java线程池RejectedExecutionException出现的三种典型场景：Terminated,Shutting down,Running

最新推荐文章于 2025-04-18 20:33:22 发布

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最新推荐文章于 2025-04-18 20:33:22 发布

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文章标签： java

本文链接：https://blog.youkuaiyun.com/hongqiutiandi163/article/details/108217676

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本文深入探讨了Java中线程池的各种状态，包括TERMINATED、SHUTDOWN和RUNNING，解析了每种状态下线程池的行为特征及可能出现的问题，如RejectedExecutionException异常的抛出。通过具体代码示例，展示了不同状态下的线程池如何处理任务提交。

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TERMINATED

java.util.concurrent.RejectedExecutionException: Task java.util.concurrent.FutureTask@2cd3e0cd rejected from java.util.concurrent.ThreadPoolExecutor@77da21eb[Terminated, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 0]

package com.company;

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.LinkedTransferQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class ExecutorDemo {
    public static void main(String[] args) {
    ExecutorService pool =
        new ThreadPoolExecutor(2, 2, 10000, TimeUnit.MILLISECONDS, new LinkedTransferQueue<>());

        pool.shutdown();

        for(int i=0;i<10;i++) {
            pool.submit(new Task());
        }
    }

    private static class Task implements Callable<Integer> {
        public Integer call() {
            try {
                System.out.println(Thread.currentThread().getName() + " running...");
                Thread.sleep(10000l);
            } catch(InterruptedException e) {
                e.printStackTrace();
            }
            return 1;
        }
    }
}

SHUTDOWN

java.util.concurrent.RejectedExecutionException: Task java.util.concurrent.FutureTask@2cd3e0cd rejected from java.util.concurrent.ThreadPoolExecutor@77da21eb[Shutting down, pool size = 2, active threads = 2, queued tasks = 8, completed tasks = 0]

package com.company;

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.LinkedTransferQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class ExecutorDemo {
    public static void main(String[] args) {
    ExecutorService pool =
        new ThreadPoolExecutor(2, 2, 10000, TimeUnit.MILLISECONDS, new LinkedTransferQueue<>());

        for (int i = 0; i < 10; i++) {
            pool.submit(new Task());
        }

        pool.shutdown();

        for(int i=0;i<10;i++) {
            pool.submit(new Task());
        }
    }

    private static class Task implements Callable<Integer> {
        public Integer call() {
            try {
                System.out.println(Thread.currentThread().getName() + " running...");
                Thread.sleep(10000l);
            } catch(InterruptedException e) {
                e.printStackTrace();
            }
            return 1;
        }
    }
}

RUNNING

java.util.concurrent.RejectedExecutionException: Task java.util.concurrent.FutureTask@2cd3e0cd rejected from java.util.concurrent.ThreadPoolExecutor@77da21eb[Running, pool size = 2, active threads = 2, queued tasks = 0, completed tasks = 0]

package com.company;

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.SynchronousQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class ExecutorDemo {
    public static void main(String[] args) {
    ExecutorService pool =
        new ThreadPoolExecutor(2, 2, 10000, TimeUnit.MILLISECONDS, new SynchronousQueue<>());

        for (int i = 0; i < 10; i++) {
            pool.submit(new Task());
        }
    }

    private static class Task implements Callable<Integer> {
        public Integer call() {
            try {
                System.out.println(Thread.currentThread().getName() + " running...");
                Thread.sleep(10000l);
            } catch(InterruptedException e) {
                e.printStackTrace();
            }
            return 1;
        }
    }
}