private static final ScheduledExecutorService executorService = Executors.newScheduledThreadPool(1);我这样定义了线程池 然后执行到public void startReconnectTask() { executorService.schedule(() -> { if (!this.session.isOpen()) { logger.info("尝试重新连接..."); connectWs(remoteUrl); } }, RECONNECT_INTERVAL, TimeUnit.MILLISECONDS); } 这个方法 报错了Caused by: java.util.concurrent.RejectedExecutionException: Task java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask@1e67d4c6 rejected from java.util.concurrent.ScheduledThreadPoolExecutor@2617d56e[Terminated, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 5] at java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2063) at java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:830) at java.util.concurrent.ScheduledThreadPoolExecutor.delayedExecute(ScheduledThreadPoolExecutor.java:326) at java.util.concurrent.ScheduledThreadPoolExecutor.schedule(ScheduledThreadPoolExecutor.java:533) at com.fld.client.websocket.PiWsClient.startReconnectTask(PiWsClient.java:88) at com.fld.client.websocket.PiWsClient.onClose(PiWsClient.java:54) ... 22 more 分析一下什么原因 然后优化一点代码

这个错误是因为线程池已经被关闭，不能再进行任务调度，所以会抛出 `RejectedExecutionException` 异常。

可以在调用 `executorService.shutdown()` 方法关闭线程池后，再调用 `executorService.awaitTermination()` 方法等待线程池中的任务执行完毕，最后再尝试执行任务。修改后的代码如下：

// 关闭线程池
executorService.shutdown();
try {
    // 等待线程池中的任务执行完成
    if (!executorService.awaitTermination(60, TimeUnit.SECONDS)) {
        // 超时后仍有任务未执行完，强制关闭线程池
        executorService.shutdownNow();
    }
} catch (InterruptedException e) {
    // 线程被中断
    executorService.shutdownNow();
    Thread.currentThread().interrupt();
}

// 新建线程池
ScheduledExecutorService newExecutorService = Executors.newScheduledThreadPool(1);
// 执行任务
newExecutorService.schedule(() -> {
    if (!this.session.isOpen()) {
        logger.info("尝试重新连接...");
        connectWs(remoteUrl);
    }
}, RECONNECT_INTERVAL, TimeUnit.MILLISECONDS);

这样就可以在关闭线程池后重新新建线程池，并执行任务。同时，加入了等待线程池中任务执行完成的逻辑，保证不会存在线程池未关闭完毕的情况。