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];