wait notify

@Slf4j(topic = "c.TestWaitNotify")
public class TestWaitNotify {
    static final Object lock = new Object();
    public static void main(String[] args) throws InterruptedException {
        new Thread(()->{
            log.info("执行。。。。");
            synchronized (lock){
                try {
                    lock.wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        },"t1").start();
        new Thread(()->{
            log.info("执行。。。");
            synchronized (lock){
                try {
                    lock.wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        },"t2").start();
        TimeUnit.SECONDS.sleep(2);
        log.info("main thread 唤醒其他线程");
        synchronized (lock){
            lock.notify();// 唤醒t1和t2线程中其中一个
//            lock.notifyAll();// 唤醒所有synchronized wait 的线程
        }
    }
}

@Slf4j
public class TestCorrectPostureStep1 {
    static final Object room = new Object();
    static boolean hasCigarette = false;
    static boolean hasTakeout = false;
    public static void main(String[] args) {
        new Thread(()->{
            synchronized (room){
                if (!hasCigarette){
                    try {
                        log.info("没有烟，我要等一会才能工作");
                        room.wait();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
                if (hasCigarette){
                    log.debug("有烟，可以干活了");
                }
            }
        },"t1").start();
        for (int i = 0;i<5;i++){
            new Thread(()->{
                synchronized (room){
                    try {
                        Thread.sleep(2_000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    log.debug("开始干活了");
                }
            },"其他人"+i).start();
        }
        try {
            Thread.sleep(1_000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        new Thread(()->{
            synchronized (room) {
                hasCigarette = true;
                room.notify();
            }
        },"松烟的").start();
    }
}

虚假唤醒

package org.example.jvm;
import lombok.extern.slf4j.Slf4j;
import java.util.concurrent.TimeUnit;
/**
 * @author huskyui
 */
@Slf4j
public class TestCorrectPostureStep3 {
    final static Object lock = new Object();
    static boolean hasCigarette = false;
    static boolean hasTakeout = false;
    public static void main(String[] args) throws InterruptedException {
        new Thread(()->{
            synchronized (lock){
                log.info("有外卖吗 {}",hasTakeout);
                try{
                    lock.wait();
                }catch (Exception e){
                    e.printStackTrace();
                }
                log.info("有外卖没 {}",hasTakeout);
                if (hasTakeout){
                    log.debug("可以干活了。有外卖了");
                }else{
                    log.info("没干成活。。。");
                }
            }
        },"小女").start();
        new Thread(()->{
            synchronized (lock){
                log.info("有烟吗 {}",hasCigarette);
                try{
                    lock.wait();
                }catch (Exception e){
                    e.printStackTrace();
                }
                log.info("有烟没 {}",hasCigarette);
                if (hasCigarette){
                    log.debug("可以干活了。有烟了");
                }else{
                    log.info("没干成活。。。");
                }
            }
        },"小南").start();
        TimeUnit.SECONDS.sleep(2);
        new Thread(()->{
            synchronized (lock){
                hasCigarette = true;
                lock.notifyAll();
            }
        }).start();
    }
    public final void dos(){
    }
}

使用while，可以防止虚假唤醒

package org.example.jvm;
import lombok.extern.slf4j.Slf4j;
import java.util.concurrent.TimeUnit;
/**
 * @author huskyui
 */
@Slf4j
public class TestCorrectPostureStep3 {
    final static Object lock = new Object();
    static boolean hasCigarette = false;
    static boolean hasTakeout = false;
    public static void main(String[] args) throws InterruptedException {
        new Thread(() -> {
            synchronized (lock) {
                log.info("有外卖吗 {}", hasTakeout);
                while (!hasTakeout) {
                    log.info("没有外卖先歇会");
                    try {
                        lock.wait();
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
                log.info("有外卖没 {}", hasTakeout);
                if (hasTakeout) {
                    log.debug("可以干活了。有外卖了");
                } else {
                    log.info("没干成活。。。");
                }
            }
        }, "小女").start();
        new Thread(() -> {
            synchronized (lock) {
                log.info("有烟吗 {}", hasCigarette);
                while (!hasCigarette) {
                    log.info("没烟先歇会");
                    try {
                        lock.wait();
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
                log.info("有烟没 {}", hasCigarette);
                if (hasCigarette) {
                    log.debug("可以干活了。有烟了");
                } else {
                    log.info("没干成活。。。");
                }
            }
        }, "小南").start();
        TimeUnit.SECONDS.sleep(2);
        new Thread(() -> {
            synchronized (lock) {
                hasCigarette = true;
                lock.notifyAll();
            }
        }).start();
    }
}