hibernate (二) 实现简单的CRUD

  实体类:

public class User { 

private int id; 
private String username; 
private String password; 
private String nickname; 
private Date born; 
省略get，set方法 
｝

  User.hbm.xml

<hibernate-mapping package="org.th.model">
    <class name="User" table="t_user" >
          <id name="id"> 
               <!-- native是oracle和mysql合体(或者说是选择器)：当使用oracle是会选择sequence，mysql时会选择increment -->
            <generator class="native"></generator>
          </id>       
          <property name="username"></property>
          <property name="password"></property>
          <property name="nickname"></property>
          <property name="born" type="timestamp"></property>
    
    </class>
</hibernate-mapping>

 hibernate.cfg.xml

<session-factory>
	<!-- hibernate的方言，用来确定连接的数据库 -->
	<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
	
	<!-- 数据库驱动类  -->
	<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
    <!-- 数据库的连接字符串和用户名密码 -->
	<property name="connection.url">jdbc:mysql://localhost:3306/test_hibernate</property>
	<property name="connection.username">root</property>
	<property name="connection.password">root</property>
	
	<!--在使用hibernate，会现在sql语句  -->
	<property name="show_sql">true</property>
	<!-- 自动完成类到数据表的转换 -->
	<property name="hibernate.hbm2ddl.auto">update</property>
    
    <!-- 加入实体类的映射文件 -->
    <mapping resource="org/th/model/User.hbm.xml"/>
  </session-factory>

 测试类TestCRUD ：

public class TestCRUD {
	private static final SimpleDateFormat format = new SimpleDateFormat(
			"yyyy-MM-ddd");

	@Test
	public void testAdd() {
		Session session = null;
		try {
			session = HibernateUtil.openSession();

			session.beginTransaction();

			User user = new User();
			user.setBorn(format.parse("1978-12-21"));
			user.setUsername("李四");
			user.setPassword("123");
			user.setNickname("lisi");

			session.save(user);
			session.getTransaction().commit();
		} catch (Exception e) {
			e.printStackTrace();
			if (session != null)
				session.getTransaction().rollback();
		} finally {
			if (session != null)
				HibernateUtil.close(session);
		}
	}

	@Test
	public void testLoad() {
		Session session = null;
		try {
			session = HibernateUtil.openSession();
			User user = (User) session.load(User.class, 1);
			System.out.println(user);
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (session != null)
				HibernateUtil.close(session);
		}
	}

	@Test
	public void testUpdate() {
		Session session = null;
		try {
			session = HibernateUtil.openSession();

			session.beginTransaction();
			User user = (User) session.load(User.class, 2);
			user.setUsername("小黑哥");

			session.update(user);
			session.getTransaction().commit();
		} catch (Exception e) {
			e.printStackTrace();
			if (session != null)
				session.getTransaction().rollback();
		} finally {
			if (session != null)
				HibernateUtil.close(session);
		}
	}

	@Test
	public void testDelete() {
		Session session = null;
		try {
			session = HibernateUtil.openSession();

			session.beginTransaction();
			// User user=(User)session.load(User.class, 2);
			User user = new User();
			user.setId(3);

			session.delete(user);
			session.getTransaction().commit();
		} catch (Exception e) {
			e.printStackTrace();
			if (session != null)
				session.getTransaction().rollback();
		} finally {
			if (session != null)
				HibernateUtil.close(session);
		}
	}

	/**
	 * 
	 * @Title: testList
	 * @Description: 通过hibernate 的hql语句查询 返回list集合
	 * @param
	 * @return void 返回类型
	 * @throws
	 */
	@Test
	public void testList() {
		Session session = null;
		try {
			session = HibernateUtil.openSession();
			List<User> list = session.createQuery("from User").list();
			for (User user : list) {
				System.out.println(user);
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (session != null)
				HibernateUtil.close(session);
		}
	}

	/**
	 * 
	 * @Title: testPaging
	 * @Description: 通过hibernate 的hql语句查询 返回 分页之后 list集合,
	 * @param
	 * @return void 返回类型
	 * @throws
	 */
	@Test
	public void testPaging() {
		Session session = null;
		try {
			session = HibernateUtil.openSession();
			List<User> list = session.createQuery("from User")
					.setFirstResult(2).setMaxResults(2).list();
			for (User user : list) {
				System.out.println(user);
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (session != null)
				HibernateUtil.close(session);
		}
	}
}