How to send POST and GET request?

I want to send my JSON to a URL (POST and GET).

NSMutableDictionary *JSONDict = [[NSMutableDictionary alloc] init];
[JSONDict setValue:"myValue" forKey:"myKey"];

NSData *JSONData = [NSJSONSerialization dataWithJSONObject:self options:kNilOptions error:nil];

My current request code isn't working.

NSMutableURLRequest *requestData = [[NSMutableURLRequest alloc] init];

[requestData setURL:[NSURL URLWithString:@"http://fake.url/"];];

[requestData setHTTPMethod:@"POST"];
[requestData setValue:postLength forHTTPHeaderField:@"Content-Length"];
[requestData setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
[requestData setValue:@"application/json" forHTTPHeaderField:@"Accept"];
[requestData setHTTPBody:postData];

Using ASIHTTPRequest is not a liable answer.