ThreadPoolTaskExecutor是什么

• 类名org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor
  从类名可以看出这是spring的线程池

• 再来看下init方法，其实底层就是ThreadPoolExecutor

    @Override
    protected ExecutorService initializeExecutor(
            ThreadFactory threadFactory, RejectedExecutionHandler rejectedExecutionHandler) {

        BlockingQueue<Runnable> queue = createQueue(this.queueCapacity);
        ThreadPoolExecutor executor  = new ThreadPoolExecutor(
                this.corePoolSize, this.maxPoolSize, this.keepAliveSeconds, TimeUnit.SECONDS,
                queue, threadFactory, rejectedExecutionHandler);
        if (this.allowCoreThreadTimeOut) {
            executor.allowCoreThreadTimeOut(true);
        }

        this.threadPoolExecutor = executor;
        return executor;
    }

ThreadPoolTaskExecutor解决什么问题

• ThreadPoolTaskExecutor是InitializingBean、DisposableBean的实现类，
  spring容器后会自动处理其初始化方法和注销方法，我们只需配置bean即可
• 线程池的单例问题，交给spring容器实现单例，不用自己实现单例

ThreadPoolTaskExecutor简介和用法

    @Bean
    public ThreadPoolTaskExecutor myTaskExecutor() {
        ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
        // 核心线程数
        taskExecutor.setCorePoolSize(5);
        // 最大线程数
        taskExecutor.setMaxPoolSize(15);
        // 队列大小 默认使用LinkedBlockingQueue
        taskExecutor.setQueueCapacity(100);
        // 线程最大空闲时间
        taskExecutor.setKeepAliveSeconds(300);
        // 拒绝策略 默认new ThreadPoolExecutor.AbortPolicy()
        taskExecutor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        // 线程名称前缀
        taskExecutor.setThreadNamePrefix("My-Task-Executor-");
        //交给spring托管的会自动初始化，因为实现了InitializingBean接口
        //taskExecutor.initialize();
        return taskExecutor;
    }

    @Autowired
    private ThreadPoolTaskExecutor myTaskExecutor;

    public void sendMsg() {
        myTaskExecutor.execute(new Runnable() {
            @Override
            public void run() {
                System.out.println("发送消息");
            }
        });
    }