Java编写时钟 Applet 程序

简单分析：

package clockApplet;

import java.applet.Applet;
import java.awt.Color;
import java.awt.Graphics;
import java.util.Calendar;
import java.util.GregorianCalendar;

public class ClockApplet extends Applet implements Runnable {
    /* 成员变量 */
    int x = 0, y = 0, r = 100; // （x,y）为(0,0)点，表示原点
    int h, m, s; // 时,分,秒
    double rad = Math.PI / 180; //  1°

    /* 初始化函数 */
    public void init() {
        Calendar now = new GregorianCalendar(); /*
                                                 * GregorianCalendar（标准阳历）
                                                 * 是Calendar（日历）【国际环境下都能运行的程序】
                                                 * 的子类
                                                 */
        s = now.get(Calendar.SECOND) * 6; // 秒针转换成角度：1秒，秒针动一次，转动6°
        m = now.get(Calendar.MINUTE) * 6; // 分针转换为角度：1分，分针动一次，转动6°
        h = now.get(Calendar.HOUR) * 30 + now.get(Calendar.MINUTE) / 12 * 6; // 先把分化为小时，再乘以6°
        /*
         * Calendar.HOUR 显示范围：1-12（无论AM还是PM） Calendar.HOUR_OF_DAY 显示范围：1-24（包括PM
         */

        Thread t = new Thread(this);
        t.start();
    }

    /*
     * 画图函数 注意：Applet的画图界面以左上角为(0,0)原点坐标，即所有坐标均大于等于0，该点的坐标越大（且>0）
     */
    public void paint(Graphics g) {
        super.paint(g);
        /*
         * paint(g)函数会重绘图像，要加上super.paint(g)，表示在原来图像的基础上，再画图。
         * 如果不加super.paint(g)，重绘时，会将原有的绘制清空，再根据paing(g)函数绘制。
         */

        g.setColor(Color.BLACK);
        g.drawOval(x, y, r * 2, r * 2);// 画表
        /* drawOval(x,y,width,height)以矩形恰好框住椭圆，矩形左上角的顶点坐标为(x,y) */

        // 秒针
        int x1 = (int) (90 * Math.sin(rad * s));
        int y1 = (int) (90 * Math.cos(rad * s));
        g.drawLine(r, r, r + x1, r - y1);
        /* drawLine(a,b,c,d) (a,b)为起始坐标 (c,d)为终点坐标 */

        // 分针
        x1 = (int) (80 * Math.sin(rad * m));
        y1 = (int) (80 * Math.cos(rad * m));
        g.drawLine(r, r, r + x1, r - y1);

        // 时针
        x1 = (int) (60 * Math.sin(rad * h));
        y1 = (int) (60 * Math.cos(rad * h));
        g.drawLine(r, r, r + x1, r - y1);

        // 画数字
        int d = 30;
        for (int i = 1; i <= 12; i++) {
            x1 = (int) ((r - 10) * Math.sin(rad * d));
            y1 = (int) ((r - 10) * Math.cos(rad * d));
            g.drawString(i + "", r + x1, r - y1);
            d += 30;
        }

        // 画刻度
        d = 0;
        for (int i = 1; i <= 60; i++) {
            x1 = (int) ((r - 2) * Math.sin(rad * d));
            y1 = (int) ((r - 2) * Math.cos(rad * d));
            g.drawString(".", r + x1, r - y1);
            d += 6;
        }
        // 显示时间
        Calendar now1 = new GregorianCalendar();
        int a, b, c;
        a = now1.get(Calendar.HOUR_OF_DAY);
        b = now1.get(Calendar.MINUTE);
        c = now1.get(Calendar.SECOND);
        g.drawString(a + ":" + b + ":" + c, 0, 10);

    }

    // 实现Runnable
    public void run() {
        while (true) {

            try {

                Thread.sleep(1000);// 间隔一秒

            } catch (Exception ex) {
            }

            // 秒针每次走6°
            s += 6;

            // 秒针归零
            if (s >= 360) {

                s = 0;
                m += 6;

                // 分针走72°，时针走6° 分针的12倍，时针走一次
                if (m == 72 || m == 144 || m == 288) {
                    h += 6;
                }

                // 分针归零
                if (m >= 360) {
                    m = 0;
                    h += 6;
                }

                // 时针归零
                if (h >= 360) {
                    h = 0;

                }
            }

            // 重新绘制
            this.repaint();
        }
    }

}

无注释简码：

package clockApplet;

import java.applet.Applet;
import java.awt.Color;
import java.awt.Graphics;
import java.util.Calendar;
import java.util.GregorianCalendar;

public class Test extends Applet implements Runnable {

    int x = 0,y = 0,r = 100,r1 = 90,r2 = 80,r3 = 60;
    double rad = Math.PI/180;
    int s,m,h;

    public void init(){
        Calendar calendar = new GregorianCalendar();
        s = calendar.get(Calendar.SECOND)*6;
        m = calendar.get(Calendar.MINUTE)*6;
        h = calendar.get(Calendar.HOUR)*30 + calendar.get(Calendar.MINUTE)/12*6;
        Thread thread = new Thread(this);
        thread.start();
    }

    public void paint(Graphics g) {
        super.paint(g);

        g.setColor(Color.black);
        g.drawOval(x, y, r*2, r*2);

        int x1 = (int)(r1*Math.sin(rad*s));
        int y1 = (int)(r1*Math.cos(rad*s));
        g.drawLine(r, r, r+x1, r-y1);

        x1 = (int)(r2*Math.sin(rad*m));
        y1 = (int)(r2*Math.cos(rad*m));
        g.drawLine(r, r, r+x1, r-y1);

        x1 = (int)(r3*Math.sin(rad*h));
        y1 = (int)(r3*Math.cos(rad*h));
        g.drawLine(r, r, r+x1, r-y1);

        int i,d = 0;
        for(i = 1;i <= 60;i++){
            x1 = (int)((r-2)*Math.sin(rad*d));
            y1 = (int)((r-2)*Math.cos(rad*d));
            g.drawString(".", r+x1, r-y1);
            d += 6;
        }
//
//        d = 30;
//        for(i = 1;i <= 12;i++){
//            x1 = (int)((r-10)*Math.sin(rad*d));
//            y1 = (int)((r-10)*Math.cos(rad*d));
//            g.drawString(i+"", r+x1, r-y1);
//            d+=30;
//        }

        Calendar now1 = new GregorianCalendar();
        int a, b, c;
        a = now1.get(Calendar.HOUR_OF_DAY);
        b = now1.get(Calendar.MINUTE);
        c = now1.get(Calendar.SECOND);
        g.drawString(a + ":" + b + ":" + c, 0, 10);

    }

    public void run() {
        while (true) {
            try {
                Thread.sleep(1000);
            } catch (Exception e) {
                System.err.println("出错");
            }

            s += 6;
            if (s >= 360) {
                s = 0;
                m += 6;

                if(m == 72||m == 144||m == 288){
                    h+=6;
                }

                if (m >= 360) {
                    m = 0;
                    h += 6;
                }

                if(h>=360){
                    h = 0;
                }
            }
            this.repaint();
        }

    }

}

简码实验结果：