java 输入一个时间输出下一秒

package com.tinno.test;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;

import javax.swing.JOptionPane;

public class Test {
 public static void main(String[] args) throws Exception {

  String input = JOptionPane.showInputDialog(null, "Please input date(format: HHmmss)");
  final SimpleDateFormat sdf = new SimpleDateFormat("HHmmss");
  try{
   Calendar cal = Calendar.getInstance();
   cal.setTime(sdf.parse(input));
   cal.add(Calendar.SECOND, 1);
   System.out.println("Next second is: " + sdf.format(cal.getTime()));
  }catch(ParseException erroFmtExp){
   throw new Exception("Invalid date format, it must be HHmmss");
  }
 }

}