使用mybatis中foreach时:
collection 属性中为list;
List<User> find(@Param("param")List list);
<if test="paramMap.taxEidList != null">
and id in
<foreach collection="list" index="index" item="item" open="(" separator="," close=")">
'${item}'
</foreach>
</if>
collection 属性中为array;
List<User> find(@Param("param")Array arr);
<if test="param != null">
and id in
<foreach collection="array" index="index" item="item" open="(" separator="," close=")">
'${item}'
</foreach>
</if>
把集合都封装进map中,比如这里的list1,list2,都加入到集合中,key 为list1,list2,然后按照如下方式取出,collection 属性中为放入map时的key
List<User> find(@Param("param")Map<String> map);
<if test="param.list1 != null">
and id in
<foreach collection="param.list1" index="index" item="item" open="(" separator="," close=")">
'${item}'
</foreach>
</if>
<if test="param.list2 != null">
and id in
<foreach collection="param.list2" index="index" item="item" open="(" separator="," close=")">
'${item}'
</foreach>
</if>
再次详细的做了测试,传入多个list时,上面的这个方法3是无效的,你永远只能取出第一个有值的集合。这个问题我搞了两天才试出来。一堆垃圾文章! 解决方案: 这里建议你传递对象过来,比如Person对象,里面加入List list1;List list2;….这样,把对象传到mapper.xml中时,取法如下:
List<User> find(@Param("person")Person person);
<if test="person.list1 != null">
and id in
<foreach collection="person.list1" index="index" item="item" open="(" separator="," close=")">
'${item}'
</foreach>
</if>
<if test="person.list2 != null">
and id in
<foreach collection="person.list2" index="index" item="item" open="(" separator="," close=")">
'${item}'
</foreach>
</if>
还有,qtmd传List时collection属性只能为list!!!