springboot中mybatisplus配置xml写sql

springboot中mybatisplus配置xml写sql

1、编写Mapper文件，自定义方法

//@Mapper //这里如果不加mapper ，springboot启动的时候就得加@MapperScan("com.lxw.newdemo.mapper")
public interface UserInfoMapper extends BaseMapper<UserInfo> {
//    @Select("SELECT  * FROM user_info")//一般不用注解开发
    List<UserInfo> queryDemo(String sex);//自定义需要的方法
}

2、编写xml文件(1.namespace是mapper接口，2.id是方法名)绑定

<?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.lxw.newdemo.mapper.UserInfoMapper">

    <resultMap type="com.lxw.newdemo.dao.UserInfo" id="yingshe">
        <id  column="user_id" property="userId"/>
        <result column="user_name" property="userName"/>
        <result column="user_age" property="userAge"/>
        <result column="user_sex" property="userSex"/>
    </resultMap>

    <select id="queryDemo" resultMap="yingshe">
        SELECT * FROM user_info where user_sex = #{sex}
    </select>

</mapper>

3、在springboot配置类application.yaml中注册xml文件(后面两行是显示日志的sql语句)

mybatis-plus:
  mapper-locations: classpath:mapper/*.xml
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

4、测试：

@SpringBootTest
@RequiredArgsConstructor(onConstructor_={@Autowired})
@MapperScan("com.lxw.newdemo.mapper")
class NewDemoApplicationTests {

    private final UserInfoMapper userInfoMapper;

    @Test
    void contextLoads() {
//        final List<UserInfo> userInfos1 = userInfoMapper.selectList(null);
//        System.out.println(userInfos1);
        final List<UserInfo> userInfos2 = userInfoMapper.queryDemo("男");
        System.out.println("*******************************************");
        userInfos2.forEach(System.out::println);
        System.out.println("*******************************************");

    }

}

实体类最好直接写一遍映射，避免出错

@Data
@TableName("user_info")
public class UserInfo {
    @TableId(value = "user_id",type = IdType.AUTO)
    private Long userId;
    @TableField("user_name")
    private String userName;
    @TableField("user_age")
    private int userAge;
    @TableField("user_sex")
    private String userSex;
}

@TableField别名效果 value属性

使用MybatisPlus自动生成的方法时，可以用@TableField起别名

在xml写sql时，需要自己写as的sql或者写resultMap映射