iOS 7开发之NSURLSession vs NSURLConnection

通过一个简单的联网获取JSON数据并将其解析 

举个例子 获取伦敦的天气数据

NSString*londonWeatherUrl =@"http://api.openweathermap.org/data/2.5/weather?q=London,uk"; 

//这里是使用NSURLConnection联网的方法

NSURLRequest*request = [NSURLRequestrequestWithURL:[NSURLURLWithString:londonWeatherUrl]];

[NSURLConnectionsendAsynchronousRequest:requestqueue:[NSOperationQueuemainQueue]completionHandler:^(NSURLResponse*response,

NSData*data,

NSError*connectionError) {// handle response

}] 

//通过NSURLSession联网的方法

NSURLSession*session = [NSURLSession sharedSession];
[[session dataTaskWithURL:[NSURLURLWithString:londonWeatherUrl]

completionHandler:^(NSData*data,NSURLResponse*response,

NSError*error) {

// handle response

}] resume]; 

// Use AFNetworking

NSURLRequest *request = [NSURLRequest requestWithURL:
[NSURL URLWithString:londonWeatherUrl]];

AFJSONRequestOperation *operation =
[AFJSONRequestOperation JSONRequestOperationWithRequest:request

success:^(NSURLRequest *request,NSHTTPURLResponse *response,

id JSON) {// handle response

} failure:nil];[operation start];