stringByAddingPercentEscapesUsingEncoding(只对 `#%^{}[]|\"<> 加空格共14个字符编码,不包括”&?”等符号), ios9将淘汰不要用以前那个[@"" stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding] 已经淘汰。建议用 stringByAddingPercentEncodingWithAllowedChar