mybatis判断汇合为空或者元素个数为零 ,mybatis判断list为空或null,在xml文件中,长久层写法:

 <if test="questionIds!= null and questionIds.size()>0" >       WHERE id in      <foreach collection="questionIds" index="index" item="item" open="(" separator="," close=")">            #{item}       </foreach> </if>

双软认证高企软件认证著作权 恒标