OC实现：获取网络时间戳获取北京时间的方法

#pragma mark --请求网络时间戳

+ (void)getInternetDateWithSuccess:(void(^)(NSTimeInterval timeInterval))success failure:(void(^)(NSError *error))failure{
    //1.创建URL
    NSString *urlString = @"http://m.baidu.com";
    urlString = [urlString stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]];
     //2.创建request请求对象
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
    [request setURL:[NSURL URLWithString: urlString]];
    [request setCachePolicy:NSURLRequestReloadIgnoringCacheData];
    [request setTimeoutInterval:5];
    [request setHTTPShouldHandleCookies:FALSE];
    [request setHTTPMethod:@"GET"];
    //3.创建URLSession对象
    NSURLSession *session = [NSURLSession sharedSession];
     //4.设置数据返回回调的block
    NSURLSessionDataTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
       if (error == nil && response != nil) {
           //这么做的原因是简体中文下的手机不能识别“MMM”，只能识别“MM”
           NSArray *monthEnglishArray = @[@"Jan",@"Feb",@"Mar",@"Apr",@"May",@"Jun",@"Jul",@"Aug",@"Sept",@"Sep",@"Oct",@"Nov",@"Dec"];
           NSArray *monthNumArray = @[@"01",@"02",@"03",@"04",@"05",@"06",@"07",@"08",@"09",@"09",@"10",@"11",@"12"];
           NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;
           NSDictionary *allHeaderFields = [httpResponse allHeaderFields];
           NSString *dateStr = [allHeaderFields objectForKey:@"Date"];
           dateStr = [dateStr substringFromIndex:5];
           dateStr = [dateStr substringToIndex:[dateStr length]-4];
           dateStr = [dateStr stringByAppendingString:@" +0000"];
           //当前语言是中文的话，识别不了英文缩写
           for (NSInteger i = 0 ; i < monthEnglishArray.count ; i++) {
               NSString *monthEngStr = monthEnglishArray[i];