线程池不允许使用Executors去创建,而是通过ThreadPool

已有 1009人阅读此文 - - JAVA


线程池不允许使用Executors去创建,而是通过ThreadPoolExecutor的方式,这样的处理方式让写的同学更加明确线程池的运行规则,规避资源耗尽的风险。 说明:Executors各个方法的弊端:

1)newFixedThreadPool和newSingleThreadExecutor:

  主要问题是堆积的请求处理队列可能会耗费非常大的内存,甚至OOM。

2)newCachedThreadPool和newScheduledThreadPool:

  主要问题是线程数最大数是Integer.MAX_VALUE,可能会创建数量非常多的线程,甚至OOM。

            

Positive example 1:

    //org.apache.commons.lang3.concurrent.BasicThreadFactory

    ScheduledExecutorService executorService = new ScheduledThreadPoolExecutor(1,

        new BasicThreadFactory.Builder().namingPattern("example-schedule-pool-%d").daemon(true).build());

       

        

            

Positive example 2:

    ThreadFactory namedThreadFactory = new ThreadFactoryBuilder()

        .setNameFormat("demo-pool-%d").build();


    //Common Thread Pool

    ExecutorService pool = new ThreadPoolExecutor(5, 200,

        0L, TimeUnit.MILLISECONDS,

        new LinkedBlockingQueue<Runnable>(1024), namedThreadFactory, new ThreadPoolExecutor.AbortPolicy());


    pool.execute(()-> System.out.println(Thread.currentThread().getName()));

    pool.shutdown();//gracefully shutdown

       

        

            

Positive example 3:

    <bean id="userThreadPool"

        class="org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor">

        <property name="corePoolSize" value="10" />

        <property name="maxPoolSize" value="100" />

        <property name="queueCapacity" value="2000" />


    <property name="threadFactory" value= threadFactory />

        <property name="rejectedExecutionHandler">

            <ref local="rejectedExecutionHandler" />

        </property>

    </bean>

    //in code

    userThreadPool.execute(thread);

       

        


期待你一针见血的评论,Come on!