java-多线程-waitnotify

1. 因为涉及到对象锁，Wait、Notify一定要在synchronized里面进行使用。
2. Wait必须暂定当前正在执行的线程,并释放资源锁,让其他线程可以有机会运行
3. notify/notifyall: 唤醒线程

• 共享变量

public class ShareEntity {    private String name;    // 线程通讯标识    private Boolean flag = false;    public ShareEntity() {    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public Boolean getFlag() {        return flag;    }    public void setFlag(Boolean flag) {        this.flag = flag;    }}

• 线程1（生产者）

public class CommunicationThread1 extends Thread{    private ShareEntity shareEntity;    public CommunicationThread1(ShareEntity shareEntity) {        this.shareEntity = shareEntity;    }    @Override    public void run() {        int num = 0;        while (true) {            synchronized (shareEntity) {                if (shareEntity.getFlag()) {                    try {                        shareEntity.wait();                    } catch (InterruptedException e) {                        e.printStackTrace();                    }                }                if (num % 2 == 0)                    shareEntity.setName("thread1-set-name-0");                else                    shareEntity.setName("thread1-set-name-1");                num++;                shareEntity.setFlag(true);                shareEntity.notify();            }        }    }}

• 线程2（消费者）

public class CommunicationThread2 extends Thread{    private ShareEntity shareEntity;    public CommunicationThread2(ShareEntity shareEntity) {        this.shareEntity = shareEntity;    }    @Override    public void run() {        while (true) {            synchronized (shareEntity) {                if (!shareEntity.getFlag()) {                    try {                        shareEntity.wait();                    } catch (InterruptedException e) {                        e.printStackTrace();                    }                }                System.out.println(shareEntity.getName());                shareEntity.setFlag(false);                shareEntity.notify();            }        }    }}

• 请求

@RequestMapping("test-communication")    public void testCommunication() {        ShareEntity shareEntity = new ShareEntity();        CommunicationThread1 thread1 = new CommunicationThread1(shareEntity);        CommunicationThread2 thread2 = new CommunicationThread2(shareEntity);        thread1.start();        thread2.start();    }

• 结果

thread1-set-name-0
thread1-set-name-1
thread1-set-name-0
thread1-set-name-1
thread1-set-name-0
thread1-set-name-1
thread1-set-name-0