万年历程序

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Calendar;

import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class MainFrame extends JFrame {

 private static final long serialVersionUID = 1L;
 JPanel panel = new JPanel(new BorderLayout());
 JPanel panel1 = new JPanel();
 JPanel panel2 = new JPanel(new GridLayout(7, 7));
 JLabel[] label = new JLabel[49];
 JLabel y_label = new JLabel("年份");
 JLabel m_label = new JLabel("月份");
 JComboBox com1 = new JComboBox();
 JComboBox com2 = new JComboBox();
 int re_year, re_month;
 int x_size, y_size;
 String year_num;
 Calendar now = Calendar.getInstance(); // 实例化Calendar

 MainFrame() {
  super("实用万年历");
  setSize(300, 350);
  x_size = (int) (Toolkit.getDefaultToolkit().getScreenSize().getWidth());
  y_size = (int) (Toolkit.getDefaultToolkit().getScreenSize().getHeight());
  setLocation((x_size - 300) / 2, (y_size - 350) / 2);
  setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  panel1.add(y_label);
  panel1.add(com1);
  panel1.add(m_label);
  panel1.add(com2);
  for (int i = 0; i < 49; i++) {
   label[i] = new JLabel("", JLabel.CENTER);// 将显示的字符设置为居中
   panel2.add(label[i]);
  }
  panel.add(panel1, BorderLayout.NORTH);
  panel.add(panel2, BorderLayout.CENTER);
  panel.setBackground(Color.white);
  panel1.setBackground(Color.white);
  panel2.setBackground(Color.white);
  Init();//初始化方法
  com1.addActionListener(new ClockAction());
  com2.addActionListener(new ClockAction());

  setContentPane(panel);
  setVisible(true);
  setResizable(false);
 }

 // 事件处理
 class ClockAction implements ActionListener {
  public void actionPerformed(ActionEvent arg0) {
   int c_year, c_month, c_week;
   c_year = Integer.parseInt(com1.getSelectedItem().toString()); // 得到当前所选年份
   c_month = Integer.parseInt(com2.getSelectedItem().toString()) - 1; // 得到当前月份，并减1,计算机中的月为0－11
   c_week = use(c_year, c_month); // 调用函数use，得到星期几
   Resetday(c_week, c_year, c_month); // 调用函数Resetday
  }
 }

 public void Init() {
  int year, month_num, first_day_num;
  String log[] = { "日", "一", "二", "三", "四", "五", "六" };
  for (int i = 0; i < 7; i++) {
   label[i].setText(log[i]);
  }
  for (int i = 0; i < 49; i = i + 7) {
   label[i].setForeground(Color.red); // 将星期日的日期设置为红色
  }
  for (int i = 6; i < 49; i = i + 7) {
   label[i].setForeground(Color.green);// 将星期六的日期设置为绿色
  }
  for (int i = 1900; i < 3000; i++) {
   com1.addItem("" + i);
  }
  for (int i = 1; i < 13; i++) {
   com2.addItem("" + i);
  }
  month_num = now.get(Calendar.MONTH); // 得到当前时间的月份
  year = now.get(Calendar.YEAR); // 得到当前时间的年份
  com1.setSelectedItem("" + year); // 设置下拉列表显示为当前年
  com2.setSelectedItem("" + (month_num+1)); // 设置下拉列表显示为当前月
  first_day_num = use(year, month_num);
  Resetday(first_day_num, year, month_num);
 }

 public int use(int reyear, int remonth) {
  int week_num;
  now.set(reyear, remonth, 1); // 设置时间为所要查询的年月的第一天
  week_num = now.get(Calendar.DAY_OF_WEEK);// 得到第一天是星期中的第几天
  return week_num;
 }

 public void Resetday(int week_log, int year_log, int month_log) {
  int month_day_score; // 存储月份的天数
  int count;
  month_day_score = 0;
  count = 1;

  Calendar cal = Calendar.getInstance();
  cal.set(year_log, month_log, 1);
  month_day_score = cal.getActualMaximum(Calendar.DAY_OF_MONTH);// 月份的天数
  for (int i = 7; i < 49; i++) { // 初始化标签
   label[i].setText("");
  }
  week_log = week_log +6; // 将星期数加6，使显示正确
  month_day_score = month_day_score + week_log;
  for (int i = week_log; i < month_day_score; i++, count++) {
   label[i].setText(count + "");
  }
 }

 public static void main(String[] args) {
  JFrame.setDefaultLookAndFeelDecorated(true);
  new MainFrame();
 }
}

另外的类，就是在最底下有个动态显示系统当前时间的标签(简单的，可以不要这部分)

import java.awt.Canvas;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.text.SimpleDateFormat;
import java.util.Calendar;

class Clock extends Canvas implements Runnable {
 private static final long serialVersionUID = 3660124045489727166L;
 MainFrame mf;
 Thread t;
 String time;

 public Clock(MainFrame mf) {
  this.mf = mf;
  setSize(280, 40);
  setBackground(Color.white);
  t = new Thread(this); // 实例化线程
  t.start(); // 调用线程
 }

 public void run() {
  while (true) {
   try {
    Thread.sleep(1000); // 休眠1秒钟
   } catch (InterruptedException e) {
    System.out.println("异常");
   }
   this.repaint(100);
  }
 }

 public void paint(Graphics g) {
  Font f = new Font("宋体", Font.BOLD, 16);
  SimpleDateFormat SDF = new SimpleDateFormat("yyyy'年'MM'月'dd'日'HH:mm:ss");// 格式化时间显示类型
  Calendar now = Calendar.getInstance();
  time = SDF.format(now.getTime()); //得到当前日期和时间
  g.setFont(f);
  g.setColor(Color.orange);
  g.drawString(time, 45, 25);
 }
}