线程池4种拒绝策略

ゝ一纸荒年。 2024-04-17 18:59 90阅读 0赞

**目录**

线程池

4种拒绝策略

Demo

调用者运行策略CallerRunsPolicy

运行结果

结论

中止策略AbortPolicy

运行结果

结论

忽然的顿悟

丢弃策略DiscardPolicy

运行结果

结论

弃老策略DiscardOldestPolicy

运行结果

结果

--------------------

# 线程池 #

线程池促发拒绝策略的过程：线程池创建核心线程数corePoolSize，当有更多线程过来，放到缓存队列workQueue，队列满了之后，大于最大线程数maximumPoolSize，最后促发拒绝策略。保存活着时间是指线程池里面的线程空闲的时间maximumPoolSize。

# 4种拒绝策略 #

CallerRunsPolicy，AbortPolicy，DiscardPolicy，DiscardOldestPolicy

# Demo #

import lombok.extern.slf4j.Slf4j;
    
    /**
     * Created on 2019/8/30.
     *
     * @author yangsen
     */
    @Slf4j
    public class TestRunnable implements Runnable {
        @Override
        public void run() {
            if ("main".equals(Thread.currentThread().getName())) {
                log.info("main线程出现次数:{}", ThreadTest.sum.incrementAndGet());
            }
            log.info("线程名称：{},正在运行", Thread.currentThread().getName());
        }
    }

import java.util.concurrent.LinkedBlockingDeque;
    import java.util.concurrent.ThreadPoolExecutor;
    import java.util.concurrent.TimeUnit;
    import java.util.concurrent.atomic.AtomicLong;
    
    /**
     * Created on 2019/8/30.
     *
     * @author yangsen
     */
    public class ThreadTest {
    
        static AtomicLong sum = new AtomicLong(0);
    
        public static void main(String[] args) throws InterruptedException {
            /**
             * 调用者运行策略CallerRunsPolicy
             */
            // ThreadPoolExecutor executor=new ThreadPoolExecutor(2,5,5, TimeUnit.SECONDS,new LinkedBlockingDeque<>(2),new ThreadPoolExecutor.CallerRunsPolicy());
    
            /**
             * 中止策略AbortPolicy
             */
            //ThreadPoolExecutor executor = new ThreadPoolExecutor(2, 5, 5, TimeUnit.SECONDS, new LinkedBlockingDeque<>(2), new ThreadPoolExecutor.AbortPolicy());
            /**
             * 丢弃策略DiscardPolicy
             */
            //ThreadPoolExecutor executor = new ThreadPoolExecutor(2, 5, 5, TimeUnit.SECONDS, new LinkedBlockingDeque<>(2), new ThreadPoolExecutor.DiscardPolicy());
            /**
             * 弃老策略DiscardOldestPolicy
             */
            ThreadPoolExecutor executor = new ThreadPoolExecutor(2, 5, 5, TimeUnit.SECONDS, new LinkedBlockingDeque<>(2), new ThreadPoolExecutor.DiscardOldestPolicy());
            for (int i = 0; i < 100; i++) {
                executor.execute(new TestRunnable());
            }
        }
    }

## 调用者运行策略CallerRunsPolicy ##

ThreadPoolExecutor executor=new ThreadPoolExecutor(2,5,5, TimeUnit.SECONDS,new LinkedBlockingDeque<>(2),new ThreadPoolExecutor.CallerRunsPolicy());

## 运行结果 ##

10:42:39.790 [pool-1-thread-5] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-5,正在运行
    10:42:39.790 [pool-1-thread-4] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-4,正在运行
    10:42:39.790 [pool-1-thread-3] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-3,正在运行
    10:42:39.795 [pool-1-thread-5] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-5,正在运行
    10:42:39.790 [pool-1-thread-2] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-2,正在运行
    10:42:39.790 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.790 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:1
    10:42:39.795 [pool-1-thread-4] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-4,正在运行
    10:42:39.795 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.795 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:2
    10:42:39.795 [pool-1-thread-3] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-3,正在运行
    10:42:39.795 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.795 [pool-1-thread-5] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-5,正在运行
    10:42:39.795 [pool-1-thread-2] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-2,正在运行
    10:42:39.795 [pool-1-thread-5] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-5,正在运行
    10:42:39.795 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:3
    10:42:39.795 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.795 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:4
    10:42:39.795 [pool-1-thread-4] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-4,正在运行
    10:42:39.795 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.795 [pool-1-thread-3] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-3,正在运行
    10:42:39.795 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:5
    10:42:39.795 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.795 [pool-1-thread-3] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-3,正在运行
    10:42:39.795 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:6
    10:42:39.795 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.795 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.795 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:7
    10:42:39.795 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.795 [pool-1-thread-2] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-2,正在运行
    10:42:39.795 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.795 [pool-1-thread-3] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-3,正在运行
    10:42:39.795 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.795 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:8
    10:42:39.795 [pool-1-thread-2] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-2,正在运行
    10:42:39.795 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.795 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.795 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:9
    10:42:39.795 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.795 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.795 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:10
    10:42:39.796 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.796 [pool-1-thread-5] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-5,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:11
    10:42:39.796 [pool-1-thread-5] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-5,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.796 [pool-1-thread-5] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-5,正在运行
    10:42:39.796 [pool-1-thread-5] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-5,正在运行
    10:42:39.796 [pool-1-thread-2] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-2,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:12
    10:42:39.796 [pool-1-thread-2] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-2,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.796 [pool-1-thread-4] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-4,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:13
    10:42:39.796 [pool-1-thread-2] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-2,正在运行
    10:42:39.796 [pool-1-thread-3] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-3,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:14
    10:42:39.796 [pool-1-thread-5] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-5,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.796 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:15
    10:42:39.796 [pool-1-thread-4] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-4,正在运行
    10:42:39.796 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:16
    10:42:39.796 [pool-1-thread-3] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-3,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.796 [pool-1-thread-5] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-5,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:17
    10:42:39.796 [pool-1-thread-5] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-5,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.796 [pool-1-thread-2] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-2,正在运行
    10:42:39.796 [pool-1-thread-4] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-4,正在运行
    10:42:39.796 [pool-1-thread-2] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-2,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:18
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:19
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:20
    10:42:39.796 [pool-1-thread-4] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-4,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.796 [pool-1-thread-5] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-5,正在运行
    10:42:39.796 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:21
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.796 [pool-1-thread-4] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-4,正在运行
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:22
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:23
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:24
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.797 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:25
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.797 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.797 [pool-1-thread-5] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-5,正在运行
    10:42:39.797 [pool-1-thread-3] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-3,正在运行
    10:42:39.797 [pool-1-thread-3] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-3,正在运行
    10:42:39.797 [pool-1-thread-4] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-4,正在运行
    10:42:39.797 [pool-1-thread-5] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-5,正在运行
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:26
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:27
    10:42:39.797 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.797 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:28
    10:42:39.797 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.797 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:29
    10:42:39.797 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:30
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.797 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:31
    10:42:39.797 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.797 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:32
    10:42:39.797 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.797 [pool-1-thread-3] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-3,正在运行
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行
    10:42:39.797 [pool-1-thread-4] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-4,正在运行
    10:42:39.797 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:42:39.797 [pool-1-thread-4] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-4,正在运行
    10:42:39.797 [pool-1-thread-2] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-2,正在运行
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - main线程出现次数:33
    10:42:39.797 [main] INFO com.example.demo.test.TestRunnable - 线程名称：main,正在运行

## 结论 ##

可以看到线程是不会中断的，在main线程调用，难怪叫调用者运行策略，main线程其中出现了33次。

# 中止策略AbortPolicy #

**默认策略**

ThreadPoolExecutor executor = new ThreadPoolExecutor(2, 5, 5, TimeUnit.SECONDS, new LinkedBlockingDeque<>(2), new ThreadPoolExecutor.AbortPolicy());

## 运行结果 ##

Exception in thread "main" java.util.concurrent.RejectedExecutionException: Task com.example.demo.test.TestRunnable@2cdf8d8a rejected from java.util.concurrent.ThreadPoolExecutor@30946e09[Running, pool size = 5, active threads = 5, queued tasks = 2, completed tasks = 0]
    	at java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2063)
    	at java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:830)
    	at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1379)
    	at com.example.demo.test.ThreadTest.main(ThreadTest.java:28)
    10:51:34.747 [pool-1-thread-2] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-2,正在运行
    10:51:34.747 [pool-1-thread-3] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-3,正在运行
    10:51:34.747 [pool-1-thread-5] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-5,正在运行
    10:51:34.748 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:51:34.747 [pool-1-thread-4] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-4,正在运行
    10:51:34.752 [pool-1-thread-5] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-5,正在运行
    10:51:34.752 [pool-1-thread-2] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-2,正在运行

## 结论 ##

由于创建的时候根本没有停顿，瞬间就爆了，线程也中断了。所以要处理好抛出的异常，进行下面的改造。

for (int i = 0; i < 100; i++) {
                try {
                    executor.execute(new TestRunnable());
                }catch (Exception e){
                    log.error("出现错误：{}",e.getMessage());
                }
            }

## 忽然的顿悟 ##

由于这个是默认策略，ExecutorService 的队列是无界的，所以当线程数提交很多时，会把整个队列塞满，导致cpu很高，所以一般使用ThreadPoolExecutor去创建线程池！！！nice

# 丢弃策略DiscardPolicy #

ThreadPoolExecutor executor = new ThreadPoolExecutor(2, 5, 5, TimeUnit.SECONDS, new LinkedBlockingDeque<>(2), new ThreadPoolExecutor.DiscardPolicy());

## 运行结果 ##

10:57:25.292 [pool-1-thread-2] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-2,正在运行
    10:57:25.296 [pool-1-thread-2] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-2,正在运行
    10:57:25.296 [pool-1-thread-2] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-2,正在运行
    10:57:25.309 [pool-1-thread-3] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-3,正在运行
    10:57:25.309 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    10:57:25.312 [pool-1-thread-4] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-4,正在运行
    10:57:25.316 [pool-1-thread-5] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-5,正在运行

## 结论 ##

也是由于没有停顿，瞬间爆了，然后把新加入的都剔除掉

# 弃老策略DiscardOldestPolicy #

ThreadPoolExecutor executor = new ThreadPoolExecutor(2, 5, 5, TimeUnit.SECONDS, new LinkedBlockingDeque<>(2), new ThreadPoolExecutor.DiscardOldestPolicy());

## 运行结果 ##

11:37:25.531 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    11:37:25.531 [pool-1-thread-4] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-4,正在运行
    11:37:25.535 [pool-1-thread-1] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-1,正在运行
    11:37:25.531 [pool-1-thread-2] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-2,正在运行
    11:37:25.531 [pool-1-thread-5] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-5,正在运行
    11:37:25.531 [pool-1-thread-3] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-3,正在运行
    11:37:25.535 [pool-1-thread-4] INFO com.example.demo.test.TestRunnable - 线程名称：pool-1-thread-4,正在运行

## 结果 ##

会把老的线程剔除。

可能会再出一篇ExecutorService的总结

# #