java中多个窗口同时买票的并发三种安全实现方式

1.线程实现runable接口(同步中的this可以为任一相同的对象)

首先介绍线程中常用的几个方法如下：

void start()            使该线程开始执行；Java虚拟机调用该线程的
run 

static ThreadcurrentThread()    返回对当前正在执行的线程对象的引用。

StringgetName()           返回该线程的名称。

static voidsleep(long millis)     在指定的毫秒数内让当前正在执行的线程休眠

publicclass ThreadDemo {

publicstaticvoid main(String[]args) {

SaleTickets window = new SaleTickets();

new Thread(window,"窗口1").start();

new Thread(window,"窗口2").start();

new Thread(window,"窗口3").start();

new Thread(window,"窗口4").start();

}

}

class SaleTickets implementsRunnable {

private int tickets = 100;

publicvoid run() {

while (true) {

synchronized (this) {

try {

Thread.sleep(20);

} catch(InterruptedException e) {

e.printStackTrace();

}

if (tickets > 0) {

System.out.println(Thread.currentThread().getName()+ "正在发售第" + (101 - tickets) +"张票");

} else {

break;

}

tickets--;

}

}

}

}

2.synchronized修饰同步方法，不允许并发。

public class ThreadDemo {
public static void main(String[] args) {
SaleTickets window = new SaleTickets();
new Thread(window, "窗口1").start();
new Thread(window, "窗口2").start();
new Thread(window, "窗口3").start();
new Thread(window, "窗口4").start();
}
}

class SaleTickets implements Runnable {
private int tickets = 100;

public void run() {
while (true) {
sale();
if (tickets < 0) {
break;
}
}
}

synchronized public void sale() {
try {
Thread.sleep(20);
} catch (InterruptedException e) {
e.printStackTrace();
}
if (tickets > 0) {
System.out.println(Thread.currentT
9404
hread().getName() + "正在发售第" + (101 - tickets) + "张票");
}
tickets--;
}
}

3.可重入锁机制。

import java.util.concurrent.locks.ReentrantLock;

public class LockDemo {

public static void main(String[] args) {
SaleTicket window = new SaleTicket();
new Thread(window, "窗口1").start();
new Thread(window, "窗口2").start();
new Thread(window, "窗口3").start();
new Thread(window, "窗口4").start();
}

}

class SaleTicket implements Runnable {
private int tickets = 100;
ReentrantLock lock = new ReentrantLock();

public void run() {
while (true) {
Sale();
if (tickets <= 0) {
break;
}
}
}

public void Sale() {
lock.lock();
try {
if (tickets > 0) {
System.out.println(Thread.currentThread().getName() + "正在发售第" + tickets + "票");
Thread.sleep(30);
tickets--;
}
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
lock.unlock();
}

}
}