最近在搞一个弹球游戏，其中，用到了Java多线程的应用，首先，先说一下，什么叫做线程。或许大家都知道进程是什么，打开电脑的任务管理器，可以看到，里面有进程这个选项，非常明显，进程就是一个程序，而每个程序，有由多个线程组成。好了，这样说的不清不楚的，那么好，我用一个弹球小游戏来解释一下，那样可能大家会更容易理解些。
import java.awt.Insets;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;/*** 游戏界面类* * @author Administrator* */public class GameUI extends javax.swing.JFrame {private static GameUI UI;private java.awt.Graphics g;private MyListener ml;public javax.swing.JLabel text_field;public javax.swing.JProgressBar pBar;private String command;public java.util.ArrayList<MyThread> list = new java.util.ArrayList<MyThread>();private javax.swing.JToggleButton button;public static void main(String args[]) {UI = new GameUI();UI.initUI();}/*** 初始化窗体的方法*/public void initUI() {// 设置标题this.setTitle("是高手就坚持100s");// 设置大小this.setSize(610, 635);// 设置关闭是退出程序this.setDefaultCloseOperation(3);// 设置打开窗体时在屏幕中间显示this.setLocationRelativeTo(null);// 设置窗体的流式布局管理器this.setLayout(new java.awt.FlowLayout());// 设置窗体背景颜色this.getContentPane().setBackground(java.awt.Color.black);// 创建文本标签对象text_field = new javax.swing.JLabel();javax.swing.JLabel lable = new javax.swing.JLabel("时 间 ：");// 设置文本标签前景颜色lable.setForeground(java.awt.Color.red);text_field.setForeground(java.awt.Color.red);// 创建进度条对象pBar = new javax.swing.JProgressBar(0, 330);// 创建按钮对象button = new javax.swing.JToggleButton();button.setMargin(new Insets(0, 0, 0, 0));button.setIcon(new javax.swing.ImageIcon("images/Pause.gif"));button.setActionCommand("暂停");// 通过匿名内部类来创建动作监听器java.awt.event.ActionListener button_listener = new java.awt.event.ActionListener() {public void actionPerformed(ActionEvent e) {String com = e.getActionCommand();if (com.equals("暂停")) {button.setMargin(new Insets(0, 0, 0, 0));button.setIcon(new javax.swing.ImageIcon("images/start.gif"));button.setActionCommand("继续");for (int i = 0; i < list.size(); i++) {list.get(i).PauseThread();}}if (com.equals("继续")) {button.setMargin(new Insets(0, 0, 0, 0));button.setIcon(new javax.swing.ImageIcon("images/Pause.gif"));button.setActionCommand("暂停");for (int i = 0; i < list.size(); i++) {list.get(i).ContinueThread();}}}};button.addActionListener(button_listener);this.add(button);this.add(lable);this.add(pBar);this.add(text_field);// 的到菜单条javax.swing.JMenuBar bar = creatMenuBar();// 为窗体设置菜单条this.setJMenuBar(bar);// 设置窗体的可见性this.setVisible(true);}/*** 创建菜单条的方法* * @return*/public javax.swing.JMenuBar creatMenuBar() {// 创建菜单条对象javax.swing.JMenuBar bar = new javax.swing.JMenuBar();// 创建菜单对象javax.swing.JMenu menu_menu = new javax.swing.JMenu("菜单");javax.swing.JMenu difficulty_menu = new javax.swing.JMenu("难度");javax.swing.JMenu help_menu = new javax.swing.JMenu("帮助");// 创建菜单选项对象javax.swing.JMenuItem star_item = new javax.swing.JMenuItem("开始");javax.swing.JMenuItem exit_item = new javax.swing.JMenuItem("退出");javax.swing.JMenuItem help_item = new javax.swing.JMenuItem("游戏说明");javax.swing.JMenuItem about_item = new javax.swing.JMenuItem("关于");// 创建单选选项javax.swing.JRadioButtonMenuItem easy_item = new javax.swing.JRadioButtonMenuItem("简单");javax.swing.JRadioButtonMenuItem middle_item = new javax.swing.JRadioButtonMenuItem("中等");javax.swing.JRadioButtonMenuItem hard_item = new javax.swing.JRadioButtonMenuItem("困难");// 创建一个按钮组javax.swing.ButtonGroup group = new javax.swing.ButtonGroup();// 将单选按钮添加到按钮组中group.add(easy_item);group.add(middle_item);group.add(hard_item);// 将单选按钮添加到菜单中difficulty_menu.add(easy_item);difficulty_menu.add(middle_item);difficulty_menu.add(hard_item);// 通过匿名内部类来创建动作监听器ActionListener listener = new java.awt.event.ActionListener() {public void actionPerformed(ActionEvent e) {command = e.getActionCommand();// 如果选择开始，则创建线程对象if (command.equals("开始") && list.size() == 0) {creatBall(20, 1);}// 如果选择退出按钮，则退出程序if (command.equals("退出")) {System.exit(0);}// 如果选择简单按钮if (command.equals("简单") && list.size() == 0) {creatBall(20, 1);}// 如果选择中等按钮if (command.equals("中等") && list.size() == 0) {creatBall(50, 2);}if (command.equals("困难") && list.size() == 0) {creatBall(40, 2);}if (command.equals("游戏说明")) {javax.swing.JOptionPane.showMessageDialog(null,"移动鼠标，用挡板接球，如果接不住，就算输了……\n游戏可以选择难度，包括简单、中等、困难");}if (command.equals("关于")) {javax.swing.JOptionPane.showMessageDialog(null,"这是一个用Java编写的小游戏……\n制作人：沈冠军\n时间：8月\n版权所有,翻版必究！");}}};// 添加动作监听器star_item.addActionListener(listener);exit_item.addActionListener(listener);easy_item.addActionListener(listener);middle_item.addActionListener(listener);hard_item.addActionListener(listener);help_item.addActionListener(listener);about_item.addActionListener(listener);// 将菜单选项对象添加到菜单对象上menu_menu.add(star_item);menu_menu.add(exit_item);help_menu.add(help_item);help_menu.add(about_item);// 将菜单对象添加到菜单条上bar.add(menu_menu);bar.add(difficulty_menu);bar.add(help_menu);// 返回菜单条对象return bar;}/*** 创建线程对象的方法* * @param speed* ：速度* */public void creatBall(int speed, int num) {java.util.Random ran = new java.util.Random();if (ml == null) {g = UI.getGraphics();ml = new MyListener(g);UI.addMouseListener(ml);UI.addMouseMotionListener(ml);}for (int i = 0; i < num; i++) {int x = ran.nextInt(600) + 10;int y = ran.nextInt(300) + 100;MyThread th = new MyThread(g, ml, UI, x, y, speed);list.add(th);th.start();}}/*** 得到命令的方法*/public String getCommand() {return command;}}import java.awt.Color;import javax.swing.JOptionPane;
/*** 线程类* * @author Administrator* */public class MyThread extends Thread {private int width = 20, height = 20;private int x, y;private java.awt.Graphics g;private GameUI UI;private boolean isexist = true;private MyListener listener;private int speed;private int x1 = 12, y1 = 12;private long start, end;private long last_time;private int response;private boolean isFinish = true;private boolean isPause = true;private java.util.ArrayList<MyThread> list;private float value = 320;private java.awt.Color color = java.awt.Color.blue;/** 重写构造器*/public MyThread(java.awt.Graphics g, MyListener listener, GameUI UI, int x,int y, int speed) {this.g = g;this.UI = UI;this.x = x;this.y = y;this.speed = speed;this.listener = listener;}/** (non-Javadoc)重写run的方法* * @see java.lang.Thread#run()*/public void run() {drawOval();}/*** 创建线程的方法*/public void drawOval() {start = System.currentTimeMillis();while (isFinish) {while (isPause) {synchronized(this.g){// 画一个圆g.setColor(java.awt.Color.black);g.fillOval(x, y, width, height);x += x1;y += y1;getColors();g.setColor(color);g.fillOval(x, y, width, height);}int x2 = listener.getX();if (x > 580) {x1 = -12;}if (x < 10) {x1 = 12;}if (y < 90) {y1 = 12;}if (y > 595 && x > x2 && x < x2 + 100) {y1 = -12;}if (y > 630) {if (isexist) {isAgain();}stopThread();}try {Thread.sleep(speed);value -= 0.1;} catch (Exception ef) {ef.printStackTrace();}// 将前一次画的清除掉end = System.currentTimeMillis();last_time = 100 - (end - start) / 1000;UI.text_field.setText(last_time + "s");UI.pBar.setValue((int) value);if (last_time == 0) {list = UI.list;for (int j = 0; j < list.size(); j++) {// 停在线程，并且去掉最后一个圆list.get(j).stopThread();list.get(j).fadeOval();}stopThread();showDialog();}}}}/*** 线程结束时消去最后一个圆的方法*/public void fadeOval() {g.setColor(java.awt.Color.black);g.fillOval(x, y, width, height);}/*** 重来对话框的处理方法*/public void isAgain() {isexist = false;list = UI.list;System.out.println(list.size());for (int j = 0; j < list.size(); j++) {// 停在线程，并且去掉最后一个圆list.get(j).stopThread();list.get(j).fadeOval();}Object[] options = { "是", "否" };String command = UI.getCommand();response = JOptionPane.showOptionDialog(null,"哈哈，你输了！不要灰心\n坚持就是胜利，是否再来一次？", null, JOptionPane.YES_OPTION,JOptionPane.NO_OPTION, null, options, null);System.out.println(response);if (response == 0) {if (command.equals("简单") || command.equals("开始")) {AgainThread();if (list.size() != 0) {// 现将原来的对象从队列中移除list.removeAll(list);UI.creatBall(20, 1);}}if (command.equals("中等")) {AgainThread();if (list.size() != 0) {list.removeAll(list);UI.creatBall(50, 2);}}if (command.equals("困难")) {AgainThread();if (list.size() != 0) {list.removeAll(list);UI.creatBall(40, 2);}}}// 如果点击关闭，则将线程对象从队列中移除if (response == -1 || response == 1) {list.removeAll(list);}}/*** 停止线程的方法*/public void stopThread() {isFinish = false;isPause = false;}/*** 暂停线程的方法*/public void PauseThread() {isPause = false;}/*** 继续线程的方法*/public void ContinueThread() {isPause = true;}/*** 是否重来的方法*/public void AgainThread() {isFinish = true;isPause = true;}public void getColors() {if (x % 2 == 0 && y % 2 == 0) {color = java.awt.Color.green;}if (x % 2 == 0 && y % 2 != 0) {color = java.awt.Color.red;}if (x % 2 != 0 && y % 2 != 0) {color = java.awt.Color.orange;}if (x % 2 != 0 && y % 2 != 0) {color = java.awt.Color.yellow;}}public void showDialog() {javax.swing.JOptionPane.showInputDialog("好样的，你是真的高手，\n恭喜你坚持了100s\n请输入您的大名");}}
import java.awt.event.KeyEvent;import java.awt.event.MouseEvent;import javax.swing.JFrame;/*** 鼠标监听器的类* * @author Administrator* */public class MyListener extends java.awt.event.MouseAdapter {private java.awt.Graphics g;private int x = 5, y = 620;private int width = 100, height = 10;public MyListener(java.awt.Graphics g) {this.g = g;}public void mouseMoved(MouseEvent e) {// 设置画布对象颜色synchronized (this.g) {g.setColor(java.awt.Color.black);g.fillRect(x, y, width, height);x = e.getX();g.setColor(java.awt.Color.green);g.fillRect(x, y, width, height);}}/*** 得到x的方法* * @return：x*/public int getX() {return x;}}
界面效果图：
好了，大家看到了，线程的作用就是在一个程序中可以同时做不、同的事，就像上面的 弹球游戏，它可以在画矩形的同时画圆，两个可以同时发生，当选择难度时可以看都，可以同时画多个球。
