java - Java 8 的线程排序

Question

我有一个简单的程序，可以让两个线程交替打印增量数字。

所以，第一个线程打印:1

第二线程打印:2

第一个线程打印:3...等等

我可以使用“线程”类来执行此操作。但我想看看如何使用 Executor 类来执行此操作。

使用以下代码....执行程序类似乎不起作用。任何指针??

代码:

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

public class LocksPackagePractice {

    private int i = 0;

    ReentrantLock lock = new ReentrantLock();
    Condition condition = lock.newCondition();  

    Runnable r = () -> {
    for(int x = 0; x < 5; x++){
        printValue();
    }
    printValue(); 
};

    public static void main(String[] args) {

        new LocksPackagePractice().trigger();
    }

    void trigger(){
        ExecutorService service = Executors.newFixedThreadPool(2);
        service.execute(r);
    }

    void printValue(){

        lock.lock();

        try {

            i++;
            System.out.println(Thread.currentThread().getName() + " and value is = " + i);

            condition.signal();         
            condition.await();

        } catch(InterruptedException e){
            e.printStackTrace();
        }finally {
            lock.unlock();
        }

    }
}

Answer 1

对您的程序进行了一些更改。运行它并检查它是否解决了困惑。

public class LocksPackagePractice {
    private int i = 0;
    ReentrantLock lock = new ReentrantLock();
    Condition condition = lock.newCondition();
    Runnable r = () -> {
        printValue();
    };
    public static void main(String[] args) {
        new LocksPackagePractice().trigger();
    }
    void trigger() {
        ExecutorService service = Executors.newFixedThreadPool(2);
        service.submit(r);
        for (int i = 0; i < 5; i++) {
            service.execute(r);
        }
    }
    void printValue() {
        lock.lock();
        try {
            i++;
            System.out.println(Thread.currentThread().getName() + " and value is = " + i);
            condition.signal();
            condition.await();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }
}

这将为您提供以下输出

pool-1-thread-1 and value is = 1
pool-1-thread-2 and value is = 2
pool-1-thread-1 and value is = 3
pool-1-thread-2 and value is = 4
pool-1-thread-1 and value is = 5
pool-1-thread-2 and value is = 6