正则: .*(((?i)phpsessid|sessionid)=[color=red][size=large].*?[/size][/color])(\?|&|$).*
str: http://www.foo.com/foo.html;jsessionid=1E6FEC0D14D044541DD84D2D013D29ED?param=1&another=2
结果
groups: 4
0: http://www.foo.com/foo.html;jsessionid=1E6FEC0D14D044541DD84D2D013D29ED?param=1&another=2
1: sessionid=1E6FEC0D14D044541DD84D2D013D29ED
2: sessionid
3: ?
问号去掉
正则: .*(((?i)phpsessid|sessionid)=[color=red][size=large].*[/size][/color])(\?|&|$).*
结果
groups: 4
0: http://www.foo.com/foo.html;jsessionid=1E6FEC0D14D044541DD84D2D013D29ED?param=1&another=2
1: sessionid=1E6FEC0D14D044541DD84D2D013D29ED?param=1&another=2
2: sessionid
3:
怎么解释这个问号的作用呢