hibernate中的批量查詢 HQL查詢 Criteria查詢和原生SQL查詢

• HQL查詢----hibernate query language查詢-------適合用在簡單的多表查詢情況
• Criteria查詢------適合在單表查詢情況下使用
• 原生的SQL查詢-----復雜的業務查詢

    　　Hibernate獨家查詢語言

public class HqlDemo {
　　　　//查詢語句中本來應該是select * from Custmoer的完整類名,但是因為在工程只有一個Customer類，所以可不使用完整類名， select *可省略
    //寫死的hql查詢，注意CUST_NAME='Lisi'中存在的單引號，如果查詢的結果為多個結果，則使用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問號占位符查詢，因為hql語句中只有一個問號，所以其位置為0，所以在setParameter的時候第一個參數為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冒號占位符查詢
    @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分頁查詢
    @Test
    public void func4(){
        Session session= HibernateUtil.openSession();
        Transaction transaction=session.beginTransaction();
        String hql="from Customer ";
        Query query=session.createQuery(hql);
        query.setFirstResult(0);//從第幾條開始抓取
        query.setMaxResults(2);//抓幾條
        List<Customer> list=query.list();
        System.out.println(list);
        transaction.commit();
        HibernateUtil.closeSession(session);
    }
}

 

Criteria查詢，不用編寫sql語句，直接傳參即可

public class CriteriaDemo {
    //Criteria基本查詢,注意criteria()雖然接收的是字符串，但是類名不要加雙引號
    @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條件查詢
    @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分頁查詢
    @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統計總行數
    //可以使用Projections.max()  Projection.min()統計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條件查詢相關api

 

 

SQL語句原生查詢

    //SQL原生查詢中的基本查詢
    @Test
    public void func1(){
        Session session= HibernateUtil.openSession();
        Transaction transaction=session.beginTransaction();
        String sqlString="select * from CUST";
        SQLQuery sqlQuery=session.createSQLQuery(sqlString);
        //SQLQuery查詢將查詢到的每一行都封裝為一個Object[],因為有多行，所以返回的類型為List<Object[]>
        List<Object[]> list=sqlQuery.list();
        System.out.println(list);
        transaction.commit();
        HibernateUtil.closeSession(session);
    }

    //SQL原生查詢中的基本查詢
    @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);//通過此種方式使hibernate將返回的結果封裝為Customer類型
        List<Customer> list=sqlQuery.list();
        System.out.println(list);
        transaction.commit();
        HibernateUtil.closeSession(session);
    }

    //SQL原生查詢中的條件查詢
    @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原生查詢中的分頁查詢
    @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);
    }
}