使用NSDate进行时间转换

Question

我有来自日期的字符串

 formattedDateString: 2014-03-31 15:00:11

然后我用

  NSDate *newDate = [dateFormatter dateFromString:formattedDateString];

我得到了

formattedDate 2014-03-31 12:00:11 +0000

我失去了3个小时。哪里不好？

完整代码

             NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
        [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
        [dateFormatter setTimeZone:[NSTimeZone systemTimeZone]];
        NSDate *date = [NSDate dateWithTimeIntervalSince1970:[item[@"date"] doubleValue]];
        // Divided by 1000 (i.e. removed three trailing zeros) ^^^^^^^^
        NSString *formattedDateString = [dateFormatter stringFromDate:date];
        NSDate *newDate = [dateFormatter dateFromString:formattedDateString];