mvc.spring.models.dao.implementations.CarDAOImplementation.saveCar(CarDAOImplementation.java:30)
    at com.bontade.phone_book.mvc.spring.controllers.HomePageController.handleRequestInternal(HomePageController.java:43)
    at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:153)
    at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:48)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:875)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:807)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:571)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:501)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:306)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:96)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:244)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:108)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:558)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:379)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:243)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:259)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:281)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)

更新

public class CarAOImplementation implements CarDAO {

private HibernateTemplate hibernateTemplate;
private TransactionTemplate transactionTemplate;
public void setSessionFactory(SessionFactory sessionFactory) {
    this.hibernateTemplate = new HibernateTemplate(sessionFactory);
}
public void setTransactionTemplate(TransactionTemplate transactionTemplate) {
    this.transactionTemplate = transactionTemplate;
}

@Override
public void saveCar(final Car car) {
    // TODO Auto-generated method stub
    this.transactionTemplate.execute(new TransactionCallback() {

        public Object doInTransaction(TransactionStatus transactionStatus) {
            try {
                hibernateTemplate.saveOrUpdate(car);
            } catch (Exception e) {
                transactionStatus.setRollbackOnly();
            }
            return null;
        }
    });
}
...
}

更新2

Car markCar = new Car();
markCar.setId(null);
markCar.setMark("111");
carDAO.saveCar(markCar);

User mark = new User();
mark.setId(null);
mark.setName("mark");
List a = new ArrayList<Car>();
a.add(markCar);
mark.setCars(a);
userDAO.saveUser(mark);
List<User> users = userDAO.getAll();
System.out.println("==" + users.size() + "===");
System.out.println(users.get(0).getCars().get(0).getMark());

堆栈追踪：

    Hibernate: select user0_.ID as ID0_, user0_.NAME as NAME0_ from USERS user0_
==1==
2011-02-23 17:35:10 org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [dispatcher] in context with path [/PhoneBook] threw exception [Request processing failed; nested exception is org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.bontade.phone_book.mvc.spring.models.User.cars, no session or session was closed] with root cause
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.bontade.phone_book.mvc.spring.models.User.cars, no session or session was closed
    at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:380)
    at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:372)
    at org.hibernate.collection.AbstractPersistentCollection.readElementByIndex(AbstractPersistentCollection.java:173)
    at org.hibernate.collection.PersistentList.get(PersistentList.java:293)
    at com.bontade.phone_book.mvc.spring.controllers.HomePageController.handleRequestInternal(HomePageController.java:59)
    at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:153)
    at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:48)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:875)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:807)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:571)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:501)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:306)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:96)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:244)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:108)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:558)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:379)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:243)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:259)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:281)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)

Answer 1

不要手动设置CarId！

Car markCar = new Car();
markCar.setId(1L);  //<-- remove this line
markCar.setMark("111");
carDAO.saveCar(markCar);

删除此行，然后重试。

原因是hibernate使用主键值来确定它是否是未保存的实例（在正常情况下，NULL表示未保存）。所以我想将car id设置为一个值（不同的null）会让Hibernate感到困惑。

<强> ADDED

令我困惑的另一件事是你使用Annotations 和 XML。

Spring，Hibernate - 多对多 - 更新错误

1 个答案: