import javax.microedition.lcdui.Display;
            import javax.microedition.midlet.MIDlet;
            import javax.microedition.midlet.
            MIDletStateChangeException;
            /**
            * @author Jagie
            */
            public class SnakeMIDlet extends MIDlet
            {
            protected void startApp()
            throws MIDletStateChangeException
            {
            // TODO Auto-generated method stub
            Display.getDisplay(this)
            .setCurrent(new SnakeCanvas());
            }
            /* (non-Javadoc)
            * @see javax.microedition
            .midlet.MIDlet#pauseApp()
            */
            protected void pauseApp()
            {
            // TODO Auto-generated method stub
            }
            /* (non-Javadoc)
            * @see javax.microedition
            .midlet.MIDlet#destroyApp(boolean)
            */
            protected void destroyApp(boolean arg0)
            throws MIDletStateChangeException
            {
            // TODO Auto-generated method stub
            }
            }

import javax.microedition.lcdui.Canvas;
            import javax.microedition.lcdui.Graphics;
            /**
            * @author Jagie
            *
            */
            public class SnakeCanvas extends
            Canvas implements Runnable
            {
            Snake snake=new Snake();
            SnakeCanvas(){
            snake.init();
            new Thread(this).start();
            }
            protected void paint(Graphics g)
            {
            g.setColor(0);
            g.fillRect(0,0,this.getWidth(),
            this.getHeight());
            snake.paint(g);
            }
            /**
            * 游戏主线程，驱动蛇移动
            */
            public void run()
            {
            while(true){
            snake.move();
            repaint();
            try
            {
            Thread.sleep(50);
            } catch (InterruptedException e)
            {
            // TODO Auto-generated
            catch block
            e.printStackTrace();
            }
            }
            }
            /**
            * 按键相应,产生新蛇头
            */
            protected void keyPressed(int c)
            {
            int ga=this.getGameAction(c);
            switch (ga)
            {
            case Canvas.UP:
            snake.breakInto(1);
            break;
            case Canvas.DOWN:
            snake.breakInto(3);
            break;
            case Canvas.LEFT:
            snake.breakInto(4);
            break;
            case Canvas.RIGHT:
            snake.breakInto(2);
            break;
            }
            }
            }

import java.util.Vector;
            import javax.microedition.lcdui.Graphics;
            /**
            *
            * @author Jagie
            * 贪吃蛇
            */
            public class Snake
            {
            //蛇环节，每个环节为一个int[] sec
            //sec[0]:环节起点x,sec[1]:
            环节起点y,sec[2]:环节方向,sec[3]:
            环节长度
            Vector sections = new Vector();
            /**
            * 初始化sections
            * 开始的时候，整条蛇只有一段。
            *
            */
            public void init()
            {
            int[] head =
            { 10, 10, 2, 50 };
            sections.addElement(head);
            }
            /**
            * 绘制
            * @param g
            */
            public synchronized
            void paint(Graphics g)
            {
            if (sections.isEmpty())
            {
            return;
            }
            g.setColor(0, 255, 0);
            for (int i = 0; i < sections.size();
            i++)
            {
            int[] sec = (int[])
            sections.elementAt(i);
            //sec[0]:起点x,sec[1]:
            起点y,sec[2]:方向,sec[3]:
            长度
            switch (sec[2]) {
            case 1:
            g.drawLine(sec[0], sec[1],
            sec[0], sec[1] - sec[3]);
            break;
            case 2:
            g.drawLine(sec[0], sec[1],
            sec[0] + sec[3], sec[1]);
            break;
            case 3:
            g.drawLine(sec[0], sec[1],
            sec[0], sec[1] + sec[3]);
            break;
            case 4:
            g.drawLine(sec[0], sec[1],
            sec[0] - sec[3], sec[1]);
            break;
            }
            }
            }
            /**
            *
            * @author Jagie
            *
            * 蛇的爬行。本质上是蛇头长度++，蛇尾长度--。
            同时移动蛇尾起点。如果蛇尾长度小于0,则去掉蛇尾。
            */
            public synchronized void move()
            {
            if (sections.isEmpty())
            {
            return;
            }
            //蛇尾
            int[] tail = (int[])
            sections.elementAt
            (sections.size() - 1);
            //蛇头
            int[] head = (int[])
            sections.elementAt(0);
            //根据蛇尾环节的方向移动蛇尾。
            switch (tail[2])
            {
            case 1:
            tail[1]--;
            break;
            case 2:
            tail[0]++;
            break;
            case 3:
            tail[1]++;
            break;
            case 4:
            tail[0]--;
            break;
            }
            //蛇尾缩短
            tail[3]--;
            //蛇头增长
            head[3]++;
            //蛇尾<0,则去掉蛇尾
            if (tail[3] <= 0)
            {
            sections.removeElement(tail);
            }
            }
            /**
            * 蛇分段
            * @param dir 新蛇头的方向
            */
            public synchronized void
            breakInto(int dir)
            {
            if (sections.isEmpty())
            {
            return;
            }
            int[] head = (int[])
            sections.elementAt(0);
            //新蛇头方向和旧蛇头方向一致，
            则无反应。
            //TODO 可以考虑加速。
            if (dir == head[2])
            {
            return;
            }
            //增加新蛇头
            int[] newhead=new int[4];
            //新蛇头的起始位置，
            与旧蛇头的运动方向有关。
            switch (head[2])
            {
            case 1:
            newhead[0]=head[0];
            newhead[1]=head[1]-head[3];
            newhead[2]=dir;
            newhead[3]=0;
            //蛇头总是第一个元素
            sections.insertElementAt(newhead, 0);
            break;
            case 2:
            newhead[0]=head[0]+head[3];
            newhead[1]=head[1];
            newhead[2]=dir;
            newhead[3]=0;
            sections.insertElementAt(newhead, 0);
            break;
            case 3:
            newhead[0]=head[0];
            newhead[1]=head[1]+head[3];
            newhead[2]=dir;
            newhead[3]=0;
            sections.insertElementAt(newhead, 0);
            break;
            case 4:
            newhead[0]=head[0]-head[3];
            newhead[1]=head[1];
            newhead[2]=dir;
            newhead[3]=0;
            sections.insertElementAt(newhead, 0);
            break;
            }
            }
            }