SNMP EventTime in Human Readable format in Java

Question

I have a stand alone java application that receives SNMP messages via an SNMP trap. I am using SNMP4J library in my application. In the SNMP message received, I need to convert

Answer 1

Maybe it's a bit late (you posted your question 6 years ago) but I recently got the same problem and found a general solution that takes into account:
1. The SNMP-reply may or may not report the offset from GMT
2. If the time zone is reported, it may be different from our local time zone

/**********************************************************************************************************************
 * Import definitions
 *********************************************************************************************************************/
import java.text.SimpleDateFormat;
import java.util.*;

/**********************************************************************************************************************
 * Class converting an SNMP DateAndTime into something readable.
 *********************************************************************************************************************/
public class ConvertDateAndTime
{
  /********************************************************************************************************************
   * This method converts the specified octet string into an array of bytes.
   * 
The string should be a number of 2-char hexadecimal bytes values separated by any non-hexadecimal character.
   *
   * @param  value_ipar The value returned by the equipment.
   * @return            The value as an array of bytes.
   * @throws Exception  Thrown in case of an error
   *******************************************************************************************************************/
  public static int[] octetStringToBytes(String value_ipar)
  {
    // ---------------------------
    // Split string into its parts
    // ---------------------------
    String[] bytes;
    bytes = value_ipar.split("[^0-9A-Fa-f]");

    // -----------------
    // Initialize result
    // -----------------
    int[] result;
    result = new int[bytes.length];

    // -------------
    // Convert bytes
    // -------------
    int counter;
    for (counter = 0; counter < bytes.length; counter++)
      result[counter] = Integer.parseInt(bytes[counter], 16);

    // ----
    // Done
    // ----
    return (result);

  } // octetStringToBytes

  /********************************************************************************************************************
   * This method converts the 'DateAndTime' value as returned by the device into internal format.
   * 
It returns null in case the reported year equals 0.
   * 
It throws an exception in case of an error.
   *******************************************************************************************************************/
  public static Date octetStringToDate(String value_ipar)
    throws Exception
  {
    // ---------------------------
    // Convert into array of bytes
    // ---------------------------
    int[] bytes;
    bytes = octetStringToBytes(value_ipar);

    // -----------------------
    // Maybe nothing specified
    // -----------------------
    if (bytes[0] == 0)
      return (null);

    // ------------------
    // Extract parameters
    // ------------------
    int year;
    int month;
    int day;
    int hour;
    int minute;
    int second;
    int deci_sec = 0;
    int offset = 0;
    year = (bytes[0] * 256) + bytes[1];
    month = bytes[2];
    day = bytes[3];
    hour = bytes[4];
    minute = bytes[5];
    second = bytes[6];
    if (bytes.length >= 8)
      deci_sec = bytes[7];
    if (bytes.length >= 10)
    {
      offset = bytes[9] * 60;
      if (bytes.length >= 11)
        offset += bytes[10];
      if (bytes[8] == '-')
        offset = -offset;
      offset *= 60 * 1000;
    }

    // ------------------------------------
    // Get current DST and time zone offset
    // ------------------------------------
    Calendar calendar;
    int      my_dst;
    int      my_zone;
    calendar = Calendar.getInstance();
    my_dst = calendar.get(Calendar.DST_OFFSET);
    my_zone = calendar.get(Calendar.ZONE_OFFSET);

    // ----------------------------------
    // Compose result
    // Month to be converted into 0-based
    // ----------------------------------
    calendar.clear();
    calendar.set(Calendar.YEAR, year);
    calendar.set(Calendar.MONTH, month - 1);
    calendar.set(Calendar.DAY_OF_MONTH, day);
    calendar.set(Calendar.HOUR_OF_DAY, hour);
    calendar.set(Calendar.MINUTE, minute);
    calendar.set(Calendar.SECOND, second);
    calendar.set(Calendar.MILLISECOND, deci_sec * 100);

    // ---------
    // Reset DST
    // ---------
    calendar.add(Calendar.MILLISECOND, my_dst);

    // -----------------------------------------------------------------------------------
    // If the offset is set, we have to convert the time using the offset of our time zone
    // -----------------------------------------------------------------------------------
    if (offset != 0)
    {
      int delta;
      delta = my_zone - offset;
      calendar.add(Calendar.MILLISECOND, delta);
    }

    // -------------
    // Return result
    // -------------
    return (calendar.getTime());

  } // octetStringToDate

  /********************************************************************************************************************
   *                                               M A I N
   *******************************************************************************************************************/
  public static void main(String[] args)
  {
    try
    {
      SimpleDateFormat format;
      format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss zzz");

      Date result;
      result = octetStringToDate("07 E2 02 02 12 0C 27 00"); // 18:12 in local time zone
      System.out.println(format.format(result)); // "2018-02-02 18:12:39 CET"

      result = octetStringToDate("07 E2 02 02 12 0C 27 00 2B 08 00"); // 18:12+08:00
      System.out.println(format.format(result)); // "2018-02-02 11:12:39 CET"

      result = octetStringToDate("07 E2 02 02 12 0C 27 00 2D 04 00"); // 18:12-04:00
      System.out.println(format.format(result)); // "2018-02-02 23:12:39 CET"

    }
    catch (Exception exception_ipar)
    {
      exception_ipar.printStackTrace();
    }

  } // main

} // class ConvertDateAndTime