java Applet实现时钟
package com.huaxia.wang;import java.util.*;import java.awt.*;import java.applet.*;import java.text.*;/** * @目的：时钟的小程序 * @author Rachel Gollub * @modified Daniel Peek replaced circle drawing calculation, few more changes */public class Clock extends Applet implements Runnable { private volatile Thread timer; // The thread that displays clock private int lastxs, lastys, lastxm, lastym, lastxh, lastyh; // Dimensions used to draw hands private SimpleDateFormat formatter; // Formats the date displayed private String lastdate; // String to hold date displayed private Font clockFaceFont; // Font for number display on clock private Date currentDate; // Used to get date to display private Color handColor; // Color of main hands and dial private Color numberColor; // Color of second hand and numbers private int xcenter = 80, ycenter = 55; // Center position public void init() { int x,y; lastxs = lastys = lastxm = lastym = lastxh = lastyh = 0; formatter = new SimpleDateFormat ("EEE MMM dd hh:mm:ss yyyy", Locale.getDefault()); currentDate = new Date(); lastdate = formatter.format(currentDate); clockFaceFont = new Font("Serif", Font.PLAIN, 14); handColor = Color.blue; numberColor = Color.darkGray; try { setBackground(new Color(Integer.parseInt(getParameter("bgcolor"), 16))); } catch (NullPointerException e) { } catch (NumberFormatException e) { } try { handColor = new Color(Integer.parseInt(getParameter("fgcolor1"), 16)); } catch (NullPointerException e) { } catch (NumberFormatException e) { } try { numberColor = new Color(Integer.parseInt(getParameter("fgcolor2"), 16)); } catch (NullPointerException e) { } catch (NumberFormatException e) { } resize(300,300); // Set clock window size } // Paint is the main part of the program public void update(Graphics g) { int xh, yh, xm, ym, xs, ys; int s = 0, m = 10, h = 10; String today; currentDate = new Date(); formatter.applyPattern("s"); try { s = Integer.parseInt(formatter.format(currentDate)); } catch (NumberFormatException n) { s = 0; } formatter.applyPattern("m"); try { m = Integer.parseInt(formatter.format(currentDate)); } catch (NumberFormatException n) { m = 10; } formatter.applyPattern("h"); try { h = Integer.parseInt(formatter.format(currentDate)); } catch (NumberFormatException n) { h = 10; } // Set position of the ends of the hands xs = (int) (Math.cos(s * Math.PI / 30 - Math.PI / 2) * 45 + xcenter); ys = (int) (Math.sin(s * Math.PI / 30 - Math.PI / 2) * 45 + ycenter); xm = (int) (Math.cos(m * Math.PI / 30 - Math.PI / 2) * 40 + xcenter); ym = (int) (Math.sin(m * Math.PI / 30 - Math.PI / 2) * 40 + ycenter); xh = (int) (Math.cos((h*30 + m / 2) * Math.PI / 180 - Math.PI / 2) * 30 + xcenter); yh = (int) (Math.sin((h*30 + m / 2) * Math.PI / 180 - Math.PI / 2) * 30 + ycenter); // Get the date to print at the bottom formatter.applyPattern("EEE MMM dd HH:mm:ss yyyy"); today = formatter.format(currentDate); g.setFont(clockFaceFont); // Erase if necessary g.setColor(getBackground()); if (xs != lastxs || ys != lastys) { g.drawLine(xcenter, ycenter, lastxs, lastys); g.drawString(lastdate, 5, 125); } if (xm != lastxm || ym != lastym) { g.drawLine(xcenter, ycenter-1, lastxm, lastym); g.drawLine(xcenter-1, ycenter, lastxm, lastym); } if (xh != lastxh || yh != lastyh) { g.drawLine(xcenter, ycenter-1, lastxh, lastyh); g.drawLine(xcenter-1, ycenter, lastxh, lastyh); } // Draw date and hands g.setColor(numberColor); g.drawString(today, 5, 125); g.drawLine(xcenter, ycenter, xs, ys); g.setColor(handColor); g.drawLine(xcenter, ycenter-1, xm, ym); g.drawLine(xcenter-1, ycenter, xm, ym); g.drawLine(xcenter, ycenter-1, xh, yh); g.drawLine(xcenter-1, ycenter, xh, yh); lastxs = xs; lastys = ys; lastxm = xm; lastym = ym; lastxh = xh; lastyh = yh; lastdate = today; currentDate = null; } public void paint(Graphics g) { g.setFont(clockFaceFont); // Draw the circle and numbers g.setColor(handColor); g.drawArc(xcenter-50, ycenter-50, 100, 100, 0, 360); g.setColor(numberColor); g.drawString("9", xcenter-45, ycenter+3); g.drawString("3", xcenter+40, ycenter+3); g.drawString("12", xcenter-5, ycenter-37); g.drawString("6", xcenter-3, ycenter+45); // Draw date and hands g.setColor(numberColor); g.drawString(lastdate, 5, 125); g.drawLine(xcenter, ycenter, lastxs, lastys); g.setColor(handColor); g.drawLine(xcenter, ycenter-1, lastxm, lastym); g.drawLine(xcenter-1, ycenter, lastxm, lastym); g.drawLine(xcenter, ycenter-1, lastxh, lastyh); g.drawLine(xcenter-1, ycenter, lastxh, lastyh); } public void start() { timer = new Thread(this); timer.start(); } public void stop() { timer = null; } public void run() { Thread me = Thread.currentThread(); while (timer == me) { try { Thread.currentThread().sleep(100); } catch (InterruptedException e) { } repaint(); } } public String getAppletInfo() { return "Title: A Clock \n" + "Author: Rachel Gollub, 1995 \n" + "An analog clock."; } public String[][] getParameterInfo() { String[][] info = { {"bgcolor", "hexadecimal RGB number", "The background color. Default is the color of your browser."}, {"fgcolor1", "hexadecimal RGB number", "The color of the hands and dial. Default is blue."}, {"fgcolor2", "hexadecimal RGB number", "The color of the second hand and numbers. Default is dark gray."} }; return info; }}?