Hibernate_get和load的區別

1.get和load的區別

 *  get不支持lazy ,load支持lazy

 * 採用get加載數據如果沒有匹配的數據返回null而load則拋出異

    /**
	 * 採用get如果數據庫沒有就返回null
	 */
	public static void testReadByGetMethod02() {
		Session session = null;
		try {
			//
			session = HibernateSessionFactory.getSession();
			session.beginTransaction();
			Users user = (Users) session.get(Users.class,
					"402881123dba6017013dba6019490001");
			session.getTransaction().commit();
		} catch (Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		} finally {
			HibernateSessionFactory.closeSession();
		}
	}

	/**
	 * 採用load,延遲加載只有真正用到這個對象的時候才加載(執行sql)
	 */
	public static void testReadByLoadMethod01() {
		Session session = null;
		try {
			session = HibernateSessionFactory.getSession();
			session.beginTransaction();
			//這個時候不執行sql
			Users user = (Users) session.load(Users.class,
					"402881123dba6017013dba6019490001");
			
			//這個時候執行sql
			System.out.println("user_name:"+user.getUserName());
			session.getTransaction().commit();
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			HibernateSessionFactory.closeSession();
		}
	}

	/**
	 * 採用Load加載數據如果數據庫中沒有響應的數據，那麼拋出異常
	 */
	public static void testReadByLoadMethod02() {
		Session session = null;
		try {
			session = HibernateSessionFactory.getSession();
			session.beginTransaction();
            Users user=(Users)session.load(Users.class,"aaaaa");
			session.getTransaction().commit();
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			HibernateSessionFactory.closeSession();
		}
	}