1.GET请求

self.dataArray = [NSMutableArray array];
NSURL *url = [NSURL URLWithString:HTTPURL];
NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *dataTask = [session dataTaskWithURL:url completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
 if (error) {
            NSLog(@"请求失败");
        }else{
            NSDictionary *diction = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:nil];
            for (NSDictionary *dic in diction) {
                NEWS *news = [[NEWS alloc] init];
                [news setValuesForKeysWithDictionary:dic];
                [self.dataArray addObject:news];
            }
        }
    }];       
[dataTask resume];

2.POST请求

- (void)loadData{
    NSString *string = @"http://ipad-bjwb.bjd.com.cn/DigitalPublication/publish/Handler/APINewsList.ashx";
    NSURL * url = [NSURL URLWithString:string];
    NSURLSession *session = [NSURLSession sharedSession];
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc]initWithURL:url];
    request.HTTPMethod = @"POST";
    NSString *dataString = @"date=20151031&startRecord=1&len=5&udid=1234567890&terminalType=Iphone&cid=213";
    NSData *data = [dataString dataUsingEncoding:NSUTF8StringEncoding];
    request.HTTPBody = data;
    NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        if (error) {
            NSLog(@"请求失败");
        }else {
            NSDictionary *diction = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:nil];
            for (NSDictionary *dic in diction[@"news"]) {
                NEWS *news = [[NEWS alloc] init];
                [news setValuesForKeysWithDictionary:dic];
                [self.dataArray addObject:news];
            }
            NSLog(@"%@",self.dataArray);
        }
    }];
    [dataTask resume];
}

注意:
在解析数据的时候,创建news对象的时候,必须要for循环的内部创建,否则,数组中的数据将都一样.