线程通信

Posted 2023-03-08 骑驴晒太阳

目前了解到的有三种情况
　　1.condition(await/signal)
　　2.object(wait/notify)
　　3.volatile

这里只对condition和object进行测试
================================================================================================================================

package com.meritdata.cloud.thirdsystemintegration.service;

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class TestCondition 
    private Lock lock = new ReentrantLock();
    private Condition condition1 = lock.newCondition();
    private Condition condition2 = lock.newCondition();
    private Condition condition3 = lock.newCondition();

    private int index = 1;


    public void test1() 
        lock.lock();
        try 
            while (index != 1) 
                condition1.await();
            
            index = 2;
            System.out.println(Thread.currentThread().getName());
            condition2.signal();
         catch (InterruptedException e) 
            throw new RuntimeException(e);
         finally 
            lock.unlock();
        
    

    public void test2() 
        lock.lock();
        try 
            while (index != 2) 
                condition2.await();
            
            index = 3;
            System.out.println(Thread.currentThread().getName());
            condition3.signal();
         catch (Exception e) 
            throw new RuntimeException(e);
         finally 
            lock.unlock();
        
    


    public void test3() 
        lock.lock();
        try 
            while (index != 3) 
                condition3.await();
            
            index = 1;
            System.out.println(Thread.currentThread().getName());
            condition1.signal();
         catch (InterruptedException e) 
            throw new RuntimeException(e);
         finally 
            lock.unlock();
        
    

    public static void main(String[] args) 

        TestCondition test = new TestCondition();

        Thread thread1 = new Thread(() -> 
            for (int i = 0; i < 3; i++) 
                test.test1();
            
        );
        Thread thread2 = new Thread(() -> 
            for (int i = 0; i < 3; i++) 
                test.test2();
            
        );
        Thread thread3 = new Thread(() -> 
            for (int i = 0; i < 3; i++) 
                test.test3();
                System.out.println("================================");
            
        );

        thread3.start();
        thread2.start();
        thread1.start();

    

=============================================================================================================

package com.meritdata.cloud.thirdsystemintegration.service;

import com.google.common.collect.Lists;
import org.springframework.util.CollectionUtils;

import java.util.List;

public class TestCondition 


    private Object lock = new Object();

    private List<Integer> list = Lists.newArrayListWithCapacity(2);

    public void take() 
        synchronized (lock) 
            while (CollectionUtils.isEmpty(list)) 
                try 
                    System.out.println(Thread.currentThread().getName()+"take wait...");
                    lock.wait();
                 catch (InterruptedException e) 
                    throw new RuntimeException(e);
                
            
            list.remove(list.get(0));
            System.out.println(Thread.currentThread().getName()+"put signal...,list size:"+list.size());
            lock.notify();
        
    

    public void put() 
        synchronized (lock) 
            while (list.size() >= 2) 
                try 
                    System.out.println(Thread.currentThread().getName()+"put wait...");
                    lock.wait();
                 catch (InterruptedException e) 
                    throw new RuntimeException(e);
                
            
            list.add(1);
            System.out.println(Thread.currentThread().getName()+"take signal...,list size:"+list.size());
            lock.notify();
        
    

    public static void main(String[] args) 
        TestCondition condition = new TestCondition();
        Thread thread1 = new Thread(() -> 
            for (int i = 0; i < 2; i++) 
                condition.take();
            
        );
        thread1.setName("take thread:");


        Thread thread2 = new Thread(() -> 
            for (int i = 0; i < 3; i++) 
                condition.put();
            
        );
        thread2.setName("put thread:");
        thread1.start();
        thread2.start();