hibernate中的批量查询 HQL查询 Criteria查询和原生SQL查询

• HQL查询----hibernate query language查询-------适合用在简单的多表查询情况
• Criteria查询------适合在单表查询情况下使用
• 原生的SQL查询-----复杂的业务查询

    　　Hibernate独家查询语言

public class HqlDemo {
　　　　//查询语句中本来应该是select * from Custmoer的完整类名,但是因为在工程只有一个Customer类，所以可不使用完整类名， select *可省略
    //写死的hql查询，注意CUST_NAME='Lisi'中存在的单引号，如果查询的结果为多个结果，则使用query.createUniqueResult()
    @Test
    public void func1(){
        Session session= HibernateUtil.openSession();
        Transaction transaction=session.beginTransaction();
        String hql="from Customer where CUST_NAME='Lisi'";
        Query query=session.createQuery(hql);
        List<Customer> list=query.list();
        System.out.println(list);
        transaction.commit();
        HibernateUtil.closeSession(session);
    }




    //hql问号占位符查询，因为hql语句中只有一个问号，所以其位置为0，所以在setParameter的时候第一个参数为0
    @Test
    public void func2(){
        Session session= HibernateUtil.openSession();
        Transaction transaction=session.beginTransaction();
        String hql="from Customer where CUST_NAME= ?";
        Query query=session.createQuery(hql);
        query.setParameter(0, "Lisi");
        List<Customer> list=query.list();
        System.out.println(list);
        transaction.commit();
        HibernateUtil.closeSession(session);
    }



    //hql冒号占位符查询
    @Test
    public void func3(){
        Session session= HibernateUtil.openSession();
        Transaction transaction=session.beginTransaction();
        String hql="from Customer where CUST_NAME= :cust_name";
        Query query=session.createQuery(hql);
        query.setParameter("cust_name","Lisi");
        List<Customer> list=query.list();
        System.out.println(list);
        transaction.commit();
        HibernateUtil.closeSession(session);
    }


    //hibernate分页查询
    @Test
    public void func4(){
        Session session= HibernateUtil.openSession();
        Transaction transaction=session.beginTransaction();
        String hql="from Customer ";
        Query query=session.createQuery(hql);
        query.setFirstResult(0);//从第几条开始抓取
        query.setMaxResults(2);//抓几条
        List<Customer> list=query.list();
        System.out.println(list);
        transaction.commit();
        HibernateUtil.closeSession(session);
    }
}

 

Criteria查询，不用编写sql语句，直接传参即可

public class CriteriaDemo {
    //Criteria基本查询,注意criteria()虽然接收的是字符串，但是类名不要加双引号
    @Test
    public void func1(){
        Session session= HibernateUtil.openSession();
        Transaction transaction=session.beginTransaction();
        Criteria criteria=session.createCriteria(Customer.class);
        List<Customer> list=criteria.list();
        System.out.println(list);
        transaction.commit();
        HibernateUtil.closeSession(session);
    }


    //Criteria条件查询
    @Test
    public void func2(){
        Session session= HibernateUtil.openSession();
        Transaction transaction=session.beginTransaction();
        Criteria criteria=session.createCriteria(Customer.class);
        criteria.add(Restrictions.eq("cust_name","Lisi"));
        criteria.add(Restrictions.or(Restrictions.gt("cust_level",2),Restrictions.lt("cust_level","4")));
        List<Customer> list=criteria.list();
        System.out.println(list);
        transaction.commit();
        HibernateUtil.closeSession(session);
    }


    //Criteria分页查询
    @Test
    public void func3(){
        Session session= HibernateUtil.openSession();
        Transaction transaction=session.beginTransaction();
        Criteria criteria=session.createCriteria(Customer.class);
        criteria.setFirstResult(1);
        criteria.setMaxResults(2);
        List<Customer> list=criteria.list();
        System.out.println(list);
        transaction.commit();
        HibernateUtil.closeSession(session);
    }

    //Criteria统计总行数
    //可以使用Projections.max()  Projection.min()统计某一列的最大值最小值
    @Test
    public void func4(){
        Session session= HibernateUtil.openSession();
        Transaction transaction=session.beginTransaction();
        Criteria criteria=session.createCriteria(Customer.class);
        criteria.setProjection(Projections.rowCount());
        Long count=(Long)criteria.uniqueResult();
        System.out.println(count);
        transaction.commit();
        HibernateUtil.closeSession(session);
    }
}

 criteria条件查询相关api

 

 

SQL语句原生查询

    //SQL原生查询中的基本查询
    @Test
    public void func1(){
        Session session= HibernateUtil.openSession();
        Transaction transaction=session.beginTransaction();
        String sqlString="select * from CUST";
        SQLQuery sqlQuery=session.createSQLQuery(sqlString);
        //SQLQuery查询将查询到的每一行都封装为一个Object[],因为有多行，所以返回的类型为List<Object[]>
        List<Object[]> list=sqlQuery.list();
        System.out.println(list);
        transaction.commit();
        HibernateUtil.closeSession(session);
    }

    //SQL原生查询中的基本查询
    @Test
    public void func2(){
        Session session= HibernateUtil.openSession();
        Transaction transaction=session.beginTransaction();
        String sqlString="select * from CUST";
        SQLQuery sqlQuery=session.createSQLQuery(sqlString);
        sqlQuery.addEntity(Customer.class);//通过此种方式使hibernate将返回的结果封装为Customer类型
        List<Customer> list=sqlQuery.list();
        System.out.println(list);
        transaction.commit();
        HibernateUtil.closeSession(session);
    }

    //SQL原生查询中的条件查询
    @Test
    public void func3(){
        Session session= HibernateUtil.openSession();
        Transaction transaction=session.beginTransaction();
        String sqlString="select * from CUST where cust_name=?";
        SQLQuery sqlQuery=session.createSQLQuery(sqlString);
        sqlQuery.addEntity(Customer.class);
        sqlQuery.setParameter(0,"Lisi");
        List<Customer> list=sqlQuery.list();
        System.out.println(list);
        transaction.commit();
        HibernateUtil.closeSession(session);
    }

    //SQL原生查询中的分页查询
    @Test
    public void func4(){
        Session session= HibernateUtil.openSession();
        Transaction transaction=session.beginTransaction();
        String sqlString="select * from CUST";
        SQLQuery sqlQuery=session.createSQLQuery(sqlString);
        sqlQuery.addEntity(Customer.class);
        sqlQuery.setFirstResult(1);
        sqlQuery.setMaxResults(2);
        List<Customer> list=sqlQuery.list();
        System.out.println(list);
        transaction.commit();
        HibernateUtil.closeSession(session);
    }
}