MyBatis注解开发

MyBatis常用注解

注解	对应XML	说明
@Insert	< insert>	新增SQL
@Update	< update>	更新SQL
@Delete	< delete>	删除SQL
@Select	< select>	查询SQL
@Param	–	参数映射
@Results	< resultMap>	结果映射
@Result	< id>< result>	字段映射

开发流程：
1.dao包下创建接口

public interface GoodsDAO {
    @Select("select * from t_goods where current_price between  #{min} and #{max} order by current_price limit 0,#{limt}")
    public List<Goods> selectByPriceRange(@Param("min") Float min ,@Param("max") Float max ,@Param("limt") Integer limt);

	@Insert("INSERT INTO t_goods(title, sub_title, original_cost, current_price, discount, is_free_delivery, category_id) VALUES (#{title} , #{subTitle} , #{originalCost}, #{currentPrice}, #{discount}, #{isFreeDelivery}, #{categoryId})")
    //
    @SelectKey(statement = "select last_insert_id()" , before = false , keyProperty = "goodsId" , resultType = Integer.class)
    public int insert(Goods goods);
    @Select("select * from t_goods")
    //
    @Results({
            //
          @Result(column = "goods_id" ,property = "goodsId" , id = true) ,
            //
            @Result(column = "title" ,property = "title"),
            @Result(column = "current_price" ,property = "currentPrice")
    })
    public List<GoodsDTO> selectAll();

2.mybatis-config.xml中添加mapper

<mapper class="dao.GoodsDAO"/>

or

<package name="dao"/>

3.测试查询方法selectByPriceRange

 	@Test
    public void testSelectByPriceRange() throws Exception {
        SqlSession session = null;
        try{
            session = MyBatisUtils.openSession();
            GoodsDAO goodsDAO = session.getMapper(GoodsDAO.class);
            List<Goods> list = goodsDAO.selectByPriceRange(100f, 500f, 20);
            System.out.println(list.size());
        }catch (Exception e){
            throw e;
        } finally {
            MyBatisUtils.closeSession(session);

        }
    }

4.测试插入方法insert

	@Test
    public void testInsert() throws Exception {
        SqlSession session = null;
        try{
            session = MyBatisUtils.openSession();
            Goods goods = new Goods();
            goods.setTitle("测试商品");
            goods.setSubTitle("测试子标题");
            goods.setOriginalCost(200f);
            goods.setCurrentPrice(100f);
            goods.setDiscount(0.5f);
            goods.setIsFreeDelivery(1);
            goods.setCategoryId(43);
            GoodsDAO goodsDAO = session.getMapper(GoodsDAO.class);
            //insert()方法返回值代表本次成功插入的记录总数
            int num = goodsDAO.insert(goods);
            session.commit();//提交事务数据
            System.out.println(goods.getGoodsId());
        }catch (Exception e){
            if(session != null){
                session.rollback();//回滚事务
            }
            throw e;
        }finally {
            MyBatisUtils.closeSession(session);
        }
    }

5.测试结果映射

	@Test
    public void testSelectAll() throws Exception {
        SqlSession session = null;
        try{
            session = MyBatisUtils.openSession();
            GoodsDAO goodsDAO = session.getMapper(GoodsDAO.class);
            List<GoodsDTO> list = goodsDAO.selectAll();
            System.out.println(list.size());
        }catch (Exception e){
            throw e;
        } finally {
            MyBatisUtils.closeSession(session);

        }
    }