MyBatis-Plus 自定义SQL

自定义SQL的方式

Annotation注解方式
XML配置文件方式

Annotation注解方式

直接先定义接口方法，然后在接口方法上面开发注解即可

package com.ledao.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.ledao.entity.BlogType;
import org.apache.ibatis.annotations.Select;

/**
 * @author LeDao
 * @company
 * @create 2021-07-22 22:15
 */
public interface BlogTypeMapper extends BaseMapper {

    /**
     * 根据id查找博客类型
     *
     * @param id
     * @return
     */
    @Select("select * from t_blogtype where id=#{id}")
    BlogType findById(Integer id);
}

XML配置文件方式

1、修改application.yml配置文件

mybatis-plus:
  # 如果是放在src/main/java目录下 classpath:/com/*/*/mapper/*Mapper.xml
  # 如果是放在resource目录 classpath:/mapper/**.xml
  mapper-locations: classpath:/mapper/**.xml

2、自定义接口

package com.ledao.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.ledao.entity.BlogType;

import java.util.List;
import java.util.Map;

/**
 * @author LeDao
 * @company
 * @create 2021-07-22 22:15
 */
public interface BlogTypeMapper extends BaseMapper<BlogType> {
    
    /**
     * 根据情况获取博客类型列表
     *
     * @param map
     * @return
     */
    List<BlogType> list(Map<String, Object> map);
}

3、xml文件实现

<?xml version="1.0" encoding="UTF-8"?>
<!--suppress ALL-->
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.ledao.mapper.BlogTypeMapper">
    <resultMap id="BlogResult" type="com.ledao.entity.BlogType">
        <result property="id" column="id"/>
        <result property="name" column="name"/>
        <result property="sortNum" column="sortNum"/>
    </resultMap>

    <select id="list" parameterType="map" resultMap="BlogResult">
        select *
        from t_blogtype
        <where>
            <if test="name != null and name != ''">
                and name like #{name}
            </if>
        </where>
        <if test="start != null and size != null">
            limit #{start},#{size}
        </if>
    </select>
</mapper>

4、测试代码

@Test
void list(){
	Map<String, Object> map = new HashMap<>(16);
	map.put("name", "%a%");
	List<BlogType> blogTypeList = blogTypeMapper.list(map);
	for (BlogType blogType : blogTypeList) {
		System.out.println(blogType.getId() + "," + blogType.getName() + "," + blogType.getSortNum());
	}
}