java 線程池等待所有線程執行完畢

// 創建線程池
ExecutorService executorService = Executors.newFixedThreadPool(20);

// 提交線程任務

executorService.submit();

//不在接收新的任務
executorService.shutdown();
try {
// 等待所有線程執行完畢
    executorService.awaitTermination(Long.MAX_VALUE,TimeUnit.NANOSECONDS);
} catch (InterruptedException e) {
   log.error(e.getMessage());
}