Java SQL Timestamp format to String like "1969-12-31 19:25:12"

import java.sql.Timestamp;
import java.text.SimpleDateFormat;

public class Main {
  public static void main(String[] argv) {
    long time = 12312342;
    System.out.println(simpleDateTimeStr(time));
  }/*w  ww  . j  a v a 2  s.  c o  m*/

  private static SimpleDateFormat simpleDateTimeFormate = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

  public static String simpleDateTimeStr(long time) {
    if (time > 0) {
      return simpleDateTimeFormate.format(new Timestamp(time));
    } else {
      return "--:--";
    }
  }
}