最近要重新学习Java，找个例子来实践，在网上找了很多例程来看，自己重新编写了一个贪食蛇的例子，记在这里。

1.SnakeModel.java

import java.util.Observable;

import java.util.LinkedList;

import java.util.Arrays;

import java.util.Random;

import javax.swing.*;

//Observable类一般代表数据，实现接口Runnable表明创建一个进程

public class SnakeModel extends Observable implements Runnable {

boolean[][] matrix;//指示位置上是否有蛇体或食物；

LinkedList nodeArray = new LinkedList(); //蛇体

Node food;

int maxX;//X轴边线，即为画布中X轴个数

int maxY;//y轴边线，即为画布中Y轴个数

int direction = UP; //蛇运行的方向,初始为向上(UP)

boolean isRunning = false; //运行状态

int timeInterval = 200; //时间间隔，毫秒级

double speedChangeRate = 0.75; //每次的速度变化率

boolean isPaused = false ;//暂停标志

int score = 0; //得分

int countMove = 0; //吃到食物前移动的次数

public static final int UP = 2;

public static final int DOWN =4;

public static final int LEFT= 1;

public static final int RIGHT =3;

public SnakeModel(int maxX, int maxY){

this.maxX = maxX;

this.maxY = maxY;

reset();

}

public void reset(){

direction = SnakeModel.UP;

timeInterval = 200;

isPaused = false;

score = 0;

countMove = 0;

//初始化矩阵

matrix = new boolean[maxX][];

for(int i = 0; i < maxX; ++i){

//关于数组的新建

matrix[i] = new boolean[maxY];

Arrays.fill(matrix[i],false);

}

//初始化蛇体

//初始蛇体长度按照横轴的长度，若横轴>20,则蛇体长度为10，否则为横轴一半

int initArrayLength = maxX > 20 ? 10 : maxX / 2;

nodeArray.clear();

for(int i = 0; i < initArrayLength; ++i){

int x = maxX / 2;

int y = maxY / 2;

nodeArray.addLast(new Node(x, y));

matrix[x][y] = true;

}

//创建食物

food = createFood();

matrix[food.x][food.y] = true;

}

public void changeDirection(int newDirection){

//改变方向不能与原方向同向或反向

if((direction & 1) != (newDirection & 1)){

direction = newDirection;

}

}

//移动一格

public boolean moveOn(){

Node n = (Node) nodeArray.getFirst();

int x = n.x;

int y = n.y;

//根据方向增减坐标,这里的增减是以数组平面的，而不是普通的坐标轴

switch(direction){

case UP:

y--;break;//向上时，数组的y变小

case DOWN:

y++;break;//向下时，数组的y变大

case LEFT:

x--;break;

case RIGHT:

x++;break;

}

//如果新坐标落在有效范围内，则进行处理

if((0<=x && x

if(matrix[x][y]){//如果新坐标的点上有东西(蛇体或食物)

if( x==food.x && y==food.y){//吃到食物，成功

nodeArray.addFirst(food);//从蛇头增长

int scoreGet = (10000 - 200 * countMove) / timeInterval;

//计分标准为最低10分

score += (scoreGet > 10) ? scoreGet : 10;

//countMove清0，重新计算，因为countMove越大，得到的分数越低

//countMove的涵义是吃到食物前移动的次数

countMove = 0;

food = createFood(); //创建新的食物

matrix[food.x][food.y] = true;

return true;

}else{//吃到蛇体本身，失败

return false;

}

}else{//如果坐标上没有东西，移动蛇体

nodeArray.addFirst(new Node(x, y));

matrix[x][y] = true;

n = (Node) nodeArray.removeLast();

matrix[n.x][n.y] = false;

countMove++;

return true;

}

}

return false; //触到边线，失败

}

//作为线程运行的主体，测试时的入口

public void run(){

isRunning = true;

while(isRunning){

try{

Thread.sleep(timeInterval);

}catch(Exception e){

break;

}

if(!isPaused){

if(moveOn()){//没有触碰到蛇体或者墙壁

//标记此 Observable 对象为已改变的对象；现在 hasChanged 方法将返回 true。

//这时，Observer会自动调用update方法

setChanged();

//则通知其所有观察者，并调用 clearChanged 方法来指示此对象不再改变。

notifyObservers();

}else{//挂掉了

JOptionPane.showMessageDialog(null, "","You failed。Game Over!",

JOptionPane.INFORMATION_MESSAGE);

break;

}

}

}

isRunning = false;

}

private Node createFood(){

int x = 0;

int y = 0;

//随机获取一个有效区域内的蛇体和食物不重叠的位置

do{

Random r = new Random();

// 返回一个伪随机数，它是取自此随机数生成器序列的、在 0(包括)

// 和指定值(不包括)之间均匀分布的 int 值。

x = r.nextInt(maxX);

y = r.nextInt(maxY);

}while(matrix[x][y]);

return new Node(x, y);

}

public void speedUp(){

timeInterval *= speedChangeRate;

}

public void speedDown(){

timeInterval /= speedChangeRate;

}

public void changePauseState(){

isPaused = !isPaused;

}

public String toString(){

String result = "";

for(int i = 0 ; i < nodeArray.size(); ++i ){

Node n = (Node) nodeArray.get(i);

result += "[" + n.x + "," + n.y + "]";

}

return result;

}

}

class Node{

int x;

int y;

Node(int x, int y){

this.x = x;

this.y = y;

}

}

2.SnakeControl.java

import java.awt.event.*;

import java.awt.event.KeyEvent.*;

public class SnakeControl implements KeyListener{

SnakeModel model;

public SnakeControl(SnakeModel model){

this.model = model;

}

public void keyPressed(KeyEvent e){

int keyCode = e.getKeyCode();

if(model.isRunning){//运行状态下，处理按键

switch(keyCode){

case KeyEvent.VK_UP:

model.changeDirection(SnakeModel.UP);

break;

case KeyEvent.VK_DOWN:

model.changeDirection(SnakeModel.DOWN);

break;

case KeyEvent.VK_LEFT:

model.changeDirection(SnakeModel.LEFT);

break;

case KeyEvent.VK_RIGHT:

model.changeDirection(SnakeModel.RIGHT);

break;

case KeyEvent.VK_ADD:

case KeyEvent.VK_PAGE_UP:

model.speedUp();

break;

case KeyEvent.VK_SUBTRACT:

case KeyEvent.VK_PAGE_DOWN:

model.speedDown();

break;

case KeyEvent.VK_SPACE:

case KeyEvent.VK_P:

model.changePauseState();

break;

case KeyEvent.VK_R:

case KeyEvent.VK_ENTER:

model.reset();

break;

default:

}

}

}

public void keyTyped(KeyEvent e){

}

public void keyReleased(KeyEvent e){

}

}

3.SnakeView.java

import javax.swing.*;

import java.awt.*;

import java.util.*;

public class SnakeView implements Observer{

SnakeControl control = null;

SnakeModel model = null;

JFrame mainFrame;

Canvas paintCanvas;

JLabel labelScore;

public static final int canvasWidth = 300;

public static final int canvasHeight = 300;

public static final int nodeWidth = 10;

public static final int nodeHeight = 10;

public SnakeView(SnakeModel model, SnakeControl control){

this.model = model;

this.control = control;

mainFrame = new JFrame("Snake");

Container cp = mainFrame.getContentPane();

//创建顶部的分数显示

labelScore = new JLabel("Score:");

cp.add(labelScore, BorderLayout.NORTH);

//创建中间的游戏显示区域、

paintCanvas = new Canvas();

paintCanvas.setSize(canvasWidth + 1, canvasHeight+1);

paintCanvas.addKeyListener(control);

cp.add(paintCanvas, BorderLayout.CENTER);

//创建地下的帮助栏

JPanel panelButton = new JPanel();

panelButton.setLayout(new BorderLayout());

JLabel labelHelp;

labelHelp = new JLabel("PageUp, PageDown for speed;", JLabel.CENTER);

panelButton.add(labelHelp, BorderLayout.NORTH);

labelHelp = new JLabel("ENTER or R or S for start;", JLabel.CENTER);

panelButton.add(labelHelp, BorderLayout.CENTER);

labelHelp = new JLabel("SPACE or P for pause", JLabel.CENTER);

panelButton.add(labelHelp, BorderLayout.SOUTH);

cp.add(panelButton, BorderLayout.SOUTH);

mainFrame.addKeyListener(control);

mainFrame.pack();

mainFrame.setResizable(false);

mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

mainFrame.setVisible(true);

}

void repaint(){

Graphics g = paintCanvas.getGraphics();

//设置背景

g.setColor(Color.WHITE);

g.fillRect(0, 0, canvasWidth, canvasHeight);

//在画布上画蛇

g.setColor(Color.BLACK);

LinkedList na = model.nodeArray;

Iterator it = na.iterator();

while(it.hasNext()){

Node n = (Node)it.next();

drawNode(g, n);

}

//画食物

g.setColor(Color.RED);

Node n = model.food;

drawNode(g, n);

//更新分数

updateScore();

}

private void drawNode(Graphics g, Node n){

//矩形周围留空，提高视觉效果

g.fillRect(n.x*nodeWidth, n.y*nodeHeight, nodeWidth-1, nodeHeight-1);

}

public void updateScore(){

String s = "Score: " + model.score;

labelScore.setText(s);

}

public void update(Observable o, Object arg){

repaint();

}

}

4.Snake.java

public class Snake {

public static void main(String[] args) {

SnakeModel model = new SnakeModel(30, 30);

SnakeControl control = new SnakeControl(model);

SnakeView view = new SnakeView(model, control);

//添加一个观察者，让view成为model的观察者

model.addObserver(view);

//Thread的start方法会自动调用该线程的run()方法

(new Thread(model)).start();

}

}