java Hibernate：“会话已关闭”，但从未关闭（手动）

7 月 Questions & Answers 6426

我遇到了一个非常奇怪的问题，我完全无法理解为什么会发生这种情况

问题是这样的：

我得到了一个名为“SmampiAccount”的类，其中包含一个电子邮件帐户列表。映射文件如下所示（缩短）：

<hibernate-mapping>
    <class name="com.smampi.web.model.account.SmampiAccount" table="SMAMPIACCOUNT">
            <id name="id" type="long" access="field">
                    <column name="SMAMPI_ACCOUNT_ID" />
                    <generator class="native" />
            </id>

            <bag name="mailAccounts" table="MAILACCOUNTS" lazy="false" inverse="true">
                    <key column="SMAMPI_ACCOUNT_ID"></key>
                    <one-to-many class="com.smampi.web.model.mail.account.MailAccount"/>
            </bag>
    </class>
</hibernate-mapping>

我通过以下方法获取此类的实例：

public SmampiAccount loadSmampiAccount(long id) throws FailedDatabaseOperationException {

    SmampiAccount smampiAccount = null;
    Session session = null;
    Transaction transaction = null;
    try {
        session = getSession();
        transaction = session.beginTransaction();
        smampiAccount = (SmampiAccount) session.load(com.smampi.web.model.account.SmampiAccount.class, id);
        List<MailAccount> mailAccounts = smampiAccount.getMailAccounts();
        doSomething(mailAccounts);
        transaction.commit();
    } catch (Exception e) {
        rollback(transaction);
        closeSession();
        throw new FailedDatabaseOperationException(e);
    } finally {
        closeSession();
    }

    return smampiAccount;
}

private Session getSession() {
    if (_session == null) {
        _session = getSessionFactory().openSession();
    }
    if (_session.isOpen() == false) {
        _session = getSessionFactory().openSession();
    }
    return _session;
}

这样做很好

现在，我想向映射文件添加一个新属性，以便保存对默认电子邮件帐户的引用：

<many-to-one name="defaultMailAccount" column="DEFAULT_MAIL_ACCOUNT_ID" />

现在，我在这一行的方法public smipaccount loadsmipaccount（long id）中得到一个异常：

List<MailAccount> mailAccounts = smampiAccount.getMailAccounts();

Stacktrace:

org.hibernate.SessionException: Session is closed!
    at org.hibernate.impl.AbstractSessionImpl.errorIfClosed(AbstractSessionImpl.java:72)
    at org.hibernate.impl.SessionImpl.getPersistenceContext(SessionImpl.java:1954)
    at org.hibernate.event.def.DefaultPostLoadEventListener.onPostLoad(DefaultPostLoadEventListener.java:49)
    at org.hibernate.engine.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:250)
    at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:982)
    at org.hibernate.loader.Loader.doQuery(Loader.java:857)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:274)
    at org.hibernate.loader.Loader.loadEntity(Loader.java:2037)
    at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:86)
    at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:76)
    at org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:3293)
    at org.hibernate.event.def.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:496)
    at org.hibernate.event.def.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:477)
    at org.hibernate.event.def.DefaultLoadEventListener.load(DefaultLoadEventListener.java:227)
    at org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:147)
    at org.hibernate.impl.SessionImpl.fireLoad(SessionImpl.java:1090)
    at org.hibernate.impl.SessionImpl.immediateLoad(SessionImpl.java:1026)
    at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:176)
    at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:215)
    at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:190)
    at com.smampi.web.model.account.SmampiAccount_$$_javassist_19.getMailAccounts(SmampiAccount_$$_javassist_19.java)

这怎么可能？该会话没有手动关闭，并且还没有调用.commit()（这通常会关闭该会话）。这里也不可能有其他方法干扰，因为我为每个方法调用创建了一个新的hibernate会话，该会话专门用于这一个方法

编辑

我添加了一些有关会话打开状态的调试信息：

session = getSession();

System.err.println(session.isOpen());
transaction = session.beginTransaction(); // 1 (true)

System.err.println(session.isOpen()); // 2 (true)
smampiAccount = (SmampiAccount) session.load(com.smampi.web.model.account.SmampiAccount.class, id);

System.err.println(session.isOpen()); // 3 (true)
List<MailAccount> mailAccounts = smampiAccount.getMailAccounts(); // Throws exception that session is closed
doSomething(mailAccounts);

System.err.println(session.isOpen()); // 4 (not called)
transaction.commit();

这给了我：

true
true
true
org.hibernate.SessionException: Session is closed!

共 (1) 个答案

# 1 楼答案
我是世界上最大的白痴

在defaultMailAccount的setter中，我有：
```
public void setDefaultMailAccount(MailAccount defaultMailAccount) {
    this.defaultMailAccount = defaultMailAccount;
    try {
        databasecontroller.update(this);
    } catch (FailedDatabaseOperationException e) {
        handleException(e, false, null, null);
    }
}
```
每当Hibernate试图从数据库加载持久化版本时，对databasecontroller.update(this)的调用就会导致级联，这再次导致会话关闭

将databasecontroller.update(..)的调用移到方法外部修复了这个问题

很抱歉占用了大家的时间，谢谢大家的帮助

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java Hibernate：“会话已关闭”，但从未关闭（手动）

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# 1 楼答案