Java基礎複習：線程練習2

修改練習1賣票例子，先讓它網路延遲，出現問題，再解決問題。

 

1）同步代碼塊

class Ticket implements Runnable {private Integer num = 50;@Overridepublic void run() {for (int i = 0; i < 200; i++) {sale();}}private Object o = new Object();// 作為監聽對象/** * 賣票 */public void sale() {synchronized (o) {if (num > 0) {try {Thread.sleep(1);} catch (InterruptedException e) {e.printStackTrace();}System.out.println(Thread.currentThread().getName() + "賣出了第"+ num-- + "張票");}}}}public class TicketDemo {public static void main(String[] args) {Runnable target = new Ticket();new Thread(target, "A").start();new Thread(target, "B").start();new Thread(target, "C").start();}}

 

2）方法2：同步方法

 

class Ticket implements Runnable {private Integer num = 50;@Overridepublic void run() {for (int i = 0; i < 200; i++) {sale();}}/** * 賣票 */public synchronized void sale() {if (num > 0) {try {Thread.sleep(1);} catch (InterruptedException e) {e.printStackTrace();}System.out.println(Thread.currentThread().getName() + "賣出了第"+ num-- + "張票");}}}public class TicketDemo {public static void main(String[] args) {Runnable target = new Ticket();new Thread(target, "A").start();new Thread(target, "B").start();new Thread(target, "C").start();}}

3）可重新進入鎖

 

import java.util.concurrent.locks.ReentrantLock;class Ticket implements Runnable {private Integer num = 50;private ReentrantLock lock = new ReentrantLock();@Overridepublic void run() {for (int i = 0; i < 200; i++) {sale();}}/** * 賣票 */public void sale() {lock.lock();if (num > 0) {try {Thread.sleep(1);System.out.println(Thread.currentThread().getName() + "賣出了第" + num-- + "張票");} catch (Exception e) {e.printStackTrace();} finally {lock.unlock();}}}}public class TicketDemo {public static void main(String[] args) {Runnable target = new Ticket();new Thread(target, "A").start();new Thread(target, "B").start();new Thread(target, "C").start();}}