多线程编程(二)-Exchanger的使用

• Exchanger的介绍

  　　类Exchanger的功能可以使两个线程之间传输数据。

• 方法exchange()的使用

　　　　　

package com.wjg.unit;

import java.util.concurrent.Exchanger;

public class Run {
    public static void main(String[] args) {
        Exchanger<String> exchanger = new Exchanger<String>();
        Run run =new Run();
        ThreadA a = run.new ThreadA(exchanger);
        ThreadB b = run.new ThreadB(exchanger);
        a.start();
        b.start();
    }
    
    public class ThreadA extends Thread{
        
        private Exchanger<String> exchanger;

        public ThreadA(Exchanger<String> exchanger) {
            super();
            this.exchanger = exchanger;
        }

        @Override
        public void run() {
            try {
                String receive = exchanger.exchange("123");
                System.out.println("在线程A中获得线程B的值："+receive);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
    
public class ThreadB extends Thread{
        
        private Exchanger<String> exchanger;

        public ThreadB(Exchanger<String> exchanger) {
            super();
            this.exchanger = exchanger;
        }

        @Override
        public void run() {
            try {
                String receive = exchanger.exchange("456");
                System.out.println("在线程B中获得线程A的值："+receive);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

运行结果：
在线程A中获得线程B的值：456
在线程B中获得线程A的值：123

方法exchange(V x,long timeout,TimeUnit unit)的使用

此方法是指在指定的时间内没有其他线程获取数据，则出现超时异常。

package com.wjg.unit1;

import java.util.concurrent.Exchanger;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

public class Run2 {
    public static void main(String[] args) {
        Exchanger<String> exchanger = new Exchanger<String>();
        Run2 run =new Run2();
        ThreadA a = run.new ThreadA(exchanger);
        a.start();
    }
    
    public class ThreadA extends Thread{
　　        
        private Exchanger<String> exchanger;

        public ThreadA(Exchanger<String> exchanger) {
            super();
            this.exchanger = exchanger;
        }

        @Override
        public void run() {
            try {
                 //设置超时时间
                String receive = exchanger.exchange("123",5,TimeUnit.SECONDS);
                System.out.println("在线程A中获得线程B的值："+receive);
            } catch (InterruptedException e) {
                e.printStackTrace();
            } catch (TimeoutException e) {
                e.printStackTrace();
            }
        }
    }
}

执行结果：
java.util.concurrent.TimeoutException
    at java.util.concurrent.Exchanger.exchange(Exchanger.java:683)
    at com.wjg.unit1.Run2$ThreadA.run(Run2.java:27)