Hibernate的批量查询

Hibernate的查询大致分为以下三种场景，

　　1.　　HQL查询-hibernate Query Language(多表查询,但不复杂时使用)

　 2.　　Criteria查询(单表条件查询)

　　3.　　原生SQL查询(复杂的业务查询)

接下来解释三种使用方法:

1.HQL查询-hibernate Query Language(多表查询,但不复杂时使用)　　Hibernate独家查询语言,属于面向对象的查询语言，HQL语言中不会出现SQL中的表和列，HQL使用的都是JavaBean的类名和属性名。

1.HQL基本查询

(1)查询所有的基本语句

    @Test// HQL查询所有数据public void fun1() {// 1 获得sessionSession session = HibernateUtil.openSession();// 2.书写HQL语句String hql = "from cn.qlq.domain.Customer";// from 类名全路径// 3.根据hql创建查询对象Query query = session.createQuery(hql);// 4.根据查询对象获取查询结果List<Customer> customers = query.list();System.out.println(customers);}

结果:

Hibernate: selectcustomer0_.cust_id as cust_id1_0_,customer0_.cust_name as cust_nam2_0_,customer0_.cust_source as cust_sou3_0_,customer0_.cust_industry as cust_ind4_0_,customer0_.cust_level as cust_lev5_0_,customer0_.cust_linkman as cust_lin6_0_,customer0_.cust_phone as cust_pho7_0_,customer0_.cust_mobile as cust_mob8_0_ fromcst_customer customer0_
[Customer [cust_id=1, cust_name=XXXXXXXXXX], Customer [cust_id=2, cust_name=联想]]

改进:如果整个项目中只有一个类的名字可以省略包路径，也就是可以只写类名:

    @Test// HQL查询所有数据public void fun1() {// 1 获得sessionSession session = HibernateUtil.openSession();// 2.书写HQL语句
//        String hql = "from cn.qlq.domain.Customer";// from 类名全路径String hql = "from Customer";// 如果整个项目中只有这一个类名可以直接写名字// 3.根据hql创建查询对象Query query = session.createQuery(hql);// 4.根据查询对象获取查询结果List<Customer> customers = query.list();System.out.println(customers);}

(2)根据主键查询单个

    @Test// HQL查询单个数据public void fun2() {// 1 获得sessionSession session = HibernateUtil.openSession();// 2.书写HQL语句
//        String hql = "from cn.qlq.domain.Customer";// from 类名全路径String hql = "from Customer where cust_id = 1";// where后面是Customer的属性名称而不是列名// 3.根据hql创建查询对象Query query = session.createQuery(hql);// 4.根据查询对象获取查询结果Customer customer = (Customer) query.uniqueResult();System.out.println(customer);}

2.HQL条件查询:

(1)?占位符查询

　　类似于JDBC的占位符，只是hibernate的?下标从0开始，而JDBC的下标从1开始，基本上所有的编程索引都从0开始，唯独JDBC从1开始。。。。

    @Test// HQL的?占位符查询public void fun3() {// 1 获得sessionSession session = HibernateUtil.openSession();// 2.书写HQL语句
//        String hql = "from cn.qlq.domain.Customer";// from 类名全路径String hql = "from Customer where cust_id = ?";// 如果整个项目中只有这一个类名可以直接写名字// 3.根据hql创建查询对象Query query = session.createQuery(hql);
//        query.setLong(0, 1l);//类似于JDBC的占位符，只是JDBC的占位符下标从0开始，hibernate从1开始query.setParameter(0, 1l);//这种写法不用管类型// 4.根据查询对象获取查询结果Customer customer = (Customer) query.uniqueResult();System.out.println(customer);}

(2)命令占位符：name格式的查询，固定格式，name随便起，习惯性的起做和条件名字一样

    @Test// HQL的命令占位符查询public void fun4() {// 1 获得sessionSession session = HibernateUtil.openSession();// 2.书写HQL语句
//        String hql = "from cn.qlq.domain.Customer";// from 类名全路径String hql = "from Customer where cust_id = :cust_id";// :cust_id的名字随便起，只不过习惯性的起做一样// 3.根据hql创建查询对象Query query = session.createQuery(hql);
//        query.setLong(0, 1l);//类似于JDBC的占位符，只是JDBC的占位符下标从0开始，hibernate从1开始query.setParameter("cust_id",1l);// 4.根据查询对象获取查询结果Customer customer = (Customer) query.uniqueResult();System.out.println(customer);}

3.HQL排序与分页查询

　　分页查询类似于mysql的limit关键字，limit start，pageSize。。。。。。

    @Test// HQL分页查询public void fun5() {// 1 获得sessionSession session = HibernateUtils.openSession();// 2.书写HQL语句
//        String hql = "from cn.qlq.domain.Customer";// from 类名全路径String hql = "from Customer order by cust_id desc";// :cust_id的名字随便起，只不过习惯性的起做一样// 3.根据hql创建查询对象Query query = session.createQuery(hql);/*** 类似于 limit start,pageSize;* 假设页大小是2* 页号 起始值  页大小* 1   0    2* 2   2    2*///例如取第二页数据query.setFirstResult(2);query.setMaxResults(2);// 4.根据查询对象获取查询结果List<Customer> customers = query.list();System.out.println(customers);}

结果:

Hibernate: selectcustomer0_.cust_id as cust_id1_0_,customer0_.cust_name as cust_nam2_0_,customer0_.cust_source as cust_sou3_0_,customer0_.cust_industry as cust_ind4_0_,customer0_.cust_level as cust_lev5_0_,customer0_.cust_linkman as cust_lin6_0_,customer0_.cust_phone as cust_pho7_0_,customer0_.cust_mobile as cust_mob8_0_ fromcst_customer customer0_ limit ?,?

[Customer [cust_id=2, cust_name=新增数据], Customer [cust_id=1, cust_name=程序员111]]

2.Criteria查询(单表条件查询)

　　criteria查询相比于上面的HQL查询要简单的多。

1.基本查询---查询所有

    @Test// 查询所有public void test1() {// 1 获得sessionSession session = HibernateUtils.openSession();// 2.創建criteria进行查询Criteria criteria = session.createCriteria(Customer.class);List<Customer> list = criteria.list();System.out.println(list);}

结果:

[Customer [cust_id=1, cust_name=程序员111], Customer [cust_id=2, cust_name=新增数据], Customer [cust_id=3, cust_name=测试名称222], Customer [cust_id=4, cust_name=测试名称222]]

2. 条件查询单个:

    @Test// 根据ID查询单个,条件查询public void test2() {// 1 获得sessionSession session = HibernateUtils.openSession();// 2.創建criteria进行查询Criteria criteria = session.createCriteria(Customer.class);criteria.add(Restrictions.eq("cust_id", 1l));Customer customer = (Customer) criteria.uniqueResult();System.out.println(customer);}

结果:

Customer [cust_id=1, cust_name=程序员111]

条件列表:

3.分页查询:

    @Test// 分页查询public void test3() {// 1 获得sessionSession session = HibernateUtils.openSession();// 2.創建criteria进行查询Criteria criteria = session.createCriteria(Customer.class);/*** 类似于 limit start,pageSize;* 假设页大小是2* 页号 起始值  页大小* 1   0    2* 2   2    2*/criteria.setFirstResult(2);criteria.setMaxResults(2);List<Customer> list = criteria.list();System.out.println(list);}

结果:

[Customer [cust_id=3, cust_name=测试名称222], Customer [cust_id=4, cust_name=测试名称222]]

4.排序分组使用

    @Test// 排序和分组public void test5() {// 1 获得sessionSession session = HibernateUtils.openSession();// 2.排序Criteria criteria = session.createCriteria(Customer.class);criteria.addOrder(Order.desc("cust_id"));List<Customer> list = criteria.list();System.out.println(list);System.out.println();// 2.分组Criteria criteria1 = session.createCriteria(Customer.class);criteria1.setProjection(Projections.groupProperty("cust_name"));List<Customer> list1 = criteria1.list();System.out.println(list1);}

结果：

[Customer [cust_id=4, cust_name=测试名称222], Customer [cust_id=3, cust_name=测试名称222], Customer [cust_id=2, cust_name=新增数据], Customer [cust_id=1, cust_name=程序员111]]

[新增数据, 测试名称222, 程序员111]

5.聚集函数查询总数

    @Test// 查询总数（聚集函数的使用）public void test4() {// 1 获得sessionSession session = HibernateUtils.openSession();// 2.聚集函数查询总数Criteria criteria = session.createCriteria(Customer.class);criteria.setProjection(Projections.rowCount());Long count = (Long) criteria.uniqueResult();System.out.println(count);// 3.聚集函数查询总数第二种方法Criteria criteria1 = session.createCriteria(Customer.class);criteria1.setProjection(Projections.count("cust_id"));Long count1 = (Long) criteria.uniqueResult();System.out.println(count1);// 4.聚集函数查询几个不同的姓名Criteria criteria2 = session.createCriteria(Customer.class);criteria2.setProjection(Projections.countDistinct("cust_name"));Long count2 = (Long) criteria2.uniqueResult();System.out.println(count2);}

结果:

4
4
3

3.Hibernate种的原生SQL查询(用于处理一些复杂的业务逻辑)

1.基本查询

1.查询结构是数组集合

    @Test// 基本查询--返回数组listpublic void test1() {// 1.获取与线程绑定的sessionSession session = HibernateUtils.getCurrentSession();// 2.开启事务Transaction tx = session.beginTransaction();String sql = "select * from cst_customer";// 3.构造Query对象进行查询SQLQuery sqlQuery = session.createSQLQuery(sql);List<Object[]> list = sqlQuery.list();for (Object[] o : list) {System.out.println(Arrays.toString(o));}// 提交事务
        tx.commit();}

结果

[1, 程序员111, null, null, null, null, null, null]
[2, 新增数据, null, null, null, null, null, null]
[3, 测试名称222, null, null, null, null, null, null]
[4, 测试名称222, null, null, null, null, null, null]

2.查询结果是对象集合(重要)

    @Test// 基本查询--返回对象listpublic void test2() {// 1.获取与线程绑定的sessionSession session = HibernateUtils.getCurrentSession();// 2.开启事务Transaction tx = session.beginTransaction();String sql = "select * from cst_customer";// 3.构造Query对象进行查询SQLQuery sqlQuery = session.createSQLQuery(sql);sqlQuery.addEntity(Customer.class);List<Customer> list = sqlQuery.list();System.out.println(list);// 提交事务
        tx.commit();}

结果

[Customer [cust_id=1, cust_name=程序员111], Customer [cust_id=2, cust_name=新增数据], Customer [cust_id=3, cust_name=测试名称222], Customer [cust_id=4, cust_name=测试名称222]]

2.条件查询

    @Test// 基本查询--返回对象listpublic void test3() {// 1.获取与线程绑定的sessionSession session = HibernateUtils.getCurrentSession();// 2.开启事务Transaction tx = session.beginTransaction();String sql = "select * from cst_customer where cust_id=?";// 3.构造Query对象进行查询SQLQuery sqlQuery = session.createSQLQuery(sql);sqlQuery.addEntity(Customer.class);sqlQuery.setParameter(0, 1l);Customer cus = (Customer) sqlQuery.uniqueResult();System.out.println(cus);// 提交事务
        tx.commit();}

结果

Customer [cust_id=1, cust_name=程序员111]

3.聚集函数查询总数

    @Test// 基本查询--查询总数public void test4() {// 1.获取与线程绑定的sessionSession session = HibernateUtils.getCurrentSession();// 2.开启事务Transaction tx = session.beginTransaction();String sql = "select count(*) from cst_customer";// 3.构造Query对象进行查询SQLQuery sqlQuery = session.createSQLQuery(sql);BigInteger bg = (BigInteger) sqlQuery.uniqueResult();System.out.println(bg);// 提交事务
        tx.commit();}

结果

4.排序与分页综合查询

    @Test// 基本查询--分页查询public void test5() {// 1.获取与线程绑定的sessionSession session = HibernateUtils.getCurrentSession();// 2.开启事务Transaction tx = session.beginTransaction();//按cust_id降序排序String sql = "select *  from cst_customer order by cust_id desc limit ?,?";// 3.构造Query对象进行查询SQLQuery sqlQuery = session.createSQLQuery(sql);sqlQuery.addEntity(Customer.class);/*** 分页查询  取第二页，页大小是二*/sqlQuery.setParameter(0, 2);sqlQuery.setParameter(1, 2);List<Customer> list = sqlQuery.list();System.out.println(list);// 提交事务
        tx.commit();}

结果

[Customer [cust_id=2, cust_name=新增数据], Customer [cust_id=1, cust_name=程序员111]]

4.原生SQL映射为MAP:

@Test/*** 原生SQL查询(SQLQuery映射查询结果为map)*/public void fun6(){Session session = HibernateUtil.openSession();Transaction tx = session.beginTransaction();String sql = "select * from cst_customer";SQLQuery sqlQuery = session.createSQLQuery(sql);sqlQuery.setResultTransformer(Transformers.ALIAS_TO_ENTITY_MAP);System.out.println(sqlQuery.list());tx.commit();session.close();}

结果:

[{cust_phone=null, cust_name=测试名称1, cust_mobile=null, cust_linkman=null, cust_industry=null, cust_level=null, cust_source=null, cust_id=7}, {cust_phone=null, cust_name=测试名称2, cust_mobile=null, cust_linkman=null, cust_industry=null, cust_level=null, cust_source=null, cust_id=8}, {cust_phone=null, cust_name=测试名称3, cust_mobile=null, cust_linkman=null, cust_industry=null, cust_level=null, cust_source=null, cust_id=9}, {cust_phone=null, cust_name=测试名称4, cust_mobile=null, cust_linkman=null, cust_industry=null, cust_level=null, cust_source=null, cust_id=10}, {cust_phone=null, cust_name=测试名称5, cust_mobile=null, cust_linkman=null, cust_industry=null, cust_level=null, cust_source=null, cust_id=11}, {cust_phone=null, cust_name=测试名称6, cust_mobile=null, cust_linkman=null, cust_industry=null, cust_level=null, cust_source=null, cust_id=12}, {cust_phone=null, cust_name=测试名称7, cust_mobile=null, cust_linkman=null, cust_industry=null, cust_level=null, cust_source=null, cust_id=13}]

5.hibernate原生SQL进行插入操作

    @Test// 原生SQL执行插入操作public void test6() {// 1.获取与线程绑定的sessionSession session = HibernateUtils.getCurrentSession();// 2.开启事务Transaction tx = session.beginTransaction();String sql = "insert into user values('xxxx','李四',23)";;// 3.构造Query对象进行插入SQLQuery sqlQuery = session.createSQLQuery(sql);sqlQuery.executeUpdate();// 提交事务
        tx.commit();}

转载于:https://www.cnblogs.com/qlqwjy/p/9357369.html