i: Case insensitive: 忽略大小寫(xiě)

f: First only. That is, replace/find/etc. only the first occurrence of something.

r: The substring to find is a regular expression.標(biāo)準(zhǔn)正則表達(dá)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.在正則表達(dá)式中允許空格和注釋。

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')} 

輸出結(jié)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積分兌換30元優(yōu)惠券

${str?replace('\\b\\d+積分','','r')}

輸出：兌換30元優(yōu)惠券

ps：freemarker的replace功能

替換字符串 replace 

${s?replace(‘ba', ‘XY' )} 
${s?replace(‘ba', ‘XY' , ‘規(guī)則參數(shù)')}

將s里的所有的ba替換成xy 規(guī)則參數(shù)包含: i r m s c f 具體含義如下: 

· i: 大小寫(xiě)不區(qū)分. 
· f: 只替換第一個(gè)出現(xiàn)被替換字符串的字符串 
· r:  XY是正則表達(dá)式 

· 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. 

· s: Enables dotall mode for regular expressions (same as Perl singe-line mode). In dotall 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.