线程池创建规范（摘自阿里java开发手册）

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(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);