iOS如何轉換十三位的時間戳

//將十三位的時間戳轉換爲日期

- (NSString *)getDate:(NSString *)jsonDate

{

    //jsonDate相似這種/Date(1447659630000)/

    NSArray *strArray = [jsonDate componentsSeparatedByString:@"("];

    double timestampval =  [strArray[1] doubleValue]/1000;

    NSTimeInterval timestamp = (NSTimeInterval)timestampval;

    NSDate *updatetimestamp = [NSDate dateWithTimeIntervalSince1970:timestamp];

    NSDateFormatter* formatter = [[NSDateFormatter alloc] init];

    [formatter setDateFormat:@"yyyy-MM-dd"];

    NSString *dateString = [formatter stringFromDate:updatetimestamp];

    return dateString;

}