hibernate的入门crud

package com.test;import com.demo.User;import org.hibernate.HibernateException;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.cfg.Configuration;import org.junit.Test;import java.util.Arrays;import java.util.List;/* * 没有借住HibernateUtil小工具 */public class crudTest { ???private static SessionFactory sessionFactory; // 工厂只有一个 根据配置文件来生成的 ???static { ???????Configuration cfg = new Configuration(); ???????// cfg.configure();//默认自动配置src下的hibernate.cfg.xml ???????// cfg.addResource("com/demo/user.hbm.xml");//增加一个映射文件 在配置里面已经配置过了） ???????// cfg.addClass(User.class);//去user类所在的包中查找名称为User，后缀为.hbm.xml的文件 ???????cfg.configure("hibernate.cfg.xml");// 读取指定的主配置文件（位置也可不需指定，默认自动查找src下的cfg.xml） ???????sessionFactory = cfg.buildSessionFactory(); // 生成session工厂 ???} ???@Test ???public void testSave() throws Exception { ???????User u = new User(); ???????u.setName("bb"); ???????u.setPassword("1563"); ???????u.setType("root"); ???????Session ses = sessionFactory.openSession(); // 打开一个新的session ???????Transaction ts = ses.beginTransaction(); // 开始事务---- 创建事务的对象ts ???????try { ???????????ses.save(u);// 往表user1存数据 ???????????ts.commit();// 提交事务 ???????} catch (HibernateException he) { ???????????he.printStackTrace(); ???????????System.out.println("死了"); ???????????ts.rollback();//事务的回滚 ???????} finally { ???????????ses.close(); ???????????sessionFactory.close(); ???????????System.out.println("插入成功"); ???????} ???} ???@Test ???public void testGet() throws Exception { ???????Session session = sessionFactory.openSession(); ???????Transaction tx = session.beginTransaction(); ???????User user = (User) session.get(User.class, 4);// 获取User表中的字段1 ???????System.out.println(user);// toString方法已经重写 [User:id=1,name=hoobey,password=456,type=admin] ???????tx.commit(); ???????session.close(); ???} ???@Test ???public void testHQL() { ???????Session session = sessionFactory.openSession(); ???????Transaction tx = session.beginTransaction(); ???????String hql = null; ???????// 执行查询 ???????// 1.简单的查询 ???????/* hql = "FROM User"; */ ???????// 2.带上过滤条件以及排序from User as u --使用别名 as可以省略 ???????/* hql="from User u where u.id = 1"; */ ???????// 3.指定select子句 ?????????hql = "select u.id , u.name from User u";//查询多个指定的列时 返回的是数组 输出使用Array.toString() ?????????List list = session.createQuery(hql).list(); ?????????for(Object obj : list){ ?????????????if(obj.getClass().isArray()){ ?????????????????System.out.println(Arrays.toString((Object[])obj));//查询返回的数组时 ???????????}else{ ?????????????????System.out.println(obj);//查询返回的是原属性的类型时 直接输出 } ???????????} ?????????} ???????// ---------------第二部分的学习----------------------------- ???????// 1，聚集函数：count(), max(), min(), avg(), sum()// ???????hql = "SELECT COUNT(*) FROM User"; // 返回的结果是Long型的 ???????// hql = "SELECT min(id) FROM Employee"; // 返回的结果是id属性的类型// ???????Number result = (Number) session.createQuery(hql).uniqueResult();// ???????System.out.println(result.getClass());// ???????System.out.println(result); ???????// 2，分组: Group By ... Having ???????// hql = "SELECT e.name,COUNT(e.id) FROM Employee e GROUP BY e.name"; ???????// hql = "SELECT e.name,COUNT(e.id) FROM Employee e GROUP BY e.name HAVING count(e.id)>1"; ???????// hql = "SELECT e.name,COUNT(e.id) FROM Employee e WHERE id<9 GROUP BY e.name HAVING count(e.id)>1"; ???????// --- ???????// hql = "SELECT e.name,COUNT(e.id) " + // ???????// "FROM Employee e " + // ???????// "WHERE id<9 " + // ???????// "GROUP BY e.name " + // ???????// "HAVING count(e.id)>1 " + // ???????// "ORDER BY count(e.id) ASC"; ???????// --- ???????// hql = "SELECT e.name,COUNT(e.id) AS c " + // ???????// "FROM Employee e " + // ???????// "WHERE id<9 " + // ???????// "GROUP BY e.name " + // ???????// "HAVING count(e.id)>1 " + // 在having子句中不能使用列别名 ???????// "ORDER BY c ASC"; // 在orderby子句中可以使用列别名 ???????// 3，连接查询 / HQL是面向对象的查询 ???????// >> 内连接（inner关键字可以省略） ???????// hql = "SELECT e.id,e.name,d.name FROM Employee e JOIN e.department d"; ???????// hql = "SELECT e.id,e.name,d.name FROM Employee e INNER JOIN e.department d"; ???????// >> 左外连接（outer关键字可以省略） ???????// hql = "SELECT e.id,e.name,d.name FROM Employee e LEFT OUTER JOIN e.department d"; ???????// >> 右外连接（outer关键字可以省略） ???????// hql = "SELECT e.id,e.name,d.name FROM Employee e RIGHT JOIN e.department d"; ???????// 可以使用更方便的方法 ???????// hql = "SELECT e.id,e.name,e.department.name FROM Employee e"; ???????// 4，查询时使用参数 ???????// >> 方式一：使用‘?‘占位 ???????// hql = "FROM Employee e WHERE id BETWEEN ? AND ?"; ???????// List list = session.createQuery(hql)// ???????// .setParameter(0, 5)// 设置参数，第1个参数的索引为0。 ???????// .setParameter(1, 15)// ???????// .list(); ???????// >> 方式二：使用变量名 ???????// hql = "FROM Employee e WHERE id BETWEEN :idMin AND :idMax"; ???????// List list = session.createQuery(hql)// ???????// .setParameter("idMax", 15)// ???????// .setParameter("idMin", 5)// ???????// .list(); ???????// 当参数是集合时，一定要使用setParameterList()设置参数值 ???????// hql = "FROM Employee e WHERE id IN (:ids)"; ???????// List list = session.createQuery(hql)// ???????// .setParameterList("ids", new Object[] { 1, 2, 3, 5, 8, 100 })// ???????// .list(); ???????// 5，使用命名查询 ???????// Query query = session.getNamedQuery("queryByIdRange"); ???????// query.setParameter("idMin", 3); ???????// query.setParameter("idMax", 10); ???????// List list = query.list(); ???????// 6，update与delete，不会通知Session缓存 ???????// >> Update// ????????int result = session.createQuery(//// ????????"UPDATE User e SET e.name=? WHERE user_id = 2")//// ????????.setParameter(0, "hghg")//// ????????.executeUpdate(); // 返回int型的结果，表示影响了多少行。// ????????System.out.println("result = " + result); ???????// ???????User user = (User)session.get(User.class, 1);// ???????System.out.println(user.getName()); ???????// >> Delete ???????/* ????????* int result = session.createQuery(// "DELETE FROM Employee e WHERE id>15")// .executeUpdate(); // 返回int型的结果，表示影响了多少行。 System.out.println("result = " + result); ????????*/ ???????// ----- 执行查询并显示结果 ???????// // List list = session.createQuery(hql).list(); ???????// for (Object obj : list) { ???????// if (obj.getClass().isArray()) { ???????// System.out.println(Arrays.toString((Object[]) obj)); ???????// } else { ???????// System.out.println(obj); ???????// } ???????// } ???????tx.commit(); ???????session.close(); ???}}