java - 如何重启线程？

Question

它是一个 RMI 服务器对象，可能会运行很多 sethumanActivity()，我如何确保在新的 changeToFalse 运行之前停止或暂停先前的 changeToFalse 线程？ t。中断 ?

基本上当调用 sethumanActivity() 时，humanActivity 将被设置为 true ，但将运行一个线程将其设置回 false。但是我在考虑如何在调用另一个 sethumanActivity() 时禁用或终止线程？

public class VitaminDEngine implements VitaminD {

    public boolean humanActivity = false;
    changeToFalse cf = new changeToFalse();
    Thread t = new Thread(cf);


    private class changeToFalse implements Runnable{

        @Override
        public void run() {
            try {
                Thread.sleep(4000);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            humanActivity = false;
        }

    }

    @Override
    public void sethumanActivity() throws RemoteException {
        // TODO Auto-generated method stub
        humanActivity = true;
        t.start();
    }

    public boolean gethumanActivity() throws RemoteException {
        // TODO Auto-generated method stub
        return humanActivity;
    }

}

在 SOer 的帮助下编辑

package smartOfficeJava;

import java.rmi.RemoteException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class VitaminDEngine implements VitaminD {

    public volatile boolean humanActivity = false;
    changeToFalse cf = new changeToFalse();
    ExecutorService service = Executors.newSingleThreadExecutor();


    private class changeToFalse implements Runnable{

        @Override
        public void run() {
            try {
                Thread.sleep(4000);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            humanActivity = false;
        }

    }

    @Override
    public synchronized  void sethumanActivity() throws RemoteException {
        humanActivity = true;
        service.submit(cf);
    }

    public synchronized  boolean gethumanActivity() throws RemoteException {
        return humanActivity;
    }

}

Answer 1

使用 ExecutorService。 ExecutorService 将创建一个线程，您可以根据需要多次向它们提交可运行对象。

ExecutorService service = Executors.newSingleThreadExecutor();

然后在你的代码中

@Override
public void sethumanActivity() throws RemoteException {
    // TODO Auto-generated method stub
    humanActivity = true;
   service.submit(cf);
}

另外，为了正确起见，您正在不安全地写入 humanActivity 字段。存在过时读取的可能性。有很多文章谈论可见性，您可以查看here .