【Java記錄】try-with-resources的一個坑

##【Java記錄】try-with-resources的一個坑

今天處理 AsynchronousFileChannel 時候的一個問題，代碼以下：

public static void main(String[] args) throws Exception {

    String filePath = "/home/xe/git/osc/JavaNote/Lang/data/Test.java";
    ExecutorService executorService = Executors.newSingleThreadExecutor();
    Set<OpenOption> openOptions = new HashSet<>(Arrays.asList(new StandardOpenOption[]{StandardOpenOption.READ}));

    try (AsynchronousFileChannel asynchronousFileChannel = AsynchronousFileChannel.open(Paths.get(filePath), openOptions, executorService)) {
        ByteBuffer buffer = ByteBuffer.allocate(1024);
        asynchronousFileChannel.read(buffer, 0, buffer, new CompletionHandler<Integer, ByteBuffer>() {
            @Override
            public void completed(Integer result, ByteBuffer attachment) {
                System.out.println("completed,result = " + result);
                executorService.shutdown();
            }

            @Override
            public void failed(Throwable exc, ByteBuffer attachment) {
                System.out.println("failed");
                exc.printStackTrace();
                executorService.shutdown();
            }
        });
    } catch (Exception e) {
    }
}

一直提示：

java.nio.channels.AsynchronousCloseException

一直找不到問題的緣由，由於我並無顯式的去關閉 AsynchronousFileChannel，後來才發現，是被 try-with-resources 特性給關閉了，悲傷的故事。

因此，在異步調用中， 仍是謹慎的處理通告的關閉操做比較好。