MyBatis注解开发

　使用注解可以把原来放在XML文件中的配置信息和SQL语句放在程序中，小型敏捷开发的工程可以使用注解，而大型的需要团队协作的项目要使用XML

1.在dao目录创建一个GoodsDAO接口

package com.imooc.mybatis.dao;

import com.imooc.mybatis.dto.GoodsDTO;
import com.imooc.mybatis.entity.Goods;
import org.apache.ibatis.annotations.*;

import java.util.List;

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({
            //id
            @Result(column = "goods_id",property = "goodsId",id = true),
            //result
            @Result(column = "title",property = "title"),
            @Result(column = "current_price",property = "currentPrice"),
    })
    public List<GoodsDTO> selectAll();
}

 

2.在mybatis-config.xml中增加mapper声明

<mappers>
    <!--<mapper class="com.imooc.mybatis.dao.GoodsDAO"/>-->
    <package name="com.imooc.mybatis.dao"/>
</mappers>

3.测试

package com.imooc.mybatis;

import com.imooc.mybatis.dao.GoodsDAO;
import com.imooc.mybatis.entity.Goods;
import com.imooc.mybatis.utils.MyBatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import java.util.List;

//JUNIT单元测试类
public class MyBatisTestor {
    @Test
    public void testSelectAll() throws Exception {
        SqlSession session = null;
        try {
            session = MyBatisUtils.openSession();
            GoodsDAO goodsDAO = session.getMapper(GoodsDAO.class);
            List list = goodsDAO.selectAll();
            System.out.println(list.size());
        } catch (Exception e) {
            throw e;
        } finally {
            MyBatisUtils.closeSession(session);
        }
    }
    @Test
    public void testSelectByPriceRange() throws Exception {
        SqlSession session = null;
        try {
            session = MyBatisUtils.openSession();
            GoodsDAO goodsDAO = session.getMapper(GoodsDAO.class);
            List list = goodsDAO.selectByPriceRange(100f,500f,20);
            System.out.println(list.size());
        } catch (Exception e) {
            throw e;
        } finally {
            MyBatisUtils.closeSession(session);
        }
    }
    /**
     * 新增数据
     * @throws Exception
     */
    @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);
        }
    }

}