有关于IBatis中的statement

在这个标签里面
定义动态参数的时候
有时候用 #param#
有时候用 $param$

请问这两种有什么区别？？？？

以前遇到过:

http://forum.iteye.com/viewtopic.php?t=16152

去看了  谢谢
可是里面没有说原理
在哪种情况下用哪句？？？

Cliton Begin 在 iBATIS SQL Maps Developer Guide 有这个问题的说明呀:

找 Simple Dynamic SQL Elements  一节就可以了，很详细的。

本来想把原文贴上来，太长，还是自己找吧。

Despite the power of the full Dynamic Mapped Statement API discussed above, sometimes you just need a
simple, small piece of your SQL to be dynamic. For this, SQL statements and statements can contain
simple dynamic SQL elements to help implement dynamic order by clauses, dynamic select columns or
pretty much any part of the SQL statement. The concept works much like inline parameter maps, but uses
a slightly different syntax. Consider the following example:
<statement id=”getProduct” resultMap=”get-product-result”>
select * from PRODUCT order by $preferredOrder$
</statement>
In the above example the preferredOrder dynamic element will be replaced by the value of the
preferredOrder property of the parameter object (just like a parameter map);. The difference is that this is a
fundamental change to the SQL statement itself, which is much more serious than simply setting a
parameter value. A mistake made in a Dynamic SQL Element can introduce security, performance and
stability risks. Take care to do a lot of redundant checks to ensure that the simple dynamic SQL elements
are being used appropriately. Also, be mindful of your design, as there is potential for database specifics to
encroach on your business object model. For example, you may not want a column name intended for an
order by clause to end up as a property in your business object, or as a field value on your JSP page.
Simple dynamic elements can be included within <statements> and come in handy when there is a need to
modify the SQL statement itself. For example:
<statement id=”getProduct” resultMap=”get-product-result”>
SELECT * FROM PRODUCT
<dynamic prepend=”WHERE”>
<isNotEmpty property=”description”>
PRD_DESCRIPTION $operator$ #description#
</isNotEmpty>
</dynamic>
</statement>

  哪位牛牛帮忙简单的翻译翻译  E文实在是不行 看不太懂

啊啊 不用了不用了 已经看明白了
谢谢谢谢

知道了,其中$operator$ 对应参数类的一个属性.是这样的吧?

$operator$ #operator#都会从传入参数（基本类型、类、Map）中获取值。但是#operator#会作为生成的perparestatement中的一个占位符。