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如何调整scheduleatfixedrate的优先级

小樊
82
2024-09-02 22:57:53
栏目: 编程语言

ScheduledExecutorService 本身并不提供直接设置任务优先级的方法

以下是一个使用 PriorityBlockingQueue 实现的示例:

  1. 首先,创建一个自定义的 Runnable 类,其中包含一个表示优先级的字段:
public class PriorityRunnable implements Runnable, Comparable<PriorityRunnable> {
    private int priority;
    private Runnable task;

    public PriorityRunnable(int priority, Runnable task) {
        this.priority = priority;
        this.task = task;
    }

    @Override
    public void run() {
        task.run();
    }

    @Override
    public int compareTo(PriorityRunnable other) {
        return Integer.compare(other.priority, this.priority);
    }
}
  1. 然后,创建一个 PriorityBlockingQueue 实例,并将其传递给 ThreadPoolExecutor
import java.util.concurrent.*;

public class PriorityScheduler {
    public static void main(String[] args) {
        int corePoolSize = 4;
        PriorityBlockingQueue<Runnable> queue = new PriorityBlockingQueue<>();
        ThreadPoolExecutor executor = new ThreadPoolExecutor(corePoolSize, corePoolSize, 0L, TimeUnit.MILLISECONDS, queue);

        // 提交任务
        executor.submit(new PriorityRunnable(1, () -> System.out.println("Task with priority 1")));
        executor.submit(new PriorityRunnable(3, () -> System.out.println("Task with priority 3")));
        executor.submit(new PriorityRunnable(2, () -> System.out.println("Task with priority 2")));

        executor.shutdown();
    }
}

在这个示例中,我们创建了一个具有 4 个核心线程的线程池。当提交新任务时,它们将根据优先级顺序执行。请注意,这种方法可能会导致线程饥饿,因为高优先级任务可能会持续占用线程,从而阻止低优先级任务的执行。为了避免这种情况,可以考虑使用更复杂的调度策略,例如基于时间片轮转的调度。

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