Mybats foreach multi select query, index loop, and cancel the and/or tag

demand ： Field is an array , Select multiple from the front-end drop-down code List to query

analysis ： If it is a single field, you can use in Inquire about , If mysql The version is 5.7 The above words can be used JSON Function query , Because the local database version is 5.6, I won't support it JSON function , So use like Inquire about

Because of the pull-down code Is a union , So use OR Inquire about , Use to <foreach> label

Default code <foreach> It's usually

<if test="query.brCode != null and query.brCode.size() > 0">
            and (
            <foreach collection="query.brCode" index="index" item="item">
                
               or rr.b_list LIKE CONCAT('%',#{item},'%')
            </foreach>
            )
        </if>

After that, we need to cancel the first or label , The thought of idnex The role of

Final realization ：

<if test="query.brCode != null and query.brCode.size() > 0">
            and (
            <foreach collection="query.brCode" index="index" item="item">
                <if test="index != 0 ">
                    or
                </if>
                br_list LIKE CONCAT('%',#{item},'%')
            </foreach>
            )
        </if>

Have a problem ：

mybaties java.lang.NumberFormatException: For input string: "{0=null}"

Because it has just been used #{index} Lead to