多线程售票系统（包含三种常见的线程安全策略）
创建多线程的四种方法
1、继承Thread类（不推荐）；
2、实现Runnable接口；
3、实现Callable接口；
4、线程池（推荐）。
常见的三种线程安全策略
1、同步代码块；
2、同步方法；
3、同步锁。
示例：实现Runnable接口
public class SellTicket implements Runnable {
private int ticktNum = 121;
Object obj = new Object();
@Override
public void run() {
//同步代码块解决线程安全问题。
synchronized (obj) {
while (ticktNum > 0) {
// 开始出票
// 线程名称
String name = Thread.currentThread().getName();
// 票数相减
System.out.println("线程名称：" + name + " 票号：" + ticktNum--);
}
}
}
}
public class Tx {
public static void main(String[] args) {
SellTicket st=new SellTicket();
Thread thread1 = new Thread(st, "窗口1");
Thread thread2 = new Thread(st, "窗口2");
Thread thread3 = new Thread(st, "窗口3");
Thread thread4 = new Thread(st, "窗口4");
Thread thread5 = new Thread(st, "窗口5");
thread1.start();
thread2.start();
thread3.start();
thread4.start();
thread5.start();
}
}
示例：实现Callable接口
import java.util.concurrent.Callable;
public class SellTicket implements Callable {
private int ticktNum = 100;
@Override
public Integer call() throws Exception {
sellTicket();
//返回剩余票数
return ticktNum;
}
//同步方法解决线程安全问题。
private synchronized void sellTicket() throws Exception{
while (ticktNum > 0) {
Thread.sleep(10);
// 开始出票
// 线程名称
String name = Thread.currentThread().getName();
// 票数相减
System.out.println("线程名称：" + name + " 票号：" + ticktNum--);
}
}
}
import java.util.concurrent.FutureTask;
public class Tx {
public static void main(String[] args) throws Exception {
FutureTask task = new FutureTask(new SellTicket());
Thread thread1 = new Thread(task);
Thread thread2 = new Thread(task);
Thread thread3 = new Thread(task);
Thread thread4 = new Thread(task);
Thread thread5 = new Thread(task);
thread1.start();
thread2.start();
thread3.start();
thread4.start();
thread5.start();
// 返回值
System.out.println(task.get());
}
}
示例：线程池
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
//注意：ExecutorService需要已经实现了Runnable的类来配合使用。
public class SellTicket implements Runnable {
private int ticktNum = 10;
Object obj = new Object();
// true表示公平锁，默认false表示非公平锁。
Lock lock = new ReentrantLock(true);
@Override
public void run() {
// 同步锁块解决线程安全问题。
while (true) {
//开启锁
lock.lock();
if (ticktNum > 0) {
try {
// 开始出票
// 线程名称
String name = Thread.currentThread().getName();
// 票数相减
System.out.println("线程名称：" + name + " 票号：" + ticktNum--);
} catch (Exception e) {
// TODO: handle exception
} finally {
// 释放锁
lock.unlock();
}
}else {
break;
}
}
}
}
public class Tx {
public static void main(String[] args) throws Exception {
ExecutorService executorService=Executors.newFixedThreadPool(5);
SellTicket sellTicket = new SellTicket();
executorService.execute(sellTicket);
executorService.execute(sellTicket);
executorService.execute(sellTicket);
executorService.execute(sellTicket);
executorService.execute(sellTicket);
}
}
作者：陈天相
