在Java中设置文件创建时间戳

import java.io.*;
import java.util.*;
import java.text.*;
import javax.swing.*;

public class chdt{
    static File file;
    static JFrame frame = new JFrame("Input a file to change");
    public static void main(String[] args) {
        try{

            final JFileChooser fc = new JFileChooser();
            fc.setMultiSelectionEnabled(false);

            //BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
            //System.out.println("Enter file name with extension:");
            //String str = bf.readLine();
            JOptionPane.showMessageDialog(null,"Input a file to change.");
            frame.setSize(300,200);

            frame.setVisible(true);

            int retVal = fc.showOpenDialog(frame);
            if (retVal == JFileChooser.APPROVE_OPTION) {
                file = fc.getSelectedFile();
                frame.setVisible(false);
            } else {
                JOptionPane.showMessageDialog(null,"3RR0RZ!  You didn't input a file.");
                System.exit(0);
            }

            //System.out.println("Enter last modified date in 'dd-mm-yyyy-hh-mm-ss' format:");
            //String strDate = bf.readLine();
            String strDate = JOptionPane.showInputDialog("Enter last modified date in 'dd-mm-yyyy-hh-mm-ss' format:");

            SimpleDateFormat sdf = new SimpleDateFormat("dd-MM-yyyy-HH-mm-ss");
            Date date = sdf.parse(strDate);

            if (file.exists()){
                file.setLastModified(date.getTime());
                JOptionPane.showMessageDialog(null,"Modification is successful!");
            }
            else{
                JOptionPane.showMessageDialog(null,"File does not exist!  Did you accidentally it or what?");
            }
        }
        catch(Exception e){
            e.printStackTrace();
            JOptionPane.showMessageDialog(null,"3RR0RZ");
        }
    }
}