最近在看iBatis时,想做用动态Sql做个分布。因为在做项目时用iBator工具生成没有分页的功能,只有一些我们常用的功能。所以要对生成后的代码做修改。我在Java高手真经的一书中看到有做了MySql SqlServer Oracle的分页。实现如下:
MySql-->
首先说说MySql的分页语句
select * from user where...order by... limit 10,25
根据以上的语句我们可以对ibator生成后的代码进行修改。
第一修改User_sqlMap.xml
修改前
<select id="ibatorgenerated_selectByExample" resultMap="ibatorgenerated_BaseResultMap"
parameterClass="com.demo.ibatis.beans.UserExample">
select ID, LOGIN_NAME, PASSWORD
from user
<isParameterPresent>
<include refid="user.ibatorgenerated_Example_Where_Clause" />
<isNotNull property="orderByClause">
order by $orderByClause$
</isNotNull>
</isParameterPresent>
</select>
修改后
<select id="ibatorgenerated_selectByExample" resultMap="ibatorgenerated_BaseResultMap"
parameterClass="com.demo.ibatis.beans.UserExample">
select ID, LOGIN_NAME, PASSWORD
from user
<isParameterPresent>
<include refid="user.ibatorgenerated_Example_Where_Clause" />
<isNotNull property="orderByClause">
order by $orderByClause$
</isNotNull>
[b]<isNotNull property="limitClauseStart">
limit
$limitClauseStart$,$limitClauseCount$
</isNotNull>[/b]
</isParameterPresent>
</select>
重要的是黑色的字体是添加到原来的xml中的。接下来修改UserExample.java
在该类中添加两个字段和相应的getter/setter方法
protected String limitClauseStart;//起始参数
protected String limitClauseCount;//数量参数
接下来就可以通过Dao调用selectByExample()方法测试,好的以上就是MySql的分页。SqlServer的分页比较难了,因为 SqlServer中没有limit的关键字。
看看SqlServer的分页语句,那当然 SqlServer人分布方法有很多种。这里我采用其中的一种。
语句如下:
SELECT TOP 页大小 *
FROM TestTable
WHERE (ID >=
(select max(id) from (SELECT TOP 页大小*页数 id
FROM 表
ORDER BY id) as t))
ORDER BY ID
接下来和上面的MySql一样也进行修改
修改xml
<select id="ibatorgenerated_selectByExample" resultMap="ibatorgenerated_BaseResultMap"
parameterClass="com.demo.ibatis.beans.UserExample">
[b] <isNotNull property="limitClauseStart">
SELETE TOP $limitClauseCount$ * FROM user where (ID NOT IN
(SELECT TOP $limitClauseStart$ ID
</isNotNull>[/b]
<isNull property="limitClauseStart">
SELETE *
</isNull>
FROM user
from user
<isParameterPresent>
<include refid="user.ibatorgenerated_Example_Where_Clause" />
<isNotNull property="orderByClause">
order by $orderByClause$
[b] <isNotNull property="limitClauseStart">
))order by $orderByClause$
</isNotNull>[/b]
</isNotNull>
</isParameterPresent>
</select>
接下来是ORacle的,和上面都是差不多的这里不多说。
语法:
select* from(select rownum tid,user.* FROM (select * from user where id>1 order by ID desc)user where where rownum<35) where tid>10;
修改Xml,
<select id="ibatorgenerated_selectByExample" resultMap="ibatorgenerated_BaseResultMap"
parameterClass="com.demo.ibatis.beans.UserExample">
[b] <isNotNull property="limitClauseStart">
select* from(select rownum tid,user.* FROM (
</isNotNull>[/b]
select * from user
<isParameterPresent>
<include refid="user.ibatorgenerated_Example_Where_Clause" />
<isNotNull property="orderByClause">
order by $orderByClause$
</isNotNull>
[b] <isNotNull property="limitClauseStart">
<![[CDATA )user where where rownum<$limitClauseCount$+$limitClauseStart$+1) where tid>$limitClauseStart$;]]>
</isNotNull>[/b]
</isParameterPresent>
</select>
好的以上就是这次的代码,如果有错的请帮我指点一下...