Java Swing 日期

package delftstack;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.LayoutManager;
import java.text.DateFormat;
import java.text.NumberFormat;
import java.text.SimpleDateFormat;
import java.util.Date;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.BorderFactory;
import javax.swing.JFormattedTextField;


public class Show_Date implements PropertyChangeListener {

    public static void main(String[] args) {
        Show_Date DateShow = new Show_Date();
        createWindow(DateShow);
    }

    private static void createWindow(Show_Date DateShow) {
        JFrame J_Frame = new JFrame("Show Date");
        J_Frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        createUI(J_Frame, DateShow);
        J_Frame.setSize(300, 200);
        J_Frame.setLocationRelativeTo(null);
        J_Frame.setVisible(true);
    }

    private static void createUI(final JFrame J_Frame, Show_Date DateShow) {
        JPanel J_Panel = new JPanel();
        LayoutManager Layout_Manager = new GridLayout(6,2);
        J_Panel.setLayout(Layout_Manager);
        J_Panel.setSize(200, 200);
        J_Panel.setBorder(BorderFactory.createTitledBorder("Date Format"));


        DateFormat Date_Format = new SimpleDateFormat("dd MMM YYYY");
        JFormattedTextField Today_Date = new JFormattedTextField(Date_Format);
        Today_Date.setName("Today");
        Today_Date.setColumns(10);
        Today_Date.setEditable(false);
        JLabel Today_Label = new JLabel("Date:");
        Today_Label.setLabelFor(Today_Date);
        Today_Date.setValue(new Date());

        J_Panel.add(Today_Label);
        J_Panel.add(Today_Date);
        JPanel Main_Panel = new JPanel();
        Main_Panel.add(J_Panel);

        J_Frame.getContentPane().add(Main_Panel, BorderLayout.CENTER);
    }

    @Override
    public void propertyChange(PropertyChangeEvent evt) {
        // TODO Auto-generated method stub

    }

}

package delftstack;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

class DatePick {
    int DATE_MONTH = java.util.Calendar.getInstance().get(java.util.Calendar.MONTH);
    int DATE_YEAR = java.util.Calendar.getInstance().get(java.util.Calendar.YEAR);;
    JLabel J_Label = new JLabel("", JLabel.CENTER);
    String DATE_DAY = "";
    JDialog J_Dialog;
    JButton[] J_Button = new JButton[49];

    public DatePick(JFrame J_Frame_Parent) {
        J_Dialog = new JDialog();
        J_Dialog.setModal(true);
        String[] Header = { "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday" };
        JPanel J_Panel1 = new JPanel(new GridLayout(7, 7));
        J_Panel1.setPreferredSize(new Dimension(700, 120));

        for (int i = 0; i < J_Button.length; i++) {
            final int selection = i;
            J_Button[i] = new JButton();
            J_Button[i].setFocusPainted(false);
            J_Button[i].setBackground(Color.white);
            if (i > 6)
                J_Button[i].addActionListener(new ActionListener() {
                    public void actionPerformed(ActionEvent ae) {
                        DATE_DAY = J_Button[selection].getActionCommand();
                        J_Dialog.dispose();
                    }
                });
            if (i < 7) {
                J_Button[i].setText(Header[i]);
                J_Button[i].setForeground(Color.red);
            }
            J_Panel1.add(J_Button[i]);
        }
        JPanel J_Panel2 = new JPanel(new GridLayout(1, 3));
        JButton Previous_Button = new JButton("<< Previous");
        Previous_Button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent ae) {
                DATE_MONTH--;
                Display_Date();
            }
        });
        J_Panel2.add(Previous_Button);
        J_Panel2.add(J_Label);
        JButton Next_Button = new JButton("Next >>");
        Next_Button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent ae) {
                DATE_MONTH++;
                Display_Date();
            }
        });
        J_Panel2.add(Next_Button);
        J_Dialog.add(J_Panel1, BorderLayout.CENTER);
        J_Dialog.add(J_Panel2, BorderLayout.SOUTH);
        J_Dialog.pack();
        J_Dialog.setLocationRelativeTo(J_Frame_Parent);
        Display_Date();
        J_Dialog.setVisible(true);
    }

    public void Display_Date() {
        for (int i = 7; i < J_Button.length; i++)
            J_Button[i].setText("");
        java.text.SimpleDateFormat Simple_Date_Format = new java.text.SimpleDateFormat(
                "MMMM yyyy");
        java.util.Calendar Calendar = java.util.Calendar.getInstance();
        Calendar.set(DATE_YEAR, DATE_MONTH, 1);
        int Day_Of_Week = Calendar.get(java.util.Calendar.DAY_OF_WEEK);
        int Days_In_Month = Calendar.getActualMaximum(java.util.Calendar.DAY_OF_MONTH);
        for (int i = 6 + Day_Of_Week, Day = 1; Day <= Days_In_Month; i++, Day++)
            J_Button[i].setText("" + Day);
        J_Label.setText(Simple_Date_Format.format(Calendar.getTime()));
        J_Dialog.setTitle("Date Picker");
    }

    public String Set_Picked_Date() {
        if (DATE_DAY.equals(""))
            return DATE_DAY;
        java.text.SimpleDateFormat Simple_Date_Format = new java.text.SimpleDateFormat(
                "dd-MM-yyyy");
        java.util.Calendar Calendar = java.util.Calendar.getInstance();
        Calendar.set(DATE_YEAR, DATE_MONTH, Integer.parseInt(DATE_DAY));
        return Simple_Date_Format.format(Calendar.getTime());
    }
}

public class Date_Picker {
    public static void main(String[] args) {
        JLabel J_Label = new JLabel("Date Selected:");
        final JTextField J_Text_Field = new JTextField(20);
        JButton J_Button = new JButton("Choose the Date");
        JPanel J_Panel = new JPanel();
        J_Panel.add(J_Label);
        J_Panel.add(J_Text_Field);
        J_Panel.add(J_Button);
        final JFrame J_Frame = new JFrame();
        J_Frame.getContentPane().add(J_Panel);
        J_Frame.pack();
        J_Frame.setVisible(true);
        J_Button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent ae) {
                J_Text_Field.setText(new DatePick(J_Frame).Set_Picked_Date());
            }
        });
    }
}