使用URLSession进程GET请求

构建URL网络地址

NSURL *url = [NSURL URLWithString:@"http://www.weather.com.cn/data/sk/101010300.html"];

构建网络请求对象 NSURLRequest

NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:url];

//设置请求方式 GET
request.HTTPMethod = @"GET";

//设置请求的超时时间
request.timeoutInterval = 60;

//请求头
[request setValue:<#(nullable NSString *)#> forHTTPHeaderField:<#(nonnull NSString *)#>];

//请求体
request.HTTPBody

通过配置对象构造网络会话 NSURLSession

NSURLSession *session = [NSURLSession sharedSession];

创建网络任务 NSURLSessionTask

 NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        NSLog(@"网络请求完成");
        
        //获取响应头
        //将响应对象 转化为NSHTTPURLResponse对象
        NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;
        //获取网络连接的状态码
        //  200 成功  404 网页未找到
        NSLog(@"状态码:%li", httpResponse.statusCode);
        if (httpResponse.statusCode == 200) {
            NSLog(@"请求成功");
        }
        //请求头
        NSLog(@"响应头:%@", httpResponse.allHeaderFields);
        //获取响应体
        //对响应体进行JSON解析
        if (data) {
            
            NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:nil][@"weatherinfo"];
//            NSLog(@"响应体数据:%@", dic);
            NSArray *array = dic.allKeys;
            for (NSString *key in array) {
                NSLog(@"%@:%@", key, dic[key]);
            }
        }
        
        
    }];

发起网络任务

[dataTask resume];