问iOS，检查http或https服务器是否正在特定端口上侦听

EN

- (void)testUrl:(NSString *)url
{
    // Create the request.
    NSURLRequest *theRequest=[NSURLRequest requestWithURL:[NSURL URLWithString:url]
                                              cachePolicy:NSURLRequestReloadIgnoringCacheData
                                          timeoutInterval:3.0];

    NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    NSHTTPURLResponse* httpResponse = (NSHTTPURLResponse*)response;
    int responseStatusCode = [httpResponse statusCode];

    NSLog(@"GOT STATUS CODE: %d", responseStatusCode);
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    NSLog(@"Done!");
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    NSLog(@"Connection failed! Error - %@ %@",
          [error localizedDescription],
          [[error userInfo] objectForKey:NSURLErrorFailingURLStringErrorKey]);
}