Mybatis使用if标签动态生成SQL语句的用法解析-----Mybatis框架

浅浅的花香味﹌ 2024-03-03 05:37 55阅读 0赞

>     <?xml version="1.0" encoding="UTF-8"?>
>     
>     <!DOCTYPE mapper
>             PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
>             "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
>     
>     <mapper namespace="com.powernode.mybatis.mappers.CarMapper">
>     
>     
>     
>     
>     
>     
>         <select id="selectByMultiCondition" resultType="Car">
>             select * from t_car where 1 = 1
>             <if test="brand != null and brand != ''">
>                 and brand like '%${brand}%'
>             </if>
>             <if test="guidePrice != null and guidePrice != ''">
>                 and guide_price > #{guidePrice}
>             </if>
>             <if test="carType != null and carType != ''">
>                 and car_type = #{carType}
>             </if>
>         </select>
>     </mapper>
> 
>     <?xml version="1.0" encoding="UTF-8"?>
>     
>     <!DOCTYPE mapper
>             PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
>             "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
>     
>     <mapper namespace="com.powernode.mybatis.mappers.CarMapper">
>     
>     
>     
>     
>     
>     
>         <select id="selectByMultiCondition" resultType="Car">
>             select * from t_car where 1 = 1
>             <if test="brand != null and brand != ''">
>                 and brand like '%${brand}%'
>             </if>
>             <if test="guidePrice != null and guidePrice != ''">
>                 and guide_price > #{guidePrice}
>             </if>
>             <if test="carType != null and carType != ''">
>                 and car_type = #{carType}
>             </if>
>         </select>
>     </mapper>

>     package com.powernode.mybatis.mappers;
>     
>     import com.powernode.mybatis.pojo.Car;
>     import org.apache.ibatis.annotations.Param;
>     
>     import java.util.List;
>     
>     public interface CarMapper
>     {
>         //多条件查询,根据汽车品牌指导价和汽车类型实现查询
>         List<Car> selectByMultiCondition(@Param("brand") String brand,@Param("guidePrice") Double guidePrice,@Param("carType") String carType);
>     
>     }
> 
>     package com.powernode.mybatis.mappers;
>     
>     import com.powernode.mybatis.pojo.Car;
>     import org.apache.ibatis.annotations.Param;
>     
>     import java.util.List;
>     
>     public interface CarMapper
>     {
>         //多条件查询,根据汽车品牌指导价和汽车类型实现查询
>         List<Car> selectByMultiCondition(@Param("brand") String brand,@Param("guidePrice") Double guidePrice,@Param("carType") String carType);
>     
>     }

>     package com.powernode.mybatis.Test;
>     
>     import com.powernode.mybatis.mappers.CarMapper;
>     import com.powernode.mybatis.pojo.Car;
>     import com.powernode.mybatis.utils.SqlSessionUtil;
>     import org.apache.ibatis.session.SqlSession;
>     import org.junit.Test;
>     import org.slf4j.Logger;
>     import org.slf4j.LoggerFactory;
>     
>     import java.util.List;
>     
>     public class TestCarMapper
>     {
>         private static final Logger logger = LoggerFactory.getLogger(TestCarMapper.class);
>         @Test
>         public void TestSelectByMultiCondition()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             List<Car> carList = mapper.selectByMultiCondition("比亚迪",3.0,"燃油车");
>             carList.forEach(car -> {
>                 logger.info(car.toString());
>             });
>             SqlSessionUtil.close(sqlSession);
>         }
>         @Test
>         public void TestNull()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             List<Car> carList = mapper.selectByMultiCondition(null,null,null);
>             carList.forEach(car -> {
>                 logger.info(car.toString());
>             });
>         }
>         @Test
>         public void TestNum()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             List<Car> carList = mapper.selectByMultiCondition("长安",null,null);
>             carList.forEach(car -> {
>                 logger.info(car.toString());
>             });
>         }
>     }
> 
>     package com.powernode.mybatis.Test;
>     
>     import com.powernode.mybatis.mappers.CarMapper;
>     import com.powernode.mybatis.pojo.Car;
>     import com.powernode.mybatis.utils.SqlSessionUtil;
>     import org.apache.ibatis.session.SqlSession;
>     import org.junit.Test;
>     import org.slf4j.Logger;
>     import org.slf4j.LoggerFactory;
>     
>     import java.util.List;
>     
>     public class TestCarMapper
>     {
>         private static final Logger logger = LoggerFactory.getLogger(TestCarMapper.class);
>         @Test
>         public void TestSelectByMultiCondition()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             List<Car> carList = mapper.selectByMultiCondition("比亚迪",3.0,"燃油车");
>             carList.forEach(car -> {
>                 logger.info(car.toString());
>             });
>             SqlSessionUtil.close(sqlSession);
>         }
>         @Test
>         public void TestNull()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             List<Car> carList = mapper.selectByMultiCondition(null,null,null);
>             carList.forEach(car -> {
>                 logger.info(car.toString());
>             });
>         }
>         @Test
>         public void TestNum()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             List<Car> carList = mapper.selectByMultiCondition("长安",null,null);
>             carList.forEach(car -> {
>                 logger.info(car.toString());
>             });
>         }
>     }