NSString *strUrl = @"https://www.api.com/api/info?t=123&sign=test123";
NSURL *reqURL = [NSURL URLWithString:strUrl];
NSLog(@"%@", [reqURL host]);
NSLog(@"%@", [reqURL path]);
NSLog(@"%@", [reqURL query]);
NSString *myString = myURL.absoluteString;
출처
https://stackoverflow.com/questions/8082719/convert-an-nsurl-to-an-nsstring