深入浅出Ibatis.net查询方式(1)
这里我们按照ibatis.net提供的相关的方法来介绍其拥有的查询方式，后续会对其进行分类归纳总结
在iBatis.net中有一个ISqlMapper接口，它是和外界交流的核心接口，下面是该接口下设计的属性和方法
（可以放大查看该图片）
可以看到里面有很多重载的方法，这些方法是实际使用中需要重点关注的，掌握和熟悉这些方法，可以帮助开发人员高效实现业务，避免再造轮子。
QueryForObject
其用法及签名如下所示
Executes a Sql SELECT statement that returns that returns data to populate a single object instance.
The parameter object is generally used to supply the input data for the WHERE clause parameter(s) of the SELECT statement.
Overload List
Executes a Sql SELECT statement that returns that returns data to populate a single object instance. The parameter object is generally used to supply the input data for the WHERE clause parameter(s) of the SELECT statement.
object QueryForObject(String,Object);
Executes a Sql SELECT statement that returns a single object of the type of the resultObject parameter.
object QueryForObject(String,Object,Object);
Executes a Sql SELECT statement that returns that returns data to populate a single object instance. The parameter object is generally used to supply the input data for the WHERE clause parameter(s) of the SELECT statement.
T QueryForObject<T>(String,Object);
Executes a Sql SELECT statement that returns a single object of the type of the resultObject parameter.
T QueryForObject<T>(String,Object,ISqlMapper.T);
QueryForQbject通俗说其作用是将数据库中的一条记录以特定的方式呈现，相当于其它框架中的GetModel(string id)等方法。建议使用generic版本。
下面举两个例子
例子1
代码：
SqlMap.QueryForObject < Account >( "Account.SelectOne" , id )
在ibatis.net的配置文件中，由于启用了 useStatementNamespaces 设置为true,因此在上面的Account.SelectOne需要带上命名空间，命名空间的名字对应Account.xml中第一行namespace中的名称，此处为Account
Account.xml映射文件片段
< sqlMap namespace= " Account " xmlns= " http://ibatis.apache.org/mapping "
xmlns:xsi= " http://www.w3.org/2001/XMLSchema-instance " >
< alias >
< typeAlias alias= " Account " type= " theone.domain.Account,theone.domain " />
</ alias >
…
< select id= " SelectOne " parameterClass= " string " resultClass= " Account " >
select * from Accounts where Id=#Id#
</ select >
在 resultClass= " Account " 中，Account是设置的别名，简化缩写
例子2
代码
public Hashtable FindAllOrderById5 ()
{
return SqlMap . QueryForObject < Hashtable >( "Account.select-all2" , null );
}
Account.xml映射文件
< select id= " select-all2 " resultMap= " FindAllResult2 " >
select * from Accounts order by Id desc
</ select >
< resultMap id= " FindAllResult2 " class= " Hashtable " >
< result property= " Id " column= " Id " />
< result property= " Item " column= " Item " />
< result property= " Money " column= " Money " />
< result property= " Year " column= " Year " />
< result property= " Month " column= " Month " />
< result property= " Day " column= " Day " />
< result property= " FavoritorLevel " column= " FavoritorLevel " />
< result property= " CreatedOn " column= " CreatedOn " />
< result property= " ModifiedOn " column= " ModifiedOn " />
</ resultMap >
这个映射配置使得到的结果的每一条记录都映射成一个 Hashtable ，这个 Hashtable 中包含 9 个 Key
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