问题转化一下就是,NSString如何encoding。
var word = "Hello World! I love you"
//var encodeWord = word.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding) //这是已经废弃的方法
var encodeWord = word.stringByAddingPercentEncodingWithAllowedCharacters(NSCharacterSet.URLQueryAllowedCharacterSet())