第6 章 ： 多线程综合案例
23 数字加减
4个线程，2个线程加，2个线程减
循环出现 加一个，减一个
// 资源 class Resource { private int count = 0; // 为false可以增加,加完了设置为true， // 为true可以减少，减完了设置为false private boolean flag = false; public synchronized void add() { if (this.flag == true) { try { super.wait(); } catch (InterruptedException e) { e.printStackTrace(); } } try { Thread.sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } this.count++; System.out.println(Thread.currentThread().getName() + " count=" + count); this.flag = true; super.notifyAll(); } public synchronized void sub() { if (this.flag == false) { System.out.println(this.flag); try { super.wait(); } catch (InterruptedException e) { e.printStackTrace(); } } try { Thread.sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } this.count--; System.out.println(Thread.currentThread().getName() + " count=" + count); this.flag = false; super.notifyAll(); } } // 加法线程 class AddThread implements Runnable { private Resource resource; public AddThread(Resource resource) { this.resource = resource; } @Override public void run() { for (int i = 0; i < 10; i++) { this.resource.add(); } } } // 减法线程 class SubThread implements Runnable { private Resource resource; public SubThread(Resource resource) { this.resource = resource; } @Override public void run() { for (int i = 0; i < 10; i++) { this.resource.sub(); } } } class Demo { public static void main(String[] args) { Resource resource = new Resource(); AddThread at = new AddThread(resource); SubThread st = new SubThread(resource); new Thread(at, "加法线程-A").start(); new Thread(at, "加法线程-B").start(); new Thread(st, "减法线程-X").start(); new Thread(st, "减法线程-Y").start(); } }
并没有出现一加一减的现象
24 生产电脑
生产一台搬运一台
消费者生产者模型
class Computer{ private static int count; public Computer() { count++; } @Override public String toString() { return "电脑编号：" + count; } } class Resource{ private Computer computer; public synchronized void make(){ if(computer != null){ try { wait(); } catch (InterruptedException e) { e.printStackTrace(); } } try { Thread.sleep(100); } catch (InterruptedException e) { e.printStackTrace(); } this.computer = new Computer(); System.out.println("生产：" + this.computer); notifyAll(); } public synchronized void get(){ if(computer == null){ try { wait(); } catch (InterruptedException e) { e.printStackTrace(); } } try { Thread.sleep(10); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println("取走：" + this.computer); this.computer = null; notifyAll(); } } class Producer implements Runnable{ private Resource resource; public Producer(Resource resource) { this.resource = resource; } @Override public void run() { for (int i = 0; i < 10; i++) { resource.make(); } } } class Consumer implements Runnable{ private Resource resource; public Consumer(Resource resource) { this.resource = resource; } @Override public void run() { for (int i = 0; i < 10; i++) { resource.get(); } } } class Demo{ public static void main(String[] args) { Resource resource = new Resource(); new Thread(new Producer(resource)).start(); new Thread(new Consumer(resource)).start(); } }
25 竞争抢答
3个抢答线程，同时发出抢答指令
成功和失败都给与提示
有数据返回，采用Callable方式
import java.util.concurrent.Callable; import java.util.concurrent.FutureTask; class MyThread implements Callable<String> { private boolean flag = false; @Override public String call() throws Exception { synchronized (this) { // 如果没有人抢答成功则可以抢答 if (this.flag == false) { this.flag = true; return Thread.currentThread().getName() + "抢答成功！"; } else { return Thread.currentThread().getName() + "抢答失败！"; } } } } class Demo { public static void main(String[] args) throws Exception { MyThread t = new MyThread(); FutureTask<String> task1 = new FutureTask<String>(t); FutureTask<String> task2 = new FutureTask<String>(t); FutureTask<String> task3 = new FutureTask<String>(t); new Thread(task1, "抢答者A").start(); new Thread(task2, "抢答者B").start(); new Thread(task3, "抢答者C").start(); System.out.println(task1.get()); System.out.println(task2.get()); System.out.println(task3.get()); } }
