replace(param1,param2,param3)
param1 正则表达式；param2 将匹配的字符替换成指定字符；param3 模式
param3 参数如下
| 模式 | i | r | m | s | c | f |
| replace | 支持 | 支持 | 只和r 组合 | 只和r 组合 | 只和r 组合 | 支持 |
模式解释：
i: Case insensitive: 忽略大小写
f: First only. That is, replace/find/etc. only the first occurrence of something.
r: The substring to find is a regular expression.标准正则表达式（http://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html ）
m: Multi-line mode for regular expressions. In multi-line mode the expressions ^ and $ match just after or just before, respectively, a line terminator or the end of the string. By default these expressions only match at the beginning and the end of the entire string. Note that ^ and $ doesn‘t match the line-break character itself.
s: Enables dot-all mode for regular expressions (same as Perl singe-line mode). In dot-all mode, the expression . matches any character, including a line terminator. By default this expression does not match line terminators.
c: Permits whitespace and comments in regular expressions.在正则表达式中允许空格和注释。
范例如下：
<#assign s = ‘foo bAr baar‘>
${s?replace(‘ba‘, ‘XY‘)}
i: ${s?replace(‘ba‘, ‘XY‘, ‘i‘)}
if: ${s?replace(‘ba‘, ‘XY‘, ‘if‘)}
r: ${s?replace(‘ba*‘, ‘XY‘, ‘r‘)}
ri: ${s?replace(‘ba*‘, ‘XY‘, ‘ri‘)}
rif: ${s?replace(‘ba*‘, ‘XY‘, ‘rif‘)}
输出结果：
foo bAr XYar i: foo XYr XYar if: foo XYr baar r: foo XYAr XYr ri: foo XYr XYr rif: foo XYr baar
更多范例：
原文：str = 2积分兑换30元优惠券
${str?replace(‘\\b\\d+积分‘,‘‘,‘r‘)}
输出：兑换30元优惠券
更多信息可以参考：
http://freemarker.org/docs/ref_builtins_string.html#ref_builtin_replace