#pragma mark - 网络请求代理方式（异步）
- (IBAction)DelegateButtonDidClicked:(UIButton *)sender {

    // 1、拼接 urlString,网址里面必须写 http://
    NSString *urlString = @"http://ipad-bjwb.bjd.com.cn/DigitalPublication/publish/Handler/APINewsList.ashx?
date=20131129&startRecord=1&len=5&udid=1234567890&terminalType=Iphone&cid=213";

    // 2、依据字符串创建 URL(统一资源定位符)
    NSURL *url = [NSURL URLWithString:urlString];

    // 3、依据 url 创建 request 请求类的对象
    NSURLRequest *request = [NSURLRequest requestWithURL:url];

    // 4、请求数据（代理回调方式）遵守代理 <NSURLConnectionDataDelegate>
    [NSURLConnection connectionWithRequest:request delegate:self];
}

代理方法
client收到server的响应

#pragma mark | client收到server的响应
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    // 仅仅运行一次
    // 初始化 receiveData 对象
    self.receiveData = [NSMutableData data];
}

client收数据(并不是一次性所有拿到)

#pragma mark | client收数据(并不是一次性所有拿到)
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    // 每次返回的都是新数据
    // 拼接数据(请求一点 拼接一点)
    [self.receiveData appendData:data];
}

client接收数据完成

#pragma mark | client接收数据完成
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    // 解析数据
    NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:self.receiveData options:(NSJSONReadingMutableContainers) error:nil];


    NSArray *array = dict[@"news"];

    self.newsArray = [NSMutableArray array];

    for (NSDictionary *smallDict in array) {
        NewsModal *modal = [[NewsModal alloc] init];
        [modal setValuesForKeysWithDictionary:smallDict];
        [self.newsArray addObject:modal];
    }

    for (NewsModal *modal in self.newsArray) {
        NSLog(@"%@", modal.title);
    }
}

网络请求失败

#pragma mark | 网络请求失败
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    NSLog(@"%@", error);
}