java - 线程池任务执行器

Question

为什么 Spring 的 ThreadPoolTask​​Executor 会继续创建达到 Core Size 值的线程，无论现有线程是否空闲!

    ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
    executor.setCorePoolSize(300);
    executor.setMaxPoolSize(500);
    executor.setQueueCapacity(5000);
    executor.setThreadNamePrefix("AsyncTask-");
    executor.initialize();

我一个一个地发出请求，它不断增加线程数，直到达到 300。我的问题是，如果现有线程空闲，为什么它不使用空闲线程？一旦达到核心池大小，无论如何都只能使用池中的线程。

Answer 1

根据 java 文档，Spring 在这方面的工作较少 here

When a new task is submitted in method execute(Runnable), and fewer than corePoolSize threads are running, a new thread is created to handle the request, even if other worker threads are idle. If there are more than corePoolSize but less than maximumPoolSize threads running , a new thread will be created only if the queue is full