[Java基础]线程同步之卖票案列分析

案列:
卖票。

需求:
某电影院目前正在上映国产大片，共有100张票，而它有3个窗口卖票，请设计一个程序模拟该电影院卖票。

代码如下:

package SellTicketPack;public class SellTicket implements Runnable{private int tickets = 100;@Overridepublic void run() {while (true) {if (tickets > 0) {System.out.println(Thread.currentThread().getName() + "正在出售第" + tickets + "张票");tickets--;}}}
}

package SellTicketPack;public class SellTicketDemo {public static void main(String[] args){SellTicket st = new SellTicket();Thread t1 = new Thread(st,"窗口1");Thread t2 = new Thread(st,"窗口2");Thread t3 = new Thread(st,"窗口3");t1.start();t2.start();t3.start();}
}

在这里插入图片描述
代码如下:

package SellTicketPack;public class SellTicket implements Runnable{private int tickets = 100;@Overridepublic void run() {while (true) {if (tickets > 0) {try {Thread.sleep(100);} catch (InterruptedException e) {e.printStackTrace();}System.out.println(Thread.currentThread().getName() + "正在出售第" + tickets + "张票");tickets--;}}}}

package SellTicketPack;public class SellTicketDemo {public static void main(String[] args){SellTicket st = new SellTicket();Thread t1 = new Thread(st,"窗口1");Thread t2 = new Thread(st,"窗口2");Thread t3 = new Thread(st,"窗口3");t1.start();t2.start();t3.start();}}

在这里插入图片描述

在这里插入图片描述
代码如下:

package SellTicketPack;public class SellTicket implements Runnable{private int tickets = 100;private Object obj = new Object();@Overridepublic void run() {while (true) {synchronized (obj) {if (tickets > 0) {try {Thread.sleep(100);} catch (InterruptedException e) {e.printStackTrace();}System.out.println(Thread.currentThread().getName() + "正在出售第" + tickets + "张票");tickets--;}}}}}

在这里插入图片描述

同步方法:
代码如下:

package SellTicketPack;public class SellTicket implements Runnable{private int tickets = 100;private Object obj = new Object();private int x = 0;@Overridepublic void run() {while (true) {if (x%2==0) {
//                synchronized (obj)synchronized (this){if (tickets > 0) {try {Thread.sleep(100);} catch (InterruptedException e) {e.printStackTrace();}System.out.println(Thread.currentThread().getName() + "正在出售第" + tickets + "张票");tickets--;}}}else{
//                synchronized (obj) {
//                    if (tickets > 0) {
//                        try {
//                            Thread.sleep(100);
//                        } catch (InterruptedException e) {
//                            e.printStackTrace();
//                        }
//                        System.out.println(Thread.currentThread().getName() + "正在出售第" + tickets + "张票");
//                        tickets--;
//                    }
//                }sellTicket();}x++;}}//    private void sellTicket() {
//        synchronized (obj) {
//            if (tickets > 0) {
//                try {
//                    Thread.sleep(100);
//                } catch (InterruptedException e) {
//                    e.printStackTrace();
//                }
//                System.out.println(Thread.currentThread().getName() + "正在出售第" + tickets + "张票");
//                tickets--;
//            }
//        }
//    }private synchronized void sellTicket() {if (tickets > 0) {try {Thread.sleep(100);} catch (InterruptedException e) {e.printStackTrace();}System.out.println(Thread.currentThread().getName() + "正在出售第" + tickets + "张票");tickets--;}}}

同步静态方法:
代码如下:

package SellTicketPack;public class SellTicket implements Runnable{
//    private int tickets = 100;private static int tickets = 100;private Object obj = new Object();private int x = 0;@Overridepublic void run() {while (true) {if (x%2==0) {
//                synchronized (obj)
//                synchronized (this)synchronized (SellTicket.class){if (tickets > 0) {try {Thread.sleep(100);} catch (InterruptedException e) {e.printStackTrace();}System.out.println(Thread.currentThread().getName() + "正在出售第" + tickets + "张票");tickets--;}}}else{
//                synchronized (obj) {
//                    if (tickets > 0) {
//                        try {
//                            Thread.sleep(100);
//                        } catch (InterruptedException e) {
//                            e.printStackTrace();
//                        }
//                        System.out.println(Thread.currentThread().getName() + "正在出售第" + tickets + "张票");
//                        tickets--;
//                    }
//                }sellTicket();}x++;}}//    private void sellTicket() {
//        synchronized (obj) {
//            if (tickets > 0) {
//                try {
//                    Thread.sleep(100);
//                } catch (InterruptedException e) {
//                    e.printStackTrace();
//                }
//                System.out.println(Thread.currentThread().getName() + "正在出售第" + tickets + "张票");
//                tickets--;
//            }
//        }
//    }private static synchronized void sellTicket() {if (tickets > 0) {try {Thread.sleep(100);} catch (InterruptedException e) {e.printStackTrace();}System.out.println(Thread.currentThread().getName() + "正在出售第" + tickets + "张票");tickets--;}}}

在这里插入图片描述

代码如下：

package SellTicketPack02;import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;public class SellTicket implements Runnable{private int tickets = 100;private Lock lock = new ReentrantLock();@Overridepublic void run() {while (true) {try{lock.lock();if (tickets > 0) {try {Thread.sleep(100);} catch (InterruptedException e) {e.printStackTrace();}System.out.println(Thread.currentThread().getName() + "正在出售第" + tickets + "张票");tickets--;}}finally {lock.unlock();}}}}

package SellTicketPack02;public class SellTicketDemo {public static void main(String[] args){SellTicket st = new SellTicket();Thread t1 = new Thread(st,"窗口1");Thread t2 = new Thread(st,"窗口2");Thread t3 = new Thread(st,"窗口3");t1.start();t2.start();t3.start();}}