wait, notify 使用清晰講解

時間 2019-11-17

標籤 wait notify 使用清晰講解欄目 Java 简体版

原文原文鏈接

一個廟裏，三個和尚，只有一個碗，三個和尚都要吃飯，因此每次吃飯的時候，三個和尚搶着碗吃。java

package interview.java.difference.l05;

public class WaitAndNotifyAndNotifyAll {

    static class Bowl{
        private String id;

        public String getId() {
            return id;
        }

        public void setId(String id) {
            this.id = id;
        }
        
    }
    
    static class Monk1Eat implements Runnable{
        private Bowl bowl;
        private String name;
        
        public Monk1Eat(Bowl bowl){
            this.bowl=bowl;
            name="monk1";
        }
        
        public String getName() {
            return name;
        }

        public void run() {
            while(true){
                System.out.println(this.getName()+" is eating with bowl"+bowl.getId());
            }        
        }
        
    }
    
    static class Monk2Eat implements Runnable{
        private Bowl bowl;
        private String name;
        
        public Monk2Eat(Bowl bowl){
            this.bowl=bowl;
            name="monk2";
        }
        
        public String getName() {
            return name;
        }

        public void run() {

            while(true){
                System.out.println(this.getName()+" is eating with bowl"+bowl.getId());
            }        
        }
        
    }
    
    static class Monk3Eat implements Runnable{
        private Bowl bowl;
        private String name;
        
        public Monk3Eat(Bowl bowl){
            this.bowl=bowl;
            name="monk3";
        }
        
        public String getName() {
            return name;
        }

        public void run() {
            while(true){
                System.out.println(this.getName()+" is eating with bowl"+bowl.getId());
            }        
        }
        
    }
    
    public static void main(String[] args) {
        Bowl bowl = new Bowl();
        bowl.setId("onlyOneBowl");
        Thread monk1=new Thread(new Monk1Eat(bowl));
        Thread monk2=new Thread(new Monk2Eat(bowl));
        Thread monk3=new Thread(new Monk3Eat(bowl));
        monk1.start();
        monk2.start();
        monk3.start();        
    }
}

View Code

以後三個和尚懂得互相謙讓了。每一個人吃5分鐘，換另外一我的吃，隨機換，這時候，停下吃的那個和尚等待，並把碗給另外一我的。注意，是鎖wait，而後鎖notify另外一我的。不是和尚wait而後notify，這樣會報出illegalmonitorstate的異常。ide

package interview.java.difference.l05;

public class WaitAndNotifyAndNotifyAll {

    static class Bowl{
        private String id;

        public String getId() {
            return id;
        }

        public void setId(String id) {
            this.id = id;
        }
        
    }
    
    static class Monk1Eat implements Runnable{
        private Bowl bowl;
        private String name;
        private long now;
        
        public Monk1Eat(Bowl bowl){
            this.bowl=bowl;
            name="monk1";
            now=System.currentTimeMillis();
        }
        
        public String getName() {
            return name;
        }

        public void run() {
            synchronized (bowl) {
                while(true){
                        try {
                            bowl.wait(3*1000);
                            bowl.notify();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    System.out.println(this.getName()+" is eating with bowl"+bowl.getId());
                    try {
                        System.out.println(this.getName()+" is digesting");
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }    
            }
                
        }
        
    }
    
    static class Monk2Eat implements Runnable{
        private Bowl bowl;
        private String name;
        private long now;
        
        public Monk2Eat(Bowl bowl){
            this.bowl=bowl;
            name="monk2";
            now=System.currentTimeMillis();
        }
        
        public String getName() {
            return name;
        }

        public void run() {
            synchronized (bowl) {
                while(true){
                        try {
                            bowl.wait(3*1000);
                            bowl.notify();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    System.out.println(this.getName()+" is eating with bowl"+bowl.getId());
                    try {
                        System.out.println(this.getName()+" is digesting");
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }    
            }
                
        }
        
    }
    
    static class Monk3Eat implements Runnable{
        private Bowl bowl;
        private String name;
        private long now;
        
        public Monk3Eat(Bowl bowl){
            this.bowl=bowl;
            name="monk3";
            now=System.currentTimeMillis();
        }
        
        public String getName() {
            return name;
        }

        public void run() {
            synchronized (bowl) {
                long now=System.currentTimeMillis();
                while(true){
                        try {
                            bowl.wait(3*1000);
                            bowl.notify();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    System.out.println(this.getName()+" is eating with bowl"+bowl.getId());
                    try {
                        System.out.println(this.getName()+" is digesting");
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }    
            }
                
        }
        
    }
    
    public static void main(String[] args) {
        Bowl bowl = new Bowl();
        bowl.setId("onlyOneBowl");
        Thread monk1=new Thread(new Monk1Eat(bowl));
        Thread monk2=new Thread(new Monk2Eat(bowl));
        Thread monk3=new Thread(new Monk3Eat(bowl));
        monk1.start();
        monk2.start();
        monk3.start();        
    }
}

使用線程去notify 和waitthis

代碼：spa

package interview.java.difference.l05;

public class WaitAndNotifyAndNotifyAll {

    static class Bowl{
        private String id;

        public String getId() {
            return id;
        }

        public void setId(String id) {
            this.id = id;
        }
        
    }
    
    static class Monk1Eat implements Runnable{
        private Bowl bowl;
        private String name;
        private long now;
        
        public Monk1Eat(Bowl bowl){
            this.bowl=bowl;
            name="monk1";
            now=System.currentTimeMillis();
        }
        
        public String getName() {
            return name;
        }

        public void run() {
            synchronized (bowl) {
                while(true){
                        try {
                            Thread.currentThread().wait(3*1000);
                            Thread.currentThread().notify();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    System.out.println(this.getName()+" is eating with bowl"+bowl.getId());
                    try {
                        System.out.println(this.getName()+" is digesting");
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }    
            }
                
        }
        
    }
    
    static class Monk2Eat implements Runnable{
        private Bowl bowl;
        private String name;
        private long now;
        
        public Monk2Eat(Bowl bowl){
            this.bowl=bowl;
            name="monk2";
            now=System.currentTimeMillis();
        }
        
        public String getName() {
            return name;
        }

        public void run() {
            synchronized (bowl) {
                while(true){
                        try {
                            Thread.currentThread().wait(3*1000);
                            Thread.currentThread().notify();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    System.out.println(this.getName()+" is eating with bowl"+bowl.getId());
                    try {
                        System.out.println(this.getName()+" is digesting");
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }    
            }
                
        }
        
    }
    
    static class Monk3Eat implements Runnable{
        private Bowl bowl;
        private String name;
        private long now;
        
        public Monk3Eat(Bowl bowl){
            this.bowl=bowl;
            name="monk3";
            now=System.currentTimeMillis();
        }
        
        public String getName() {
            return name;
        }

        public void run() {
            synchronized (bowl) {
                long now=System.currentTimeMillis();
                while(true){
                        try {
                            Thread.currentThread().wait(3*1000);
                            Thread.currentThread().notify();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    System.out.println(this.getName()+" is eating with bowl"+bowl.getId());
                    try {
                        System.out.println(this.getName()+" is digesting");
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }    
            }
                
        }
        
    }
    
    public static void main(String[] args) {
        Bowl bowl = new Bowl();
        bowl.setId("onlyOneBowl");
        Thread monk1=new Thread(new Monk1Eat(bowl));
        Thread monk2=new Thread(new Monk2Eat(bowl));
        Thread monk3=new Thread(new Monk3Eat(bowl));
        monk1.start();
        monk2.start();
        monk3.start();        
    }
}

報錯：線程

Exception in thread "Thread-0" Exception in thread "Thread-2" Exception in thread "Thread-1" java.lang.IllegalMonitorStateException
    at java.lang.Object.wait(Native Method)
    at interview.java.difference.l05.WaitAndNotifyAndNotifyAll$Monk1Eat.run(WaitAndNotifyAndNotifyAll.java:37)
    at java.lang.Thread.run(Unknown Source)
java.lang.IllegalMonitorStateException
    at java.lang.Object.wait(Native Method)
    at interview.java.difference.l05.WaitAndNotifyAndNotifyAll$Monk2Eat.run(WaitAndNotifyAndNotifyAll.java:76)
    at java.lang.Thread.run(Unknown Source)
java.lang.IllegalMonitorStateException
    at java.lang.Object.wait(Native Method)
    at interview.java.difference.l05.WaitAndNotifyAndNotifyAll$Monk3Eat.run(WaitAndNotifyAndNotifyAll.java:116)
    at java.lang.Thread.run(Unknown Source)

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