博客

java的Hibernate框架报错“SessionException”的原因和解决方法

  • Post category:Java

当使用Java的Hibernate框架时，可能会遇到“SessionException”错误。这个错误通常是由以下原因之一引起的：

  • 会话关闭：如果会话已经关闭，则可能出现此错误。在这种情况下，需要确保会话没有关闭。

  • 事务已经提交或回滚：如果事务已经提交或回滚，则可能会出现此错误。在这种情况下，需要确保事务没有提交或回滚。

以下是两个实例：

例 1

如果会话已经关闭，则可以尝试确保会话没有关闭。例如，如果您尝试使用以下代码时出现“SessionException”错误：

SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
Session session = sessionFactory.openSession();
Transaction transaction = session.beginTransaction();
User user = new User();
user.setName("John");
session.save(user);
transaction.commit();
session.close();

// In another transaction or session
Session session2 = sessionFactory.openSession();
Transaction transaction2 = session2.beginTransaction();
User user2 = session2.get(User.class, 1L);
session2.save(user2);
transaction2.commit();
session2.close();

// In another transaction or session
Session session3 = sessionFactory.openSession();
Transaction transaction3 = session3.beginTransaction();
User user3 = session3.get(User.class, 1L);
session3.delete(user3);
transaction3.commit();
session3.close();

// In another transaction or session
Session session4 = sessionFactory.openSession();
Transaction transaction4 = session4.beginTransaction();
User user4 = session4.get(User.class, 1L);
user4.setName("Jane");
session4.update(user4);
transaction4.commit();
session4.close();

但是，如果会话已经关闭，则可以尝试在每个事务或会话中使用try-with-resources语句来确保会话没有关闭。例如，您可以使用以下代码：

SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
try (Session session = sessionFactory.openSession()) {
    try (Transaction transaction = session.beginTransaction()) {
        User user = new User();
        user.setName("John");
        session.save(user);
        transaction.commit();
    }

    try (Session session2 = sessionFactory.openSession()) {
        try (Transaction transaction2 = session2.beginTransaction()) {
            User user2 = session2.get(User.class, 1L);
            session2.save(user2);
            transaction2.commit();
        }
    }

    try (Session session3 = sessionFactory.openSession()) {
        try (Transaction transaction3 = session3.beginTransaction()) {
            User user3 = session3.get(User.class, 1L);
            session3.delete(user3);
            transaction3.commit();
        }
    }

    try (Session session4 = sessionFactory.openSession()) {
        try (Transaction transaction4 = session4.beginTransaction()) {
            User user4 = session4.get(User.class, 1L);
            user4.setName("Jane");
            session4.update(user4);
            transaction4.commit();
        }
    }
}

在这个例子中，我们使用try-with-resources语句来确保会话没有关闭。

实例 2

如果事务已经提交或回滚，则可以尝试确保事务没有提交或回滚。例如，如果您尝试使用以下代码时出现“SessionException”错误：

SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
Session session = sessionFactory.openSession();
Transaction transaction = session.beginTransaction();
User user = new User();
user.setName("John");
session.save(user);
transaction.commit();
session.close();

// In another transaction or session
Session session2 = sessionFactory.openSession();
Transaction transaction2 = session2.beginTransaction();
User user2 = session2.get(User.class, 1L);
session2.save(user2);
transaction2.commit();
session2.close();

// In another transaction or session
Session session3 = sessionFactory.openSession();
Transaction transaction3 = session3.beginTransaction();
User user3 = session3.get(User.class, 1L);
session3.delete(user3);
transaction3.commit();
session3.close();

// In another transaction or session
Session session4 = sessionFactory.openSession();
Transaction transaction4 = session4.beginTransaction();
User user4 = session4.get(User.class, 1L);
user4.setName("Jane");
session4.update(user4);
transaction4.commit();
session4.close();

但是，如果事务已经提交或回滚，则可以尝试在每个事务或会话中使用try-catch语句来确保事务没有提交或回滚。例如，您可以使用以下代码：

SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
try (Session session = sessionFactory.openSession()) {
    try (Transaction transaction = session.beginTransaction()) {
        User user = new User();
        user.setName("John");
        session.save(user);
        transaction.commit();
    } catch (Exception e) {
        e.printStackTrace();
    }

    try (Session session2 = sessionFactory.openSession()) {
        try (Transaction transaction2 = session2.beginTransaction()) {
            User user2 = session2.get(User.class, 1L);
            session2.save(user2);
            transaction2.commit();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    try (Session session3 = sessionFactory.openSession()) {
        try (Transaction transaction3 = session3.beginTransaction()) {
            User user3 = session3.get(User.class, 1L);
            session3.delete(user3);
            transaction3.commit();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    try (Session session4 = sessionFactory.openSession()) {
        try (Transaction transaction4 = session4.beginTransaction()) {
            User user4 = session4.get(User.class, 1L);
            user4.setName("Jane");
            session4.update(user4);
            transaction4.commit();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

在这个例子中，我们使用try-catch语句来确保事务没有提交或回滚。

总之，要解决“SessionException”错误，您需要确保会话没有关闭，或者确保事务没有提交或回滚。如果问题仍然存在，请查看Hibernate文档或寻求其他帮助。

Tags: ,