JAVA范例 - Applet小应用程序

Applet小应用程序

实例337 不断变大的文字

　

import java.applet.Applet;
import java.awt.Color;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Image;

public class WordsToLarge extends Applet implements Runnable {
    private Image myImage;// 定义图片对象
    private Graphics myGraphic;// 定义Graphics对象
    private Font font;// 定义Font对象
    private String myString;// 定义一个字符串对象
    private Thread mythread;// 定义一个Thread对象
    private int fontSize;// 定义一个int型变量
    public void init() {// Applet小程序初始化
        this.setSize(400, 400);
        myImage = createImage(400, 400); // /创建Image图像对像
        myGraphic = myImage.getGraphics();
        myString = "Applet Java小程序";// 需要变化的文本内容
        font = new Font("TimesRoman", Font.BOLD, 8);
    }
    public void start() {// 启动多线程
        if (mythread == null) {
            mythread = new Thread(this);
            mythread.start();// 启动线程
        }
    }
    public void update(Graphics g) {// 重新调用paint方法
        paint(g);
    }
    public void paint(Graphics g) {// 绘图像
        myGraphic.setColor(Color.black);
        myGraphic.fillRect(0, 0, getSize().width, getSize().height);
        font = new Font("TimesRoman", Font.BOLD, fontSize);
        myGraphic.setFont(font);
        myGraphic.setColor(Color.white);
        FontMetrics fm = myGraphic.getFontMetrics(font);
        int fontHeight = fm.getHeight();
        int w;
        int baseLine = getSize().height / 2 + fontHeight / 2;
        w = fm.stringWidth(myString);
        w = (getSize().width - w) / 2;
        myGraphic.drawString(myString, w, baseLine -= 20);
        g.drawImage(myImage, 0, 0, this);
        fontSize++;
    }
    public void run() {// 重写Thread类的run方法
        while (true) {
            repaint();
            if (fontSize > getSize().height)
                fontSize = 0;
            try {
                mythread.sleep(100);
            } catch (InterruptedException e) {
            }
        }
    }
}

实例338 灯光扫描的效果 

import java.applet.Applet;
import java.awt.Color;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;

public class LightScan extends Applet implements Runnable {
    private String myText;// 声明文本对象
    private Font font;// 声明字体对象
    private int fontSize;// 声明字体的大小
    private Thread mythread;// 声明线程对象
    private int spotPosition = 100;// 声明光标点出现的位置
    private int myTextSize = 20;// 文本的大小
    private int myTextWidth = 0;// 文本的宽度
    private int fontHeight, baseLine, w;
    public void init()// 小程充的初始化
    {
        myText = "Applet小程序";// 在小程序中需要显示的文本对像
        fontSize = 30;// 设置字体的大小
        font = new Font("TimesRoman", Font.BOLD, fontSize); // 创建Font对像
        FontMetrics fm = getFontMetrics(font);// 获取FontMetrics字体规格对象。
        fontHeight = fm.getHeight();
        baseLine = getSize().height / 2 + fontHeight / 3;
        myTextWidth = fm.stringWidth(myText);
        w = fm.stringWidth(myText);
        w = (getSize().width - w) / 2;
        spotPosition = w;
        setBackground(Color.black); // 设置小程序的背景色为黑色
    }
    public void start() {
        if (mythread == null) {
            mythread = new Thread(this);// 创建多线程
            mythread.start();// 启动多线程
        }
    }
    public void stop() {
        mythread.stop();// 停止运行线程
        mythread = null;
    }
    public void run()// 运行线程
    {
        while (true) {
            repaint();// 重绘此组件
            try {
                mythread.sleep(30);
            }// 线程休眠
            catch (InterruptedException e) {
            }
        }
    }
    public void update(Graphics g)// 更新组件
    {
        paint(g);
    }
    // 利用clipRect()方法，每次调用显示方法paint()时，
    // 先用红色的笔画一遍文字，再用白色在裁剪区中画一遍文字
    public void paint(Graphics g) {
        g.setFont(font);
        g.setColor(Color.red);
        g.drawString(myText, w, baseLine); // 第一遍显示
        g.clipRect(spotPosition, 0, myTextSize, getSize().height); // 设置裁剪区域
        g.setColor(Color.white);
        g.drawString(myText, w, baseLine); // 第二遍显示
        spotPosition = (spotPosition + 1) % (myTextWidth + 100); // 移动光标位置
    }
}

实例339 字体逐渐展开的效果 

import java.applet.Applet;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Image;

public class WordsToExpand extends Applet implements Runnable {
    private Image myImage;//声明Image图象对象
    private Graphics myGraphic;//声明Graphics对象
    private int width = 0, height = 0;//声明高和宽变量
    private String words;//定义文本内容
    private Thread mythread;//声明Thread多线程对象
    private int xPosition = 0, yPosition = 0, myHeight;//定义x和y坐标点
    private int times = 0;//表示线条出现的方向
    private Font font;
    public void init()//初始化Applet小程序
    {
        this.setSize(300, 200);
        font = new Font("TimesRoman", Font.BOLD, 30);
        width = 300;
        height = 200;
        myHeight = height / 3;
        yPosition = myHeight;
        words = "大家好";
        myImage = createImage(width, height);
        myGraphic = myImage.getGraphics();
    }
    public void start()//起动Applet小程序和多线程
    {
        if (mythread == null) {
            mythread = new Thread(this);
            mythread.start();
        }
    }
    public void update(Graphics g)//更新组件
    {
        paint(g);
    }
    public void paint(Graphics g)//绘制组件
    {
        g.drawImage(myImage, 0, yPosition, width, myHeight, this);
    }
    public void run()//运行多线程
    {
        try {
            while (true) {
                yPosition = 0;
                myHeight = height;
                myGraphic.setColor(Color.pink);
                myGraphic.fillRect(0, 0, width, height);
                repaint();
                mythread.sleep(100);
                if (times == 0) {
                    myGraphic.setColor(Color.black);
                    for (int i = width; i >= 0; i--) {
                        myGraphic.fillRect(i, height / 3, width, height / 10);
                        repaint();
                        mythread.sleep(10);
                    }
                } else if (times == 1) {
                    myGraphic.setColor(Color.blue);
                    for (int i = 0; i <= width; i++) {
                        myGraphic.fillRect(0, height / 3, i, height / 10);
                        repaint();
                        mythread.sleep(10);
                    }
                }
                yPosition = height / 3;
                myHeight = height / 3;
                for (int i = height / 3; i >= 0; i--) {
                    xPosition = 0;
                    yPosition--;
                    myHeight = myHeight + 2;
                    if (times == 0)//0表示从右向左移动
                    {
                        myGraphic.setColor(Color.black);
                        myGraphic.fillRect(0, 0, width, height);
                        myGraphic.setFont(font);
                        myGraphic.setColor(Color.yellow);
                        myGraphic.drawString(words, 10, 35);
                        times++;
                    } else if (times == 1)//1表示从左向右移动
                    {
                        myGraphic.setColor(Color.red);
                        myGraphic.fillRect(0, 0, width, height);
                        myGraphic.setFont(font);
                        myGraphic.setColor(Color.black);
                        myGraphic.drawString(words, 10, 35);
                        times = 0;
                    }
                    repaint();
                    mythread.sleep(100);
                }
                mythread.sleep(2500);
                System.out.println(times);
            }
        } catch (InterruptedException e) {
        }
    }
}

实例340 飞舞的气球 

import java.applet.Applet;
import java.awt.Color;
import java.awt.Graphics;

public class FlyBall extends Applet implements Runnable {
    Thread artist = null;
    int bubble = 0, thisbubble = 0; // 气球数量，当前气球编号
    int MAXBUBBLES = 25; // 最大气球数量
    int stepper = 4; // Counter for which bubbles to move when
    int record[][] = new int[MAXBUBBLES][5]; // 记录气球的二维数组
    public void init() {        // 初始化applet
        resize(400, 400);     // 设定applet尺寸
    }
    public void draw_bubble(int x, int y, int r, Color col, Graphics g) {
        // 输出气球
        int i;
        // 输出一个圆形
        for (i = x - r; i <= x + r; i++) {
            g.setColor(col);
            g.drawLine(i, y - (int) (Math.sqrt(r * r - ((i - x) * (i - x)))),
                    i, y + (int) (Math.sqrt(r * r - ((i - x) * (i - x)))));
        }
    }
    public void move_bubble(int x, int y, int r, Color col, int step, Graphics g) {
        // 移动气球
        int i;
        // 输出气球的上半部分
        for (i = x - r; i <= x + r; i++) {
            g.setColor(col);
            g.drawLine(i, y - (int) (Math.sqrt(r * r - ((i - x) * (i - x)))),
                    i, y + step
                            - (int) (Math.sqrt(r * r - ((i - x) * (i - x)))));
        }
        // 输出气球的下半部分
        for (i = x - r; i <= x + r; i++) {
            g.setColor(Color.white);
            g.drawLine(i, y + (int) (Math.sqrt(r * r - ((i - x) * (i - x)))),
                    i, y + step
                            + (int) (Math.sqrt(r * r - ((i - x) * (i - x)))));
        }
    }
    public void paint(Graphics g) {
        int i, j, tmp;
        if (bubble < MAXBUBBLES || thisbubble < MAXBUBBLES) {
            record[thisbubble][0] = (int) (Math.random() * 300);
            record[thisbubble][1] = 320;
            record[thisbubble][2] = (int) (Math.random() * 400) / 20;
            record[thisbubble][3] = (int) (Math.random() * 255);
            record[thisbubble][4] = (int) (Math.random() * 255);
            // 输出气球
            draw_bubble(record[thisbubble][0], record[thisbubble][1],
                    record[thisbubble][2], new java.awt.Color(
                            record[thisbubble][3], record[thisbubble][4], 255),
                    g);
            // 如气球数小于最大值，则总气球数自增1，当前气球编号自增1
            if (bubble < MAXBUBBLES) {
                bubble++;
                thisbubble++;
            } else
                // 气球数等于最大值
                thisbubble = MAXBUBBLES;
        }
        for (i = 0; i < bubble; i++) {
            if (i % 5 <= stepper) {
                record[i][1] -= 1;
                // 移动气球
                move_bubble(record[i][0], record[i][1], record[i][2],
                        new java.awt.Color(record[i][3], record[i][4], 255), 1,
                        g);
                for (j = 0; j < i; j++) {
                    tmp = ((record[i][1] - record[j][1])
                            * (record[i][1] - record[j][1]) + (record[i][0] - record[j][0])
                            * (record[i][0] - record[j][0]));
                    if (j != i && Math.sqrt(tmp) < record[i][2] + record[j][2]) {
                        for (tmp = record[i][2]; tmp >= -1; tmp = tmp - 2)
                            draw_bubble(record[i][0], record[i][1],
                                    record[i][2] - tmp, Color.white, g);
                        draw_bubble(record[j][0], record[j][1], record[j][2],
                                new java.awt.Color(record[j][3], record[j][4],
                                        255), g);
                        record[i][1] = -1;
                        record[i][2] = 0;
                    }
                }
            }
            if (record[i][1] + record[i][2] < 0 && bubble >= MAXBUBBLES) {
                thisbubble = i;
            }
            stepper = (int) (Math.random() * 10);
        }
    }
    public void update(Graphics g) {
        paint(g);
    }
    public void start() {
        // 启动applet,创建并启动线程
        if (artist == null) {
            artist = new Thread(this);
            artist.start();
        }
    }
    public void stop() {
        // 结束applet
        artist = null;
    }
    public void run() {
        // 启动线程
        while (artist != null) {
            try {
                Thread.sleep(200);
            } catch (InterruptedException e) {
            }
            repaint();
        }
        artist = null;
    }
}

实例341 逐渐浮现的图片 

import java.applet.Applet;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.MediaTracker;
import java.awt.Point;
import java.awt.image.PixelGrabber;
import java.util.Random;

public class FloatsPicture extends Applet {
    private Image image;// 声明图片对象
    private int x = 25, y = 25;// 定义int型变量 分别表示x和y坐标点的值
    private Random random;// 声明随机数类Random对象
    private int width, height, w, h, image_size, pixels[];// 定义int型变量和数组
    public void init() { // 初始化applet
        this.setSize(400, 400);
        random = new Random();
        // 从网页获取图片文件名参数
        String imageName = "7.jpg";
        // 加载图片
        image = getImage(getDocumentBase(), imageName);
        MediaTracker imageTracker = new MediaTracker(this);
        imageTracker.addImage(image, 0);
        try {
            imageTracker.waitForID(0);
        } catch (InterruptedException e) {
        }
    }
    public void start() {
        // 启动applet,然后调用paint()方法
        width = getSize().width; // applet宽度
        height = getSize().height; // applet高度
        w = image.getWidth(this); // 图片宽度
        h = image.getHeight(this); // 图片高度
        // 图片输出位置
        x = (width - w) / 2;
        y = (height - h) / 2;
        // 图片大小
        image_size = w * h;
        // 创建图片的像素数组
        pixels = new int[image_size];
        // 创建一个像素获取器的实例，并将其与像素数组关联
        PixelGrabber pg = new PixelGrabber(image, 0, 0, w, h, pixels, 0, w);
        try {
            // 解析图片的像素信息
            pg.grabPixels();
        } catch (InterruptedException e) {
        }
    }
    public void paint(Graphics g) {
        g.setColor(Color.white);
        g.fillRect(0, 0, getSize().width, getSize().height);
        // 调用drawImage()方法，在相应的位置输出图片
        drawImage(g, image, x, y);
    }
    private void drawImage(Graphics g, Image image, int x, int y) {
        // 输出图片
        while (true) {
            g.setColor(Color.white);
            g.fillRect(0, 0, getSize().width, getSize().height);
            try {
                int one_time = w; // 图片宽度
                int S_x = 0, S_y = 0;
                S_x = (int) (random.nextFloat() * width);
                S_y = (int) (random.nextFloat() * height);
                Laser[] nextlot = new Laser[one_time];
                int k = 0, l = 0;
                int step = 1, start = 0;
                float f = random.nextFloat();
                step = (f < 0.8) ? 34759 : (f < 0.9 ? 1 : image_size - 1); // 步长
                // start=(int)(random.nextFloat()*image_size); //起始位置
                f = random.nextFloat();
                start = (f < 0.5) ? image_size : 0; // 如果f小于0.5,则起始位置为图片大小，否则为0
                int sofar = 0;
                // 初始化nextlot数组
                for (k = start; l < image_size; l++, k += step) {
                    Thread.sleep(2);
                    if (k < 0)
                        k += image_size;
                    k %= image_size;
                    int row = k / w;
                    int col = k % w;
                    Color colr = new Color(pixels[k]);
                    int finishx = x + col;
                    int y1 = y + row;
                    nextlot[sofar] = new Laser(colr, new Point(S_x, S_y),
                            new Point(finishx, y1));
                    sofar++;
                    if (sofar == one_time) {
                        Track(g, nextlot);
                        sofar = 0;
                    }
                }
            } catch (Exception e) {
            }
            g.setPaintMode();
            g.drawImage(image, x, y, this);
            try {
                Thread.sleep(10);
            } catch (InterruptedException e) {
            }
        }
    }
    private synchronized void Track(Graphics g, Laser[] nextlot) {
        Color back = Color.white;
        g.setXORMode(back);
        for (int pass = 0; pass < 2; pass++) {
            for (int pixnr = 0; pixnr < nextlot.length; pixnr++) {
                Laser p = nextlot[pixnr];
                if (!close(p.c, back)) {
                    g.setColor(p.c);
                    g.drawLine(p.start.x, p.start.y, p.finish.x, p.finish.y);
                }
                if (pass == 1) {
                    g.setColor(p.c);
                    g.drawLine(p.finish.x, p.finish.y, p.finish.x, p.finish.y);
                }
            }
        }
        Thread.yield();
    }
    private boolean close(Color c1, Color c2) {
        return (Math.abs(c1.getRed() - c2.getRed())
                + Math.abs(c1.getGreen() - c2.getGreen()) + Math.abs(c1
                .getBlue()
                - c2.getBlue())) < 0xff;
    }
}
class Laser {
    public Color c;
    public Point start, finish;
    public Laser(Color c, Point start, Point finish) {
        this.c = c;
        this.start = start;
        this.finish = finish;
    }
}

实例342 火焰边框的特效

import java.applet.Applet;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.MediaTracker;

public class FireBorder extends Applet implements Runnable
// 在applet中支持线程，需要实现Runnable接口
{
    private Image bimg, fimg, offI, virtualI;// 声明Image图象对象
    private Graphics offG, virtualG;// 声明Graphics对象
    private Thread thread = null;// 声明Thread多线程对象
    private MediaTracker imageTracker;// 声明MediaTracker对象
    private int height, width, X, Y;// 声明int型变量
    public void init() {
        // 初始化applet,加载背景图片、前景图片
        this.setSize(300, 200);
        String imageName = "01.jpg";
        String imageName2 = "5.gif";
        bimg = getImage(getDocumentBase(), imageName);// 获取背景图片
        fimg = getImage(getDocumentBase(), imageName2);// 获取前景图片
        imageTracker = new MediaTracker(this); // 创建一个媒体跟踪器的实例
        // 将图片加入到 MedialTracker 的监视队列中去， image 为要被监视的图像对象，
        // 0 为监视图像在监视队列中的标识号
        imageTracker.addImage(bimg, 0);
        imageTracker.addImage(fimg, 0);
        width = this.getSize().width; // 设置applet宽度
        height = this.getSize().height; // 设置applet高度
        try {
            imageTracker.waitForID(0); // 加载图片
        } catch (InterruptedException e) {
        }
        offI = createImage(width, height);
        offG = offI.getGraphics();
        virtualI = createImage(width * 2, height * 2);
        virtualG = virtualI.getGraphics();
    }
    public void start() {
        // 启动applet,创建并启动一个线程
        if (thread == null) {
            thread = new Thread(this); // 以applet初始化线程
            thread.start(); // 启动线程，调用run()方法
        }
    }
    public void run() {
        // 线程调用开始
        int x = 0, y = 0;
        int tileWidth = bimg.getWidth(this); // 设置招牌宽度
        int tileHeight = bimg.getHeight(this); // 设置招牌高度
        while (thread != null) {
            try {
                Thread.sleep(10);
                x = virtualI.getWidth(this) - width;
                y = virtualI.getHeight(this) - height;
                // 在不同的坐标位置输出图像以产生燃烧效果
                for (; (x > 0) && (y > 0); x--, y--) {
                    if ((x == 0) || (y == 0)) {
                        x = virtualI.getWidth(this) - width;
                        y = virtualI.getHeight(this) - height;
                    }
                    // 输出图像，产生燃烧特效
                    for (int j = 0; j < virtualI.getHeight(this); j = j
                            + tileHeight)
                        for (int i = 0; i < virtualI.getWidth(this); i = i
                                + tileWidth)
                            virtualG.drawImage(bimg, i, j, this);
                    virtualG.drawImage(fimg, x, y, width, height, this);
                    offG.drawImage(virtualI, -x, -y, this);
                    // 输出applet，调用update()方法
                    repaint();
                }
            } catch (InterruptedException e) {
            }
        }
    }
    public void update(Graphics g) {
        // 调用paint()方法
        paint(g);
    }
    public void paint(Graphics g) {
        // 输出applet
        g.drawImage(offI, 0, 0, this);
    }
}

实例343 局部放大效果 　

import java.applet.Applet;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.MediaTracker;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;

public class ZoomWords extends Applet implements MouseMotionListener {
    Graphics g;// 声明Graphics对象
    Image image;// 声明Image对象
    Image back_Image;// 声明Image对象
    String name;// 声明String对象
    MediaTracker tracker; // 声明媒体跟踪器tracker
    int Glass_X = 0, Glass_Y = 0; // 放大镜初始位置
    int Glass_W = 100, Glass_H = 100; // 放大镜宽度、高度
    int width, height; // 声明背景图片的宽度和高度
    public void init() { // 初始化applet
        // 加载图片
        this.setSize(370, 500);
        g = getGraphics();
        name = "01.jpg";
        tracker = new MediaTracker(this);
        back_Image = getImage(getDocumentBase(), name);
        image = createImage(250, 100); // 设置放大后的图象的大小
        Graphics offg = image.getGraphics();
        offg.drawImage(back_Image, 0, 0, this);
        addMouseMotionListener(this); // 添加鼠标事件侦听
    }
    public void mouseDragged(MouseEvent e) { // 鼠标拖拽事件处理
    }
    public void mouseMoved(MouseEvent e) { // 处理鼠标移动事件
        reprintGlass(Glass_X, Glass_Y, e.getX(), e.getY()); // 通过鼠标位置设置放大镜的位置
        // 设置放大镜的当前位置
        Glass_X = e.getX();
        Glass_Y = e.getY();
        // 若放大镜溢出applet则进行调整
        if (Glass_X > (width - Glass_W / 2))
            Glass_X = width - Glass_W / 2;
        if (Glass_Y > (height - Glass_H / 2))
            Glass_Y = height - Glass_H / 2;
        printGlass(); // 调用自定义方法—输出放大镜
    }
    void printGlass() {
        Graphics temp = g.create(); // 复制g的一个实例
        temp.clipRect(Glass_X, Glass_Y, Glass_W, Glass_H); // 为temp限制一个矩形区域
        temp.drawImage(back_Image, -Glass_X, -Glass_Y, width * 2, height * 2,
                null); // 输出放大后的图象
        g.setColor(Color.black);// 设置放大镜边框的颜色
        g.drawRect(Glass_X, Glass_Y, Glass_W - 1, Glass_H - 1);// 输出放大镜边框
    }
    void reprintGlass(int X, int Y, int new_X, int new_Y) { // 清除已经画过的矩形框和放大的图象
        Graphics temp = g.create(); // 同上
        if (new_X <= X && new_Y <= Y) {
            temp.clipRect(new_X, new_Y + Glass_H, Glass_W + X - new_X, Y
                    - new_Y);
            temp.drawImage(image, 0, 0, null);
            temp = g.create();
            temp.clipRect(new_X + Glass_W, new_Y, X - new_X, Glass_H + Y
                    - new_Y);
            temp.drawImage(image, 0, 0, null);
        } else if (new_X > X && new_Y <= Y) {
            temp.clipRect(X, new_Y + Glass_H, Glass_W + new_X - X, Y - new_Y);
            temp.drawImage(image, 0, 0, null);
            temp = g.create();
            temp.clipRect(X, new_Y, new_X - X, Glass_H + Y - new_Y);
            temp.drawImage(image, 0, 0, null);
        } else if (new_X > X && new_Y > Y) {
            temp.clipRect(X, Y, Glass_W + new_X - X, new_Y - Y);
            temp.drawImage(image, 0, 0, null);
            temp = g.create();
            temp.clipRect(X, Y, new_X - X, Glass_H + new_Y - Y);
            temp.drawImage(image, 0, 0, null);
        } else {
            temp.clipRect(new_X, Y, Glass_W + X - new_X, new_Y - Y);
            temp.drawImage(image, 0, 0, null);
            temp = g.create();
            temp.clipRect(new_X + Glass_W, Y, X - new_X, Glass_H + new_Y - Y);
            temp.drawImage(image, 0, 0, null);
        }
    }
    public boolean imageUpdate(Image img, int infoflags, int x, int y, int w,
            int h) { // 判断infoflags参数是否已完全加载了图像，是则返回false；否则返回true
        if (infoflags == ALLBITS) { // ALLBITS指示现在已完成了一幅以前绘制的静态图像，并且可以其最终形式再次绘制它。
            width = back_Image.getWidth(this);
            height = back_Image.getHeight(this);
            image = createImage(width + Glass_W / 2, height + Glass_H / 2);
            Graphics offg = image.getGraphics();
            offg.setColor(Color.white);
            offg.fillRect(0, 0, width + Glass_W / 2, height + Glass_H / 2);
            offg.drawImage(back_Image, 0, 0, this);
            repaint();
            return false;
        } else
            return true;
    }
    public void paint(Graphics g) {
        g.drawImage(back_Image, 0, 0, this); // 输出背景图片
        printGlass(); // 画放大镜
    }
}

实例344 水波荡漾的效果 

import java.applet.Applet;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.MediaTracker;
public class Reflection extends Applet implements Runnable {
    Thread thread = null;                    // 声明线程
    private Graphics g, inv_g;                // 定义绘制正常图像和倒立后图像的Graphics对象
    private Image image, invimage;            // image用于载入正常图像，invimage用于载入倒立后图像
    private int inv;                        // 应用于形成倒立影象的变量
    private int image_W = 2, image_H = 2;    // 定义装载图片宽和高的变量
    private boolean load_Flag = false;        // 定义标志，其作用是标志加载图片是否完毕
    private final int fre = 14;                // 定义水纹波动的频率，数值越大，波动越慢。
    private String picture_name = "";        // 定义图片名字
    public void init() {                    // 初始化applet
        picture_name = "5.jpg";
    }
    public void paint(Graphics g) {
        if (!load_Flag)                    // 如果已经载入图片，则返回
            return;
        if (invimage != null) {                // 输出倒影图片
            g.drawImage(invimage, (-inv * image_W), image_H, this);
            g.drawImage(invimage, ((fre - inv) * image_W), image_H, this);
        }
        g.drawImage(image, 0, -1, this);    // 输出正向图片
    }
    public void start() {                    // 启动applet，创建并启动线程
        if (thread == null) {
            thread = new Thread(this);
            thread.start();
        }
    }
    public void run() {// 启动线程
// 加载图片
inv = 0;
g = getGraphics();
MediaTracker imageTracker = new MediaTracker(this);
image = getImage(this.getCodeBase(), picture_name);
imageTracker.addImage(image, 0);
try {
            imageTracker.waitForAll();
            load_Flag = !imageTracker.isErrorAny();    // 检查媒体跟踪器跟踪的所有图像的错误状态
        } catch (InterruptedException e) {
        }
                                            // 图片宽度、图片高度
        image_W = image.getWidth(this);
        image_H = image.getHeight(this);
        this.setSize(image_W+1, image_H * 2 - 19);
        creatWater();                            // 生成倒影
        repaint();                                // 重新输出applet
        while (true) {
            try {
                if (!load_Flag)
                    return;
                if (invimage != null) {
                    g.drawImage(invimage, (-inv * image_W), image_H, this);
                    g.drawImage(invimage, ((fre - inv) * image_W), image_H,
                            this);
                }
                g.drawImage(image, 0, -1, this);
                if (++inv == fre)
                    inv = 0;
                Thread.sleep(50);
            } catch (InterruptedException e) {
                stop();
            }
        }
    }
    public void creatWater() {                        //产生水波特效
        Image back = createImage(image_W+3, image_H + 2);
        Graphics graphics = back.getGraphics();
        int phase = 0;
        int x, y;
        double p1;
        graphics.drawImage(image, 0, 1, this);
        for (int i = 0; i < (image_H >> 1); i++) {
            graphics.copyArea(0, i, image_W, 1, 0, image_H - i);
            graphics.copyArea(0, image_H - 1 - i, image_W, 1, 0, -image_H + 1
                    + (i << 1));
            graphics.copyArea(0, image_H, image_W, 1, 0, -1 - i);
        }
        invimage = createImage((fre + 1) * image_W+20, image_H+2);
        inv_g = invimage.getGraphics();
        inv_g.drawImage(back, fre * image_W, 0, this);
        for (phase = 0; phase < fre; phase++) {
            p1 = 2 * Math.PI * (double) phase / (double) fre;
            x = (fre - phase) * image_W;
            for (int i = 0; i < image_H; i++) {
                y = (int) ((image_H / 14)
                        * ((double) i + 28.0)
                        * Math.sin((double) ((image_H / 14) * (image_H - i))
                                / (double) (i + 1) + p1) / (double) image_H);
                if (i < -y)
                    inv_g.copyArea(fre * image_W, i, image_W, 1, -x, 0);
                else
                    inv_g.copyArea(fre * image_W, i + y, image_W, 1, -x,
                            -y);
            }
        }
graphics.drawImage(image, 0, 1, this);
image = back;
    }
}

实例345 漫天飞花 　　

import java.applet.Applet;
import java.awt.Color;
import java.awt.Graphics;
import java.net.URL;
import java.util.Random;
public class MissileDemo extends Applet implements Runnable {
public int speed, variability, Max_Number, Max_Energy, Max_Patch,
            Max_Length, G;
    public String sound;
    private int width, height;                    // 获取当前容器边界的宽和高
    private Thread thread = null;                // 设置线程
    private BeaClassDemo bcd[];                // 创建BeaClassDemo类数组bcd
    public void init() {                        // Applet初始化
        int i;
        this.setSize(400, 400);                 // 设置当前容器的宽和高
        width = getSize().width - 1;
        height = getSize().height - 1;
        speed = 30;                        // 烟花绽放的速度
        variability = 10;
        Max_Number = 100;                    // 可发出烟花的最大数目
        Max_Energy = width + 50;
        Max_Patch = 80;                    // 最大的斑点数
        Max_Length = 200;                    // 斑点的最大距离
        G = 50;                            // 向地面弯曲的力度
        bcd = new BeaClassDemo[Max_Number];            // 初始化BeaClassDemo数组
        for (i = 0; i < Max_Number; i++)
            bcd[i] = new BeaClassDemo(width, height, G);    // 创建BeaClassDemo类对象
    }
    public void start() {        // 启动线程
        if (thread == null) {
            thread = new Thread(this);
            thread.start();
        }
    }
    public void stop() {        // 停止线程
        if (thread != null) {
            thread.stop();
            thread = null;
        }
    }
    public void run() {
        int i;
        int E = (int) (Math.random() * Max_Energy * 3 / 4) + Max_Energy / 4 + 1;
        int P = (int) (Math.random() * Max_Patch * 3 / 4)    // 烟花的斑点数
                + Max_Patch / 4 + 1;
        int L = (int) (Math.random() * Max_Length * 3 / 4)    // 烟花可发射出的距离
                + Max_Length / 4 + 1;
        long S = (long) (Math.random() * 10000);            // 产生的随机数
        boolean sleep;                                // 体眠的标志
        Graphics g = getGraphics();
        URL u = null;
        while (true) {
            try {
                thread.sleep(1000 / speed);
            } catch (InterruptedException x) {
            }
            sleep = true;
            for (i = 0; i < Max_Number; i++)
                sleep = sleep && bcd[i].sleep;
            if (sleep && Math.random() * 100 < variability) {
                E = (int) (Math.random() * Max_Energy * 3 / 4) + Max_Energy / 4
                        + 1;
P = (int) (Math.random() * Max_Patch * 3 / 4) + Max_Patch / 4
                        + 1;
L = (int) (Math.random() * Max_Length * 3 / 4) + Max_Length / 4
                        + 1;
                S = (long) (Math.random() * 10000);
            }
            for (i = 0; i < Max_Number; i++) {
                if (bcd[i].sleep && Math.random() * Max_Number * L < 1) {
bcd[i].init(E, P, L, S);
bcd[i].start();
                }
                bcd[i].show(g);
            }
        }
    }
    public void paint(Graphics g) {                    // 绘制组件
        g.setColor(Color.black);                    // 设置背景颜色为黑
        g.fillRect(0, 0, width + 1, height + 1);            // 根据参数画矩形
    }
}
class BeaClassDemo {
public boolean sleep = true;
private int energy, patch, length, width, height, G, Xx, Xy, Ex[], Ey[], x,
            y, Red, Blue, Green, t;
    private Random random;                        // 声明Random类对象
    public BeaClassDemo(int a, int b, int g) {            // 类BeaClassDemo的构造方法
        width = a;
        height = b;
        G = g;
    }
    public void init(int e, int p, int l, long seed) {// 初始化
        int i;
    // 赋值运算
energy = e;
patch = p;
length = l;
        // 创建一个带种子的随机数生成器
        random = new Random(seed);
        Ex = new int[patch];                        // 初始化int数组Ex，其长度为patch
        Ey = new int[patch];                        // 初始化int数组Ey，其长度为patch
        // 随机生成不透明的sRGB颜色值
        Red = (int) (random.nextDouble() * 128) + 128;
        Blue = (int) (random.nextDouble() * 128) + 128;
        Green = (int) (random.nextDouble() * 128) + 128;
        Xx = (int) (Math.random() * width / 2) + width / 4;
        Xy = (int) (Math.random() * height / 2) + height / 4;
        for (i = 0; i < patch; i++) {
            Ex[i] = (int) (Math.random() * energy) - energy / 2;
            Ey[i] = (int) (Math.random() * energy * 7 / 8) - energy / 8;
        }
    }
    public void start() {
t = 0;
sleep = false;
    }
    public void show(Graphics g) {        // 输出烟花
        if (!sleep)                    // 如果休眠状态为false
            if (t < length) {
                int i, c;
                double s;
                Color color;
                c = (int) (random.nextDouble() * 64) - 32 + Red;
                if (c >= 0 && c < 256)
                    Red = c;
                c = (int) (random.nextDouble() * 64) - 32 + Blue;
                if (c >= 0 && c < 256)
                    Blue = c;
                c = (int) (random.nextDouble() * 64) - 32 + Green;
                if (c >= 0 && c < 256)
                    Green = c;
                color = new Color(Red, Blue, Green);
                for (i = 0; i < patch; i++) {
                    s = (double) t / 100;
                    x = (int) (Ex[i] * s);
                    y = (int) (Ey[i] * s - G * s * s);
                    g.setColor(color);
                    g.drawLine(Xx + x, Xy - y, Xx + x, Xy - y);
                    if (t >= length / 2) {
                        int j;
                        for (j = 0; j < 2; j++) {
                            s = (double) ((t - length / 2) * 2 + j) / 100;
                            x = (int) (Ex[i] * s);
                            y = (int) (Ey[i] * s - G * s * s);
                            g.setColor(Color.black);
                            g.drawLine(Xx + x, Xy - y, Xx + x, Xy - y);
                        }
                    }
                }
                t++;
            } else {
                sleep = true;
            }
    }
}

实例346 动感影集 　　

import java.applet.Applet;
import java.awt.Choice;
import java.awt.Event;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.MediaTracker;

public class PhotoAlbum extends Applet {
    private Choice myChoice;// 声明Choice对象
    private String[] myString1, myString2;// 声明String类型的数组
    private int totalPics;// 声明一个int型变量
    private Image offI;// 声明Image对象
    private Image[] img;// 声明一组Image对象数组
    private Graphics offG;// 声明一个Graphics对象
    private MediaTracker imagetracker;// 声明一个MediaTracker对象
    public void init() {// 对Applet小程序进行初始化
        this.setSize(600, 450);
        this.setLayout(null);
        myChoice = new Choice();
        myChoice.setBounds(10, 10, 290, 20);
        totalPics = 8;
        myString1 = new String[totalPics];
        myString2 = new String[totalPics];
        img = new Image[totalPics];
        for (int i = 0; i < totalPics; i++) {
            myString1[i] = new String("");
            myString2[i] = new String("");
        }
        String s = new String("");
        imagetracker = new MediaTracker(this);// 加载图片
        for (int i = 0; i < totalPics; i++) {
            s = "第 " + (i + 1) + " 张照片";
            myString1[i] = s;
            System.out.println(myString1[i]);
            myChoice.addItem(s);// 向下拉列表中增加选项
            s = (i + 1) + ".jpg";
            myString2[i] = s;
            img[i] = getImage(getDocumentBase(), s);
            imagetracker.addImage(img[i], 0);
        }
        try {
            imagetracker.waitForID(0);
        } catch (InterruptedException e) {
        }
        add(myChoice);
        offI = createImage(getSize().width, getSize().height - 40);// 创建图象
        offG = offI.getGraphics();
        offI = img[0];
        offG.drawImage(offI, 0, 0, this);
        repaint();
    }
    public void paint(Graphics g) {
        g.drawImage(offI, 10, 40, this);
    }
    // 使用action()方法来获得Java Applet小程序运行时所发生的事件
    public boolean action(Event e, Object o) {
        if (e.target == myChoice) {
            // String s = new String("");
            offG.setColor(this.getBackground());
            offG.fillRect(0, 40, getSize().width, getSize().height - 40);
            offI = img[myChoice.getSelectedIndex()];
            offG.drawImage(offI, 0, 0, this);
            repaint();
        }
        return true;
    }
}

实例347 彩虹字 　　

import java.applet.Applet;
import java.awt.Color;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Image;

public class RainbowWords extends Applet implements Runnable {
    String str = null;
    Thread thread = null; // 设置一个线程
    char[] ch;
    int p = 0;
    Image image;
    Graphics gphics;
    Color[] color;
    int one = 1;
    int two = 18;
    int three = 18;
    private Font f; // 字体
    private FontMetrics fm; // 字模
    public void init() {
        str = "Java Applet小程序"; // 设置七彩文字内容
        this.setSize(520, 200); // 设置Applet的大小
        setBackground(Color.white); // 设置背景颜色
        ch = new char[str.length()];
        ch = str.toCharArray(); // 将字符串中的各个字符保存到数组中
        image = createImage(getSize().width, getSize().height);
        gphics = image.getGraphics();
        f = new Font("", Font.BOLD, 18);
        fm = getFontMetrics(f); // 获得指定字体的字体规格
        gphics.setFont(f); // 设置组件的字体
        float hue;
        color = new Color[str.length()]; // 颜色的色元
        for (int i = 0; i < str.length(); i++) {
            hue = ((float) i) / ((float) str.length());
            color[i] = new Color(Color.HSBtoRGB(hue, 0.8f, 1.0f)); // 颜色分配
        }
    }
    public void start() { // 线程开始的类
        if (thread == null) { // 如果线程为空，则
            thread = new Thread(this);
            // 开始新的线程
            thread.start(); // 开始
        }
    }
    // 终止线程
    public void stop() {
        if (thread != null) { // 如果线程不为空，则
            thread.stop(); // 终止线程，使它
            thread = null; // 为空
        }
    }
    // 运行线程
    public void run() {
        while (thread != null) {
            try {
                thread.sleep(200); // 让线程沉睡200毫秒
            } catch (InterruptedException e) {
            }
            repaint(); // 重新绘制界面
        }
    }
    public void update(Graphics g) { // 重写update方法，解决闪烁问题
        int x, y;
        double a;
        gphics.setColor(Color.black);
        gphics.fillRect(0, 0, getSize().width, getSize().height);
        p += one;
        p %= 7; // 主要控制字的速度，被除数越小，速度越快
        // System.out.println(p+” p1”);
        for (int i = 0; i < str.length(); i++) {
            a = ((p - i * one) % 7) / 4.0 * Math.PI; // 主要控制弧度的，被除数越小，弧度越大
            x = 30 + fm.getMaxAdvance() * i + (int) (Math.cos(a) * two); // 求x坐标值
            y = 80 + (int) (Math.sin(a) * three); // 求y坐标值
            gphics.setColor(color[(p + i) % str.length()]);
            gphics.drawChars(ch, i, 1, x, y);
        }
        paint(g);
    }
    public void paint(Graphics g) {
        g.drawImage(image, 0, 0, this);
    }
}

实例348 多功能按键 

import java.applet.Applet;
import java.applet.AudioClip;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Label;
import java.awt.MediaTracker;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

public class StrongButton extends Applet implements MouseListener {
    private Graphics grap; // 声明Graphics变量
    private MediaTracker media; // 声明MediaTracker变量
    private AudioClip audioA, audioB; // 声明AudioClip变量
    private int width, height; // 声明int类变量
    private Image image, img1, img2, img3; // 声明Image类型变量
    private Label la = new Label("多功能按键"); // 创建一个带初始值的Label对象
    public void init() { // 为Applet初始化
        audioA = getAudioClip(this.getDocumentBase(), "aa.wav"); // 创建audioA对象
        audioB = getAudioClip(getDocumentBase(), "hh.wav"); // //创建audioB对象
        width = getSize().width; // 返回Applet的宽度
        height = getSize().height; // 返回Applet的高度
        image = createImage(width, height); // 根据参数创建一个Image对象
        grap = image.getGraphics(); // 根据图像创建Graphics对像
        media = new MediaTracker(this); // MediaTracker对像实例化
        img1 = getImage(getDocumentBase(), "2.jpg"); // 根据参数创建Image对象
        media.addImage(img1, 0); // 将img1放入media对象中
        img2 = getImage(getDocumentBase(), "3.jpg");
        media.addImage(img2, 1);
        img3 = getImage(getDocumentBase(), "4.jpg");
        media.addImage(img3, 2);
        try {
            media.waitForAll(); // 等待media加载所有的图像
        } catch (InterruptedException e) {
        }
        la.setSize(100, 20);
        la.setForeground(Color.blue); // 设置标签的前景颜色
        this.add(la, BorderLayout.NORTH); // 将标签组件加载到Applet中
        addMouseListener(this); // 为Applet添加鼠标侦听事件
    }
    public void start() { // 开始Applet程序
        grap.drawImage(img1, 0, 0, width + 5, height, this); // 根据给定的参数绘制图像
        repaint();
    }
    public void mouseClicked(MouseEvent e) { // 鼠标单击事件
    }
    public void mousePressed(MouseEvent e) { // 鼠标按下事件
        grap.drawImage(img3, 0, 0, width + 5, height, this); // 当鼠标被按下时所绘制的图像
        audioA.stop(); // audioA停止播放声音
        audioB.play(); // audioB开始播放声音
        la.setBackground(Color.black); // 设置标签的背景颜色
        la.setForeground(Color.red); // 设置标签的前景颜色
        la.setText("audioB is playing"); // 设置标签中要显示的内容
        this.add(la, BorderLayout.NORTH); // 添加标签组件
        repaint(); // 重新绘制组件
    }
    public void mouseReleased(MouseEvent e) { // 鼠标释放事件
        grap.drawImage(img2, 0, 0, width + 5, height, this);
        repaint();
        audioB.stop();
        audioA.play();
        la.setBackground(Color.red);
        la.setForeground(Color.black);
        la.setText("audioA is playing");
        this.add(la, BorderLayout.NORTH);
    }
    public void mouseEntered(MouseEvent e) { // 鼠标进入Applet所触发的事件
        grap.drawImage(img2, 0, 0, width, height, this);
        repaint();
    }
    public void mouseExited(MouseEvent e) { // 鼠标离开Applet所触发的事件
        grap.drawImage(img1, 0, 0, width, height, this);
        repaint();
    }
    public void paint(Graphics g) {
        g.drawImage(image, 0, 0, width, height, this);
    }
}