Ant: propertyregex

代码

<propertyregex property="pack.name"
		              input="package.1.name"
		              regexp="(package)\.\d\.(name)"
		              select="\1.DEF.\2"
		              casesensitive="false" />
<echo>***************${pack.name}</echo>

看到这段代码，理解了半天才明白。参照PropertyRegex

如果input的内容与regexp匹配，那么就将input的内容按照regexp里的()分组，有几个()就有几个分组，替换掉select里的\1 \2等。替换后，返回select里的值。 ( ) 标记一个子表达式的开始和结束位置。子表达式可以获取供以后使用。

Select expressions

• \0 代表整个input的值
• \1 代表第一个分组
• \2 代表第二个分组
• 等等...

所以上段代码的解释就简单了，input的值为"package.1.name"符合regexp里的正则表达式（\d 代表一个数字），并且regexp表达式里有两个()，即(package) (name)，分别替换掉select里的\1 \2.所以返回值是  package.DEF.name。

<pre name="code" class="html"><propertyregex property="pack.name"
				              input="package.1.name"
				              regexp="(package)\.\d\.(name)"
				              select="\0.DEF.\1.\2"
				              casesensitive="false" />
<echo>***************${pack.name}</echo>

运行结果：
package.1.name.DEF.package.name

Parameters

Attribute	Description	Required
property	The name of the property to set.	Yes.
override	If the property is already set, should we change it's value. Can be true or false	No. Defaults to false
input	The input string to be processed	Yes.
regexp	The regular expression which is matched in the input string.	Yes (can be specified in a <regexp> subelement).
select	A pattern which indicates what selection pattern you want in the returned value. This uses the substitution pattern syntax to indicate where to insert groupings created as a result of the regular expression match.	Yes, unless a replace is specified
replace	A regular expression substitition pattern, which will be used to replace the given regular expression in the input string.	Yes, unless a select is specified
casesensitive	Should the match be case sensitive	No. default is "true".
global	Should a replacement operation be performed on the entire string, rather than just the first occurance	No. default is false.
defaultValue	The value to set the output property to, if the input string does not match the specific regular expression.	No.