java - 无法在另一个线程之后启动执行程序

Question

这个问题已经有答案了:

Running Thread by calling start() and run(), what is the difference? (7 个回答)

Second thread doesn't start in producer consumer example (1 个回答)

child thread blocks parent thread in java (1 个回答)

已关闭 5 年前。

当我运行下面的代码时，生产者 run() 方法启动并将随机数放入作业队列，但消费者 run() 方法从未运行。这里的主要问题是什么？

这是主类；

public static LinkedBlockingQueue<Integer> jobs = new LinkedBlockingQueue<>();

public static void main(){

    MessageProducer producer = new MessageProducer(jobs);
    Thread producerThread = new Thread(producer);
    producerThread.run();

    MessageConsumer consumer = new MessageConsumer(jobs);
    Executor executor = Executors.newFixedThreadPool(3);
    executor.execute(consumer);

}

制片人；

public class MessageProducer implements Runnable {

    public LinkedBlockingQueue<Integer> jobs;

    public MessageProducer(LinkedBlockingQueue<Integer> jobs){
        this.jobs = jobs;
    }

    @Override
    public void run() {
        while(true) {
            try {
                jobs.put((int) (Math.random() * 10));
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

消费者；

public class MessageConsumer implements Runnable{

    public LinkedBlockingQueue<Integer> jobs;

    public MessageConsumer(LinkedBlockingQueue<Integer> jobs) {
        this.jobs = jobs;
    }


    @Override
    public void run() {
        while(true) {
            System.out.println("Executing " + jobs.poll());
            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

Answer 1

不要调用Thread.run() 。它不会启动线程。它调用run()在您的情况下是无限循环的方法。
因此 JVM 停留在 producerThread.run();永远不会回来。

而是调用Thread.start()将负责调用 run()方法。

Thread.start() javadoc 确实指出:

Causes this thread to begin execution; the Java Virtual Machine calls the run method of this thread.