Return string with new string containing URL?

I have string as follows:

String tweet = "#Insurgent is No. 1 in 72 of 76 markets where it opened this weekend #BoxOffice http://t.co/Y1Cdjl5JQ8 http://t.co/442WKZVcOq";

I want it to convert about string into following:

"#Insurgent is No. 1 in 72 of 76 markets where it opened this weekend #BoxOffice <a>http://ift.tt/1HSVeZ7; <a>http://ift.tt/1FPjIVP;";

So I want to check strings for web url and wrap it with anchor tags.

Dont downvote as i searched google but could not find solution Please help.