isNotNull与isNotEmpty的区别

<isNotNull>

检查属性是否不为null

<isNotEmpty>

检查Collection.size()的值，属性的String或String.valueOf()值,是否不为null或不为空（“”或size() > 0）

----------------------使用----------------------

1. <!-- 分页查询返回列表 -->
2. <select id="getUserPrivacyPage" parameterClass="map" resultClass="hashmap">
3. select uid,`key`,`value` from ts_user_privacy
4. <dynamic prepend="WHERE">
5. <isNotEmpty prepend="AND" property="uid">
6. uid=#uid#
7. </isNotEmpty>
8. <isNotEmpty prepend="AND" property="key">
9. key=#key#
10. </isNotEmpty>
11. <isNotEmpty prepend="AND" property="value">
12. value=#value#
13. </isNotEmpty>
14. </dynamic>
15. <isNotEmpty prepend="order by " property="_order">
16. $_order$
17. </isNotEmpty>
18. <isNotEmpty prepend="limit " property="_limit">
19. #_limit._pstart#,#_limit._psize#
20. </isNotEmpty>
21. </select>

<!-- 修改记录 -->

1. <update id="updateUserPrivacy"  parameterClass="map">
2. update ts_user_privacy
3. <dynamic  prepend="set">
4. <isNotNull prepend=","  property="value"> `value`=#value# </isNotNull>
5. </dynamic>
6. where uid=#uid# AND `key`=#key#
7. </update>

http://huangqiqing123.iteye.com/blog/1668963