Hibernate 中的内部连接查询

Question

我想运行使用 Hibernate 进行查询，但我不知道我做错了什么导致出现错误。

我尝试关注

public List<String> findCourseForStudent(String pnr) {
       factory = new Configuration().configure().buildSessionFactory();
       Session session = factory.openSession();
       Transaction tx = null;

       try {
           tx = session.beginTransaction();
           String sql = "select Course.name from Course inner join CourseMaterial "
                + "on CourseMaterial.course_id = Course.id inner join CourseParticipantship "
                + "on CourseMaterial.id = CourseParticipantship.courseMaterial_id inner join Student "
                + "on Student.id=CourseParticipantship.student_id where Student.personalNumber='" + pnr + "'";
           SQLQuery query = session.createSQLQuery(sql);
           query.setResultTransformer(Criteria.ALIAS_TO_ENTITY_MAP);
           query.setParameter("pnr", pnr);
           List data = query.list();
           tx.commit();
           return data;
       } catch(HibernateException e) {
           if(tx != null) tx.rollback();
           e.printStackTrace();
       } finally {
           session.close();
       }
       return null;
}

但我收到以下错误：

net.sf.ehcache.CacheException: Another unnamed CacheManager already exists     in the same VM. Please provide unique names for each CacheManager in the config   or do one of following:
 1. Use one of the CacheManager.create() static factory methods to reuse same CacheManager with same name or create one if necessary
 2. Shutdown the earlier cacheManager before creating new one with same name.
 The source of the existing CacheManager is: DefaultConfigurationSource [ ehcache.xml or ehcache-failsafe.xml ]

我已经搜索了错误并尝试了一些解决方案，但其中 none 对我有用，所以我尝试使用 HQL 而不是直接使用 sql，但仍然没有成功：（我实际上不知道如何在 DetachedCriteria 中使用 INNER_JOIN 否则我认为使用 DetachedCriteria 我不会得到任何错误，因为我尝试将它用于更简单的查询并且它工作正常。

以下是一个简单查询的示例，它运行良好，但我不知道如何为 innerjoin 查询编写它

public List<Student> findForCourse(Integer integer) {
    DetachedCriteria criteria = DetachedCriteria.forClass(Student.class);
    criteria.add(Restrictions.eq("course.id", integer));
    criteria.add(Restrictions.ne("active", Boolean.FALSE));
    return getHibernateTemplate().findByCriteria(criteria);
}

Answer 1

终于，我找到了如何在休眠中编写查询

public List<String> findCourseForStudent(String pnr) {
    return jdbcTemplate.query(
            "select Course.name from Course inner join CourseMaterial "
                    + "on CourseMaterial.course_id = Course.id inner join CourseParticipantship "
                    + "on CourseMaterial.id = CourseParticipantship.courseMaterial_id inner join thd.dbo.Student "
                    + "on Student.id=CourseParticipantship.student_id where Student.personalNumber= ?", new Object[] { pnr }, new RowMapper() {
                public Object mapRow(ResultSet rs, int row) throws SQLException {
                    return rs;
                }

            });
}

Hibernate 中的内部连接查询

inner-join query in Hibernate

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