.net18位时间戳转化为java Date对象

public class DateUtils {
 
 private static final long TICKS_AT_EPOCH = 621355968000000000L;
 private static final long TICKS_PER_MILLISECOND = 10000;
 private static TimeZone timeZone = TimeZone.getDefault();
 
 public static Date fromDnetToJdate(String str){ 
  if(!"0".equals(str)){
   Calendar calendar = Calendar.getInstance(timeZone);
   calendar.setTimeInMillis((Long.parseLong(str)-TICKS_AT_EPOCH)/TICKS_PER_MILLISECOND);
   calendar.setTimeInMillis(calendar.getTimeInMillis()-calendar.getTimeZone().getRawOffset());
   return calendar.getTime();
  }else{
   return null;
  }
    
 }
}