我真的找不到这种方法的内部构建方法
因此，我编写了一个用户定义的函数，并将其用于我的pig脚本中
就像这样-

public class convertToUTC extends EvalFunc<String> {
        @Override
        public String exec(final Tuple input) throws IOException {
            if (input == null || input.size() == 0) {
                return null;
            }
            try {
                String date = input.get(0).toString();
                Timestamp timestamp = Timestamp.valueOf(date);
                Calendar calendar = Calendar.getInstance();
                calendar.setTime(timestamp);
                calendar.add(Calendar.HOUR, 8);
                Timestamp UTCTimestamp = new Timestamp(calendar.getTime().getTime());
                return UTCTimestamp.toString();
            }
            catch (Exception e) {
                throw WrappedIOException.wrap("Caught exception processing input row ", e);
            }
        }
    }