mybatis mapper中sql参数是list/array/map的写法

0. foreach

foreach主要用来迭代集合，通常用在in条件中，要注意collection属性的用法。

1. 参数是List

getByIds(List<Long> asList)
<select id="getByIds">
    select * from t_table t
    where t.id in
    <foreach collection="list" item="itemId" index="index" open="(" close=")" separator=",">
        #{itemId}
    </foreach>
</select>

2. 参数是Array

getByIds(Long[] asList)
<select id="getByIds">
    select * from t_table t
    where t.id in
    <foreach collection="array" item="itemId" index="index" open="(" close=")" separator=",">
        #{itemId}
    </foreach>
</select>

3. 参数是Map，那么所有的#{}里面都应该是这个map的key

getByIds(Map<String, Object> map)
<select id="getByIds">
    select * from t_table t
    <where>
        <if test="key1OfMap != null and key1OfMap != ''">
            t.id1 = #{key1OfMap}
        </if>
        <if test="keyListOfMap != null and keyListOfMap.length != 0">
            And t.id2 in
            <foreach collection="keyListOfMap" item="itemId" index="index" open="(" close=")" separator=",">
                #{itemId}
            </foreach>
        </if>
    </where>
</select>