NSJSONSerializaton没有返回结果

用了很多方法的都没有返回结果
先看一下代码:

json文件：

{ "speakers" : 
  [
    {
    "name":"Value",
    "picture": "URL VALUE",
    "business":"VALUE",
    "desc":"VALUE",
    "twitter": "URL VALUE"
    }                   
    {
           ...

    }
  ]
}

开始在一个dictionary中保存speaker属性
这个包含一个数组，有一些name，business属性

objective代码：

NSString *URLStr = @"URLofMyJsonFile";

NSURLRequest *JSONRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:[NSString stringWithString:URLStr ]]];

NSData *JSONData = [NSURLConnection sendSynchronousRequest:JSONRequest returningResponse:nil error:nil];

NSError *parsingError = nil;

NSDictionary *speakerDictionnary = [NSJSONSerialization JSONObjectWithData:JSONData options:0 error:&parsingError];

NSArray *speakersArray = [speakerDictionnary objectForKey:@"news"];

for (NSDictionary *oneSpeaker in speakersArray) {
    NSLog(@"The speakers's name is %@", [oneSpeaker objectForKey:@"name"]);
    NSLog(@"The speakers's business is %@", [oneSpeaker objectForKey:@"business"]);
    NSLog(@"The speakers's desc is %@", [oneSpeaker objectForKey:@"desc"]);
}