1、匹配<b>和</b>之间的内容
<b>this is the test </b>
(?<=<(\w+)>)[\s\S]+?(?=</\1>)
2、匹配最外层的()
a+(b*(c+d))/e+f-(g/(h-i))*j
\(((?<Open>\()|(?<-Open>\))|[^()])*(?(Open)(?!))\)
3.匹配a标签
(?is)<a[^>]*?href=(['""]?)(?<url>[^'""\s>]+)\1[^>]*>(?<text>(?:(?!</?a\b).)*)</a>
4.新浪微博
@[\S]+
(https?|ftp)://[\S]+
#.+?#
参考: