虽然在实际项目开发中，我们最经常使用的网络请求三方框架是AFNetworking，很多程序员不知道NSURLConnection而只知道AFNetworking，这就会带来很多局限性,NSURLConnection虽然在iOS9以后就被废弃了，可是作为apple的系统API，对于我们理解网络请求是非常有帮助的，首先我们来看下实例化api:
- (nullable instancetype)initWithRequest:(NSURLRequest *)request delegate:(nullable id)delegate startImmediately:(BOOL)startImmediately API_DEPRECATED("Use NSURLSession (see NSURLSession.h)", macos(10.5,10.11), ios(2.0,9.0), tvos(9.0,9.0)) __WATCHOS_PROHIBITED;
- (nullable instancetype)initWithRequest:(NSURLRequest *)request delegate:(nullable id)delegate API_DEPRECATED("Use NSURLSession (see NSURLSession.h)", macos(10.3,10.11), ios(2.0,9.0), tvos(9.0,9.0)) __WATCHOS_PROHIBITED;
+ (nullable NSURLConnection*)connectionWithRequest:(NSURLRequest *)request delegate:(nullable id)delegate API_DEPRECATED("Use NSURLSession (see NSURLSession.h)", macos(10.3,10.11), ios(2.0,9.0), tvos(9.0,9.0)) __WATCHOS_PROHIBITED;
三种实例化方法,都是在delegate里面接受数据,GET/POST请求在NSMutableURLRequest里面进行
//接收到响应
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
}
//接收到服务器返回的data
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
}
//connection请求完成
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
}
另外还有2个更简洁的方法，直接在block里面进行数据接受：
//1.异步请求
[NSURLConnection sendAsynchronousRequest:request
queue:[NSOperationQueue mainQueue]
completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {
//接受数据转json操作等等。。。
dispatch_async(dispatch_get_main_queue(), ^{
//刷新UI操作
});
}];
//2.同步请求
//响应
NSURLResponse *response = [[NSURLResponse alloc]init];
NSError *error;
//接受服务器返回的数据
NSData *responseData = [NSURLConnection sendSynchronousRequest:request
returningResponse:&response
error:&error];
//转json
id json = [NSJSONSerialization JSONObjectWithData:responseData
options:kNilOptions
error:nil];
这里要注意一下，接收到数据以后，UI方面的刷新都必须保证在主线程进行。
