兼顾效率，iBatis一些非见用法(10条)

兼顾效率，iBatis一些非见用法(10条)

iBatis一些非见用法，基本上解决所有棘手问题，下面总结如下：

1、动态SQL片段

通过SQL片段达到代码复用

<!-- 动态条件分页查询 -->
<sql id="sql_count">
select count(*)
</sql>
<sql id="sql_select">
select *
</sql>
<sql id="sql_where">
from icp
<dynamic prepend="where">
<isNotEmpty prepend="and" property="name">
name like '%$name$%'
</isNotEmpty>
<isNotEmpty prepend="and" property="path">
path like '%path$%'
</isNotEmpty>
<isNotEmpty prepend="and" property="area_id">
area_id = #area_id#
</isNotEmpty>
<isNotEmpty prepend="and" property="hided">
hided = #hided#
</isNotEmpty>
</dynamic>
<dynamic prepend="">
<isNotNull property="_start">
<isNotNull property="_size">
limit #_start#, #_size#
</isNotNull>
</isNotNull>
</dynamic>
</sql>
<select id="findByParamsForCount" parameterClass="map" resultClass="int">
<include refid="sql_count"/>
<include refid="sql_where"/>
</select>
<select id="findByParams" parameterClass="map" resultMap="icp.result_base">
<include refid="sql_select"/>
<include refid="sql_where"/>
</select>

2、数字范围查询

所传参数名称是捏造所得，非数据库字段，比如_img_size_ge、_img_size_lt字段

<isNotEmpty prepend="and" property="_img_size_ge">
<![CDATA[
img_size >= #_img_size_ge#
]]>
</isNotEmpty>
<isNotEmpty prepend="and" property="_img_size_lt">
<![CDATA[
img_size < #_img_size_lt#
]]>
</isNotEmpty>

多次使用一个参数也是允许的

<isNotEmpty prepend="and" property="_now">
<![CDATA[
execplantime >= #_now#
]]>
</isNotEmpty>
<isNotEmpty prepend="and" property="_now">
<![CDATA[
closeplantime <= #_now#
]]>
</isNotEmpty>

3、时间范围查询

<isNotEmpty prepend="" property="_starttime">
<isNotEmpty prepend="and" property="_endtime">
<![CDATA[
createtime >= #_starttime#
and createtime < #_endtime#
]]>
</isNotEmpty>
</isNotEmpty>

4、in查询

<isNotEmpty prepend="and" property="_in_state">
state in ('$_in_state$')
</isNotEmpty>

5、like查询

<isNotEmpty prepend="and" property="chnameone">
(chnameone like '%$chnameone$%' or spellinitial like '%$chnameone$%')
</isNotEmpty>
<isNotEmpty prepend="and" property="chnametwo">
chnametwo like '%$chnametwo$%'
</isNotEmpty>

6、or条件

<isEqual prepend="and" property="_exeable" compareValue="N">
<![CDATA[
(t.finished='11'or t.failure=3)
]]>
</isEqual>

<isEqual prepend="and" property="_exeable" compareValue="Y">
<![CDATA[
t.finished in ('10','19') and t.failure<3
]]>
</isEqual>

7、where子查询

<isNotEmpty prepend="" property="exprogramcode">
<isNotEmpty prepend="" property="isRational">
<isEqual prepend="and" property="isRational" compareValue="N">
code not in
(select t.contentcode
from cms_ccm_programcontent t
where t.contenttype='MZNRLX_MA'
and t.programcode = #exprogramcode#)
</isEqual>
</isNotEmpty>
</isNotEmpty>

<select id="findByProgramcode" parameterClass="string" resultMap="cms_ccm_material.result">
select *
from cms_ccm_material
where code in
(select t.contentcode
from cms_ccm_programcontent t
where t.contenttype = 'MZNRLX_MA'
and programcode = #value#)
order by updatetime desc
</select>

9、函数的使用

<!-- 添加 -->
<insert id="insert" parameterClass="RuleMaster">
insert into rulemaster(
name,
createtime,
updatetime,
remark
) values (
#name#,
now(),
now(),
#remark#
)
<selectKey keyProperty="id" resultClass="long">
select LAST_INSERT_ID()
</selectKey>
</insert>
<!-- 更新 -->
<update id="update" parameterClass="RuleMaster">
update rulemaster set
name = #name#,
updatetime = now(),
remark = #remark#
where id = #id#
</update>

10、map结果集

<!-- 动态条件分页查询 -->
<sql id="sql_count">
select count(a.*)
</sql>
<sql id="sql_select">
select a.idvid,
a.img imgurl,
a.img_s imgfile,
b.vfilename vfilename,
b.namename,
c.idsid,
c.url url,
c.filenamefilename,
c.statusstatus
</sql>
<sql id="sql_where">
From secfiles c, juji b, videoinfo a
where
a.id = b. videoid
and b.id = c.segmentid
and c.status = 0
order by a.id asc,b.id asc,c.sortnum asc
<dynamic prepend="">
<isNotNull property="_start">
<isNotNull property="_size">
limit #_start#, #_size#
</isNotNull>
</isNotNull>
</dynamic>
</sql>
<!-- 返回没有下载的记录总数 -->
<select id="getUndownFilesForCount" parameterClass="map" resultClass="int">
<include refid="sql_count"/>
<include refid="sql_where"/>
</select>
<!-- 返回没有下载的记录 -->
<select id="getUndownFiles" parameterClass="map" resultClass="java.util.HashMap">
<include refid="sql_select"/>
<include refid="sql_where"/>
</select>

注意：在使用Map作为结果集返回类型时候，必须这么设置结果集类型resultClass="java.util.HashMap"，这时候，需要根据字段的名称来取值，值类型为Object，key类型为String，这点要注意了：

定义的DAO方法实现如下：

public List<Map<String,Object>> findUndownFiles(Map map) {
return getSqlMapClientTemplate().queryForList("secfiles.getUndownFiles", map);
}

通过DAO读取并操作Map结果集数据：

public void test_findUndownFiles() {
List<Map<String, Object>> co = ser.findUndownFiles(new HashMap());
StringBuilder s = new StringBuilder();
for (Map<String, Object> map : co) {
System.out.println("---------------------------");
for (Map.Entry<String, Object> entry : map.entrySet()) {
System.out.print(entry.getKey()+"/t");
System.out.println(entry.getValue());
}
}
}

打印结果：

---------------------------
sid1
vfilename200905252009235799
urlhttp://d18.v.iask.com/f/1/f47817a394730dc682e660b943e84cc41006606.flv
status0
filename200905252009235799-00.flv
imgfile200905252009234399.jpg
vid1
imgurlhttp://p4.v.iask.com/95/595/1757503_1.jpg
---------------------------
sid2130
vfilename2009062615063867492
urlhttp://lz.dhot.v.iask.com/f/1/0ee2ae8b973988f6a93c071c8045ca5217266409.mp4
status0
filename2009062615063867492-00.mp4
imgfile2009062615063825434.jpg
vid93
imgurlhttp://cache.mars.sina.com.cn/nd/movievideo//thumb/2/1502_120160.jpg
---------------------------
sid2131
vfilename2009062615064184076
urlhttp://lz5.dhot.v.iask.com/f/1/36d3dadacb8d6bda434a58e7418ad3cc19037464.flv
status0
filename2009062615064184076-00.flv
imgfile2009062615064136733.jpg
vid94
imgurlhttp://cache.mars.sina.com.cn/nd/movievideo//thumb/6/2106_120160.jpg