Mybatis中各种操作总结

Mybatis中各种操作总结

1.大于等于和小于等于的写法

大于等于
<![CDATA[ >= ]]>
小于等于
<![CDATA[ <= ]]>
例如:sql如下:
create_date_time <![CDATA[ >= ]]> #{startTime} and  create_date_time <![CDATA[ <= ]]> #{endTime}

2.参数遍历

index属性:记录遍历的次数。通过#{index}可以获取到是第几次遍历

1. 传入的参数为list的时候

 对应的Dao中的Mapper文件是:
public List<User> selectByIds(List<Integer> ids);
 
xml文件代码片段:
<select id="selectByIds" resultType="com.txw.pojo.User">
        select * from user where id in
        <foreach collection="list" index="index" item="item" open="(" separator="," close=")">
            #{item}
        </foreach>
</select>
 
 
2. 传入的参数为Array的时候

对应的Dao中的Mapper文件是:

public List<User> selectByIds(int[] ids);

 

xml文件代码片段: 
<select id="selectByIds" resultType="com.txw.pojo.User">
        select * from user where id in
        <foreach collection="array" index="index" item="item" open="(" separator="," close=")">
            #{item}
        </foreach>
    </select>
 
3. 传入的参数为Map的时候
 
对应的Dao中的Mapper文件是:

public List<User> selectByIds(Map<String, Object> params);

 
xml文件代码片段: 
<select id="selectByIds" resultType="com.txw.pojo.User">
        select * from user where  id in
        <foreach collection="ids" index="index" item="item" open="(" separator="," close=")">
            #{item}
        </foreach>
    </select>
 
map的时候需要注意的是:collection的值“ids”是存储在map中的key(比如:map.put("ids",ids));尤其需要注意;

4.当传参比较多,各种类型都有时

Dao层代码
List<Integer> getTodaySuccessList(@Param("vehiclestr") List<Integer> vehiclestr, @Param("btime") String btime, @Param("etime") String etime);

xml文件代码:
    <select id="getTodaySuccessList" resultType="java.lang.Integer">
        SELECT
            v.Status
        FROM videodownload v
        WHERE
            v.VehicleId IN
            <foreach collection="vehiclestr" index="index" item="item" open="(" separator="," close=")">
                #{item}
            </foreach>
            AND v.CreatedTime <![CDATA[ >= ]]> #{btime}
            AND v.CreatedTime <![CDATA[ <= ]]> #{etime}
    </select>

3.插入之后返回特定字段

<insert id="insertUser" parameterType="cn.itcast.mybatis.po.User">
	 	<!-- 
		将插入数据的主键返回,返回到user对象中
		
		=================SELECT LAST_INSERT_ID():得到刚insert进去记录的主键值,只适用与自增主键
		
		keyProperty:将查询到主键值设置到parameterType指定的对象的哪个属性
		order:SELECT LAST_INSERT_ID()执行顺序,相对于insert语句来说它的执行顺序
		resultType:指定SELECT LAST_INSERT_ID()的结果类型
		 -->
	 	<selectKey keyProperty="id" order="AFTER" resultType="java.lang.Integer">
	 		SELECT LAST_INSERT_ID()
	 	</selectKey>
	 	INSERT INTO user(username,birthday,sex,address) VALUES(#{username},#{birthday},#{sex},#{address}) 
	 </insert>

4.sql复用

	<select id="count" resultType="java.lang.Long">
        SELECT COUNT(1) AS total
        <include refid="TRACK_ACTIVE_SAFETY_PICTURE_PAGE_FROM_WITH_FUNCTION"/>
    </select>
    
    <sql id="TRACK_ACTIVE_SAFETY_PICTURE_PAGE_FROM_WITH_FUNCTION">
        FROM test 
        WHERE id = #{param}
    </sql>
posted @ 2021-07-08 10:10  CodeSweet  阅读(131)  评论(0编辑  收藏  举报