iBatis一些非见用法（相当实用）

兼顾效率，iBatis一些非见用法(10条)

2009-09-18 10:33:03

标签：iBatis 休闲职场

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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

<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

多次使用一个参数也是允许的

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

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

<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>
        
        <update id="update" parameterClass="RuleMaster">
                update rulemaster set
                name = #name#,
                updatetime = now(),
                remark = #remark#
                where id = #id#
        </update>

10、map结果集

<sql id="sql_count">
                select count(a.*)
        </sql>
        <sql id="sql_select">
                select a.id                vid,
                a.img             imgurl,
                a.img_s         imgfile,
                b.vfilename vfilename,
    b.name            name,
                c.id                sid,
                c.url             url,
                c.filename    filename,
                c.status        status
        </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>
        
        <select id="getUndownFilesForCount" parameterClass="map" resultClass="int">
                <include refid="sql_count"/>
                <include refid="sql_where"/>
        </select>
        
        <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()+" ");
                                System.out.println(entry.getValue());
                        }
                }
        }

打印结果：

---------------------------
sid  1
vfilename  200905252009235799
url  http://d18.v.iask.com/f/1/f47817a394730dc682e660b943e84cc41006606.flv
status  0
filename  200905252009235799-00.flv
imgfile  200905252009234399.jpg
vid  1
imgurl  http://p4.v.iask.com/95/595/1757503_1.jpg
---------------------------
sid  2130
vfilename  2009062615063867492
url  http://lz.dhot.v.iask.com/f/1/0ee2ae8b973988f6a93c071c8045ca5217266409.mp4
status  0
filename  2009062615063867492-00.mp4
imgfile  2009062615063825434.jpg
vid  93
imgurl  http://cache.mars.sina.com.cn/nd/movievideo//thumb/2/1502_120160.jpg
---------------------------
sid  2131
vfilename  2009062615064184076
url  http://lz5.dhot.v.iask.com/f/1/36d3dadacb8d6bda434a58e7418ad3cc19037464.flv
status  0
filename  2009062615064184076-00.flv
imgfile  2009062615064136733.jpg
vid  94
imgurl  http://cache.mars.sina.com.cn/nd/movievideo//thumb/6/2106_120160.jpg

由于iBatis从2.3.4版本后就改为MyIBatis了，为了研究源码方便，特上传2版本的源码和发布包。