网络请求 ---iOS

//1.url要访问的资源
NSURL *url = [NSURL URLWithString:@"http://www.baidu.com"];

//2.请求,要向服务器请求
NSURLRequest *request = [NSURLRequest requestWithURL:url];

NSURLSession *sesion = [NSURLSession sharedSession];

//3.等待服务器返回的二进制数
NSURLSessionDataTask *task = [sesion dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {

if (data != nil) {
NSLog(@"%@",data);
}
}];

[task resume];