Exchanger进行两个线程之间的数据交互

使用Exchanger进行两个线程之间的数据交互案例：

package com.dwz.utils;

import java.util.concurrent.Exchanger;

public class ExchangerExample1 {
    public static void main(String[] args) {
        Exchanger<String> exchanger = new Exchanger<String>();
        
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    String result = exchanger.exchange("I am from T-A.");
                    System.out.println("aaaaaaa");
                    System.out.println(Thread.currentThread().getName() + " Get value [" + result + "]");
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName() + "end.");
            }
        }, "==A==").start();
        
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    String result = exchanger.exchange("I am from T-B.");
                    Thread.sleep(10);
                    System.out.println("BBBBBBBBB");
                    System.out.println(Thread.currentThread().getName() + " Get value [" + result + "]");
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName() + "end.");
            }
        }, "==B==").start();
    }
}

测试结果：

aaaaaaa
==A== Get value [I am from T-B.]
==A==end.
BBBBBBBBB
==B== Get value [I am from T-A.]
==B==end.

验证A、B线程交换的数据都是同一份，并不是数据对象的复制

package com.dwz.utils;

import java.util.concurrent.Exchanger;
/**
 *    A、B线程交换的数据都是同一个，并不是对象的复制
 */
public class ExchangerExample2 {
    
    public static void main(String[] args) {
        Exchanger<Object> exchanger = new Exchanger<Object>();
        
        new Thread() {
            public void run() {
                Object aobj = new Object();
                System.out.println("A will send the object " + aobj);
                try {
                    Object robj = exchanger.exchange(aobj);
                    System.out.println("A received the object" + robj);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            };
        }.start();
        
        new Thread() {
            public void run() {
                Object bobj = new Object();
                System.out.println("B will send the object " + bobj);
                try {
                    Object robj = exchanger.exchange(bobj);
                    System.out.println("B received the object" + robj);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            };
        }.start();
    }
}

测试结果：

A will send the object java.lang.Object@5512a485
B will send the object java.lang.Object@28ec7f99
B received the objectjava.lang.Object@5512a485
A received the objectjava.lang.Object@28ec7f99

模拟一个A、B线程不断交换数据的场景

package com.dwz.utils;

import java.util.concurrent.Exchanger;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;
/**
 *    模拟一个A、B线程不断交换数据的场景
 */
public class ExchangerExample3 {
    public static void main(String[] args) {
        Exchanger<Integer> exchanger = new Exchanger<Integer>();
        
        new Thread() {
            public void run() {
                AtomicReference<Integer> value = new AtomicReference<Integer>(1);
                try {
                    while(true) {
                        value.set(exchanger.exchange(value.get()));
                        System.out.println("Thread A has value:" + value.get());
                        TimeUnit.SECONDS.sleep(3);
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            };
        }.start();
        
        new Thread() {
            public void run() {
                AtomicReference<Integer> value = new AtomicReference<Integer>(2);
                try {
                    while(true) {
                        value.set(exchanger.exchange(value.get()));
                        System.out.println("Thread B has value:" + value.get());
                        TimeUnit.SECONDS.sleep(2);
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            };
        }.start();
    }
}

测试结果：

Thread B has value:1
Thread A has value:2
Thread A has value:1
Thread B has value:2