code: public void init() {
          executor = new ThreadPoolExecutor(corePoolSize, maximumPoolSize, keepAliveTime, TimeUnit.MILLISECONDS,
              ThreadPoolUtils.buildQueue(queueSize), new NamedThreadFactory(threadPoolName));
          if (allowCoreThreadTimeOut) {
              executor.allowCoreThreadTimeOut(true);
          }
          if (prestartAllCoreThreads) {
              executor.prestartAllCoreThreads();
          }
      }
docs: 初始化线程池