Hibernate常用查询

public class testDemo {
    @Test
    public void test15() {
        Session session = HibernateUtil.openSession();
        Transaction tx = session.beginTransaction();
        //内连接
/*        Query query = session.createQuery("from Student s inner join s.orders");
        List<Object[]> list = query.list();
        for (Object[] objects : list) {
            System.out.println(Arrays.toString(objects));
        }*/
        //迫切内连接
        Query query = session.createQuery("select distinct s from Student s inner join fetch s.orders");
        List list = query.list();
        System.out.println(list);
        tx.commit();
        session.close();
    }
    
    /**
     * 模糊查询
     */
    @Test
    public void test14() {
        Session session = HibernateUtil.openSession();
        Transaction tx = session.beginTransaction();
        //HQL模糊查询
/*        Query query = session.createQuery("from Student where sname like ?");
        query.setParameter(0, "赵%");
        List<Student> list = query.list();
        System.out.println(list);*/

        //QBC模糊查询
        Criteria criteria = session.createCriteria(Student.class);
        criteria.add(Restrictions.like("sname", "赵%"));
        List<Student> list = criteria.list();
        System.out.println(list);
        tx.commit();
        session.close();
    }
    
    /**
     * 投影操作:查询对象的某几个属性
     * 
     *
     */
    @Test
    public void test13() {
        Session session = HibernateUtil.openSession();
        Transaction tx = session.beginTransaction();
        //查询多个就要加[]了必须用循环 输出
    /*    List<Object[]> list = session.createQuery("select s.sname,s.stuid from Student s").list();
        for (Object[] objects : list) {
            System.out.println(Arrays.toString(objects));
        }
        */
        //必须有构造函数只查sname就必须添加一个只有name的构造函数
        List<Student> list = session.createQuery("select new Student(sname) from Student").list();
        System.out.println(list);
        tx.commit();
        session.close();

    }
    
    @Test
    public void test12() {
        Session session = HibernateUtil.openSession();
        Transaction tx = session.beginTransaction();
        //查询用户名字  List<>泛型中不管有什么都可以用Object  Object超级父类
        List<Object> list = session.createQuery("select s.sname from Student s").list();
        System.out.println(list);
        tx.commit();
        session.close();

    }
    
    @Test
    public void test11() {
        Session session = HibernateUtil.openSession();
        Transaction tx = session.beginTransaction();
        Query query = session.createQuery("from Student where sname=:name and stuid=:id");
        //这里的name对应着HQL语句:后的name
        query.setString("name", "赵云");
        query.setInteger("id", 4);
        List<Student> list = query.list();
        System.out.println(list);
        tx.commit();
        session.close();

    }
    
    @Test
    public void test10() {
        Session session = HibernateUtil.openSession();
        Transaction tx = session.beginTransaction();
        Query query = session.createQuery("from Student where sname=? and stuid=?");
        query.setString(0, "赵云");
        query.setInteger(1, 4);
        List<Student> list = query.list();
        System.out.println(list);
        tx.commit();
        session.close();

    }
    
    
    @Test
    public void test9() {
        //QBC检索一条数据  .uniqueResult()是只查一条语句如果数据库查出了多条语句会报错
        Session session = HibernateUtil.openSession();
        Transaction tx = session.beginTransaction();
        Student student = (Student) session.createCriteria(Student.class)
        .add(Restrictions.eq("sname", "皇子")).uniqueResult();
        System.out.println(student);
        tx.commit();
        session.close();

    }
    
    @Test
    public void test8() {
        //HQL检索一条数据 .uniqueResult()是只查一条语句如果数据库查出了多条语句会报错
        Session session = HibernateUtil.openSession();
        Transaction tx = session.beginTransaction();
        Student student = (Student) session.createQuery("from Student where sname=?")
                        .setString(0, "赵云").uniqueResult();
        System.out.println(student);
        tx.commit();
        session.close();

    }
    
    @Test
    public void test7() {
        //用QBC实现分页
        Session session = HibernateUtil.openSession();
        Transaction tx = session.beginTransaction();

        Criteria criteria = session.createCriteria(Orders.class);
        //setFirstResult()设置参数表示下标 从0开始 表示第一个数据  从第几条数据开始
        criteria.setFirstResult(0);
        //setMaxResults()设置每页显示的数量
        criteria.setMaxResults(10);
        List<Orders> list = criteria.list();
        for (Orders orders : list) {
            System.out.println(orders);
        }
        
        tx.commit();
        session.close();

    }
    
    @Test
    public void test6() {
        //用HQL实现分页
        Session session = HibernateUtil.openSession();
        Transaction tx = session.beginTransaction();

        Query query = session.createQuery("from Orders");
        //setFirstResult()设置参数表示下标 从0开始 表示第一个数据  从第几条数据开始
        query.setFirstResult(0);
        //setMaxResults()设置每页显示的数量
        query.setMaxResults(10);
        List<Orders> list = query.list();
        for (Orders orders : list) {
            System.out.println(orders);
        }
        
        tx.commit();
        session.close();

    }
    

    @Test
    public void test5() {

        Session session = HibernateUtil.openSession();
        Transaction tx = session.beginTransaction();

/*        List<Student> list = session.createQuery("from Student s order by s.stuid desc").list();
        for (Student student : list) {
            System.out.println(student);
        }*/
        //使用QBC进行排序
        List<Student> list = session.createCriteria(Student.class)
        .addOrder(org.hibernate.criterion.Order.desc("stuid"))
        .list();
        for (Student student : list) {
            System.out.println(student);
        }
        tx.commit();
        session.close();

    }
    /**
     * 排序 使用HQL操作
     *         默认升序ASC   降序desc
     *         使用QBC进行排序  固定写法
     *         .addOrder(org.hibernate.criterion.Order.desc("stuid"))
     *         .desc("字段")根据这个字段排序
     *         .asc()正序
     */
    

    @Test
    public void test4() {

        Session session = HibernateUtil.openSession();
        Transaction tx = session.beginTransaction();

        
        tx.commit();
        session.close();

    }
    /**
     * 多态检索
     * 因为session.createQuery("from java.lang.Object").list();查询的是object对象
     *     <mapping resource="com/bdqn/pojo/Orders.hbm.xml" />
     *    <mapping resource="com/bdqn/pojo/Student.hbm.xml" />     
     * 会返回所有对象
     */
    @Test
    public void test3() {

        Session session = HibernateUtil.openSession();
        Transaction tx = session.beginTransaction();
        List<Object> list = session.createQuery("from java.lang.Object").list();
        for (Object object : list) {
            System.out.println(object);
        }
        tx.commit();
        session.close();

    }
    
    @Test
    public void test2(){
        
        Session session = HibernateUtil.openSession();
        Transaction tx = session.beginTransaction();
        //使用别名查询
/*        List<Student> list = session.createQuery("from Student s").list();
        System.out.println(list);*/
        //使用别名带参数查询
        List<Student> list = session.createQuery("from Student s where s.sname=?").setString(0, "赵云").list();
        System.out.println(list);
        tx.commit();
        session.close();
    }

    @Test
    public void test1(){
        
        Session session = HibernateUtil.openSession();
        Transaction tx = session.beginTransaction();
        //使用HQL查询
/*        List<Student> list = session.createQuery("from Student").list();
        for (Student student : list) {
            System.out.println(student);
        }*/
        //使用QBC查询
/*        List<Student> list = session.createCriteria(Student.class).list();
        for (Student student : list) {
            System.out.println(student);
        }*/
        //使用sql查询
        List<Student> list = session.createSQLQuery("select * from Student").addEntity(Student.class).list();
        for (Student student : list) {
            System.out.println(student);
        }
        tx.commit();
        session.close();
        
        
        
    }
    
    
    
}