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我正在使用休眠站点上的 hibernate_reference.pdf 使用休眠多对多关联。我正在使用文档中描述的相同实体 Event.java 和 Person.java。

我看到许多人面临“无法初始化集合异常”并且许多人解决了这个问题，但堆栈溢出帖子中提到的解决方案都没有解决我的问题。可能是这些解决方案不适用于多对多关联，或者我的配置有问题。以下是我的 hbm.xml 文件：

事件.hbm.xml：

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC 
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="roseindia.tutorial.hibernate">
    <class name="Event" table="EVENTS">

        <id name="id" column="EVENT_ID">
            <generator class="native" />
        </id>

        <property name="date" type="timestamp" column="EVENT_DATE" />
        <property name="title" type="string" />
        <property name="location" type="string" column="LOC" />

        <set name="participants" table="PERSON_EVENT" inverse="true" lazy="false" cascade="all" >
            <key column="EVENT_ID" not-null="true" />
            <many-to-many column="PERSON_ID" class="Person" />
        </set>
    </class>
</hibernate-mapping>

事件.java

public class Event implements java.io.Serializable {
    private long id;
    private String title;
    private Date date;
    private String location;

    public Event() {
        //participants = new HashSet<Person>(0);
    }

    private Set participants = new HashSet(0);

    public Set getParticipants() {
        return participants;
    }

    public void setParticipants(Set participants) {
        this.participants = participants;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((date == null) ? 0 : date.hashCode());
        //result = prime * result + (int) (id ^ (id >>> 32));
        result = prime * result
                + ((location == null) ? 0 : location.hashCode());
        //result = prime * result + ((participants == null) ? 0 : participants.hashCode());
        result = prime * result + ((title == null) ? 0 : title.hashCode());
        return result;
    }

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

        if (location == null) {
            if (other.location != null)
                return false;
        } else if (!location.equals(other.location))
            return false;

        if (title == null) {
            if (other.title != null)
                return false;
        } else if (!title.equals(other.title))
            return false;
        return true;
    }

    @SuppressWarnings("unchecked")
    public void addToParticipants(Person person) {
        this.getParticipants().add(person);
        //person.addToEvent(this);
        person.getEvents().add(this);
    }

    public void removeFromParticipants(Person person) {
        this.getParticipants().remove(this);
        person.getEvents().remove(person);
    }

    public long getId() {
        return id;
    }

    private void setId(long id) {
        this.id = id;
    }

    public Date getDate() {
        return date;
    }

    public void setDate(Date date) {
        this.date = date;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getLocation() {
        return this.location;
    }

    public void setLocation(String location) {
        this.location = location;
    }
}

人.hbm.xml：

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC 
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="roseindia.tutorial.hibernate">
    <class name="Person" table="PERSON">
        <id name="id" column="PERSON_ID">
            <generator class="native" />
        </id>
        <property name="age" />
        <property name="firstname" />
        <property name="lastname" />

        <set name="events" table="PERSON_EVENT" inverse="false" lazy="true" cascade="all" >
            <key column="PERSON_ID" not-null="true" />
            <many-to-many column="EVENT_ID" class="Event" />
        </set>

        <set name="emailAddresses" table="PERSON_EMAIL_ADDR">
            <key column="PERSON_ID" />
            <element type="string" column="EMAIL_ADDR" />
        </set>
    </class>
</hibernate-mapping>

人.java

import java.util.HashSet;
import java.util.Set;

public class Person implements java.io.Serializable {
    private Set events = new HashSet<Event>();
    private Set emailAddresses = new HashSet();

    public Set getEmailAddresses() {
        return emailAddresses;
    }

    public void setEmailAddresses(Set emailAddresses) {
        this.emailAddresses = emailAddresses;
    }

    public void addToEvent(Event event) {
        this.getEvents().add(event);
        //event.addToParticipants(this);
        event.getParticipants().add(this);
    }

    public void removeFromEvent(Event event) {
        this.getEvents().remove(event);
        //event.removeFromParticipants(this);
        event.getParticipants().remove(this);
    }

    public Set getEvents() {
        return events;
    }

    public void setEvents(Set events) {
        this.events = events;
    }

    public Long getId() {
        return id;
    }

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

    public int getAge() {
        return age;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + age;
        result = prime * result
                + ((firstname == null) ? 0 : firstname.hashCode());
        result = prime * result
                + ((lastname == null) ? 0 : lastname.hashCode());
        return result;
    }

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

        if (firstname == null) {
            if (other.firstname != null)
                return false;
        } else if (!firstname.equals(other.firstname))
            return false;

        if (lastname == null) {
            if (other.lastname != null)
                return false;
        } else if (!lastname.equals(other.lastname))
            return false;
        return true;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getFirstname() {
        return firstname;
    }

    public void setFirstname(String firstname) {
        this.firstname = firstname;
    }

    public String getLastname() {
        return lastname;
    }

    public void setLastname(String lastname) {
        this.lastname = lastname;
    }

    private Long id;
    private int age;
    private String firstname;
    private String lastname;

    public Person() {
    }
}

ManyToManyExample.java

public class ManyToManyExample {

    /**
     * @param args
     */
    public static void main(String[] args) {
        Session session = null;
        try {
            SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
            session = sessionFactory.openSession();
            Transaction tx1 = session.beginTransaction();

            System.out.println("Loading Record");
            Event theEvent = (Event) session.get(Event.class, new Long(1));
            session.refresh(theEvent);
            Person person = new Person();
            person.setAge(31);
            person.getEvents().add(theEvent);
            person.setFirstname("RRRRRR");
            person.setLastname("NNNNNN");
            person.getEmailAddresses().add("RRRRRR@yahoo.com");

            theEvent.getParticipants().add(person); // Adding person ref. to event for many to many relation

            session.save(theEvent);
            session.save(person);
            tx1.commit(); 

            System.out.println("Done...");

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            session.flush();
            session.close();
        }
    }
}

运行上述示例时出现以下错误：INFO DefaultLoadEventListener:129 - Error execution load command org.hibernate.exception.GenericJDBCException: could not initialize a collection: [roseindia.tutorial.hibernate.Event.participants#1] at org.hibernate .exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:82) at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:70) at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43) at org. hibernate.loader.Loader.loadCollection(Loader.java:1351) at org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:101) at org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java: 484）在org.hibernate.event.def。DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60) at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1346) at org.hibernate.collection.AbstractPersistentCollection.forceInitialization(AbstractPersistentCollection.java:269) at org.hibernate.engine .PersistenceContext.initializeNonLazyCollections(PersistenceContext.java:745) 在 org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:208) 在 org.hibernate.loader.Loader.loadEntity(Loader.java:1255) 在 org.hibernate。 loader.entity.EntityLoader.load(EntityLoader.java:139) 在 org.hibernate.loader.entity.EntityLoader.load(EntityLoader.java:124) 在 org.hibernate.persister.entity.BasicEntityPersister.load(BasicEntityPersister.java: 2453）在org.hibernate.event.def。DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:387) at org.hibernate.event.def.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:368) at org.hibernate.event.def.DefaultLoadEventListener.load(DefaultLoadEventListener.java:166) at org .hibernate.event.def.DefaultLoadEventListener.load(DefaultLoadEventListener.java:140) 在 org.hibernate.event.def.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:249) 在 org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener .java:123) 在 org.hibernate.impl.SessionImpl.get(SessionImpl.java:561) 在 org.hibernate.impl.SessionImpl.get(SessionImpl.java:556) 在roseindia.tutorial.hibernate.ManyToManyExample.main( ManyToManyExample.java:24) 引起：java.sql.SQLException:[Microsoft][ODBC SQL Server 驱动程序]在 sun.jdbc.odbc.JdbcOdbc.standardError(JdbcOdbc.java:7113) 在 sun.jdbc.createSQLException(JdbcOdbc.java:6956) 在 sun.jdbc 的描述符索引无效.odbc.JdbcOdbc.SQLGetDataDouble(JdbcOdbc.java:3656) 在 sun.jdbc.odbc.JdbcOdbcResultSet.getDataDouble(JdbcOdbcResultSet.java:5574) 在 sun.jdbc.odbc.JdbcOdbcResultSet.getLong(JdbcOdbcResultSet.java:632) 在 sun. jdbc.odbc.JdbcOdbcResultSet.getLong(JdbcOdbcResultSet.java:650) at org.hibernate.type.LongType.get(LongType.java:26) at org.hibernate.type.NullableType.nullSafeGet(NullableType.java:77) at org .hibernate.type.NullableType.nullSafeGet(NullableType.java:68) 在 org.hibernate.persister.collection.AbstractCollectionPersister.readKey(AbstractCollectionPersister.java:612) 在 org.hibernate.loader.Loader。readCollectionElement(Loader.java:545) at org.hibernate.loader.Loader.readCollectionElements(Loader.java:344) at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:299) at org.hibernate.loader.Loader .doQuery(Loader.java:384) at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:203) at org.hibernate.loader.Loader.loadCollection(Loader.java:1344) ... 还有 20 个

我创建人员对象并通过使用 session.get(...) 获取事件来添加事件。对于多对多关系，在将每个对象添加到人员的事件列表之后，我正在做其他事情并将人员添加到事件对象的参与者列表中，这会引发异常。任何有帮助或指导都深表感谢！

我使用 SQL Server 2008 作为数据库。

4

1 回答 1

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尝试更改jdbc驱动包，可以使用jtds-1.2.jar，并将驱动类设置为net.sourceforge.jtds.jdbc.Driver

于 2012-08-07T12:55:10.333 回答