读取时发生java Spring集成nioLocker异常

Question

我有一个集成流程，可以扫描文件进行处理。由于可能有多个处理器扫描同一个目录，我添加了“.nioloker（）”以防止来自其他JVM的处理器处理该文件

以下是流程配置：

IntegrationFlows.from( // Scan files from input dir
                    s -> s.file(new File(fileInputDir))
                            .preventDuplicates(true)
                            .nioLocker()
                            .regexFilter("(.)*\\.[xX][mM][lL]|(.)+\\.[dD][nN][eE]"),        // to match any case of the letters XML
                    p -> p.poller(Pollers.fixedRate(filePollerInterval)
                            .taskExecutor(new ScheduledThreadPoolExecutor(filePoolSize))
                    )

现在的问题是，当我调用BufferedReader时，即使只有一个处理器在运行。readLine，我收到一个异常，文件被锁定

java.io.IOException: The process cannot access the file because another process has locked a portion of the file
    at java.io.FileInputStream.readBytes(Native Method)
    at java.io.FileInputStream.read(FileInputStream.java:255)
    at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:284)
    at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:326)
    at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:178)
    at java.io.InputStreamReader.read(InputStreamReader.java:184)
    at java.io.BufferedReader.fill(BufferedReader.java:161)
    at java.io.BufferedReader.readLine(BufferedReader.java:324)
    at java.io.BufferedReader.readLine(BufferedReader.java:389)

我打电话试图打开锁

 private NioFileLocker fileLocker = new NioFileLocker();
 fileLocker.unlock(file);

但这行不通！（我怀疑是因为它是从不同于储物柜的线程调用的，但我不确定）

获得锁的正确方法是什么？有没有更好的方法来确保只有一个处理器可以访问资源

------------------------------编辑---------------------------------

因此，我采取了额外的步骤，以确保锁定该文件的线程与从其文件通道读取的线程相同。为此，我使用了直接渠道。（之前，传递给FileSpliter的消息是通过队列通道传递的，队列通道将在另一个线程上执行send（）。但我还是犯了错误

2017-07-21 11:22:03.316  INFO 336488 --- [           main] c.f.e.m.i.MailerInboundApplication       : Started MailerInboundApplication in 13.541 seconds (JVM running for 14.419)
2017-07-21 11:22:09.946  INFO 336488 --- [ask-scheduler-5] o.s.i.file.FileReadingMessageSource      : Created message: [GenericMessage [payload=input\EMAIL92770.9352177.20170617.xml, headers={id=5dba6d62-b0a5-508e-48a9-cfddfa3b331f, timestamp=1500654129946}]]

2017-07-21 11:22:09.962 DEBUG 336488 --- [ask-scheduler-5] c.f.edd.mailer.inbound.core.FileRouter   : fileRouter received message: GenericMessage [payload=input\EMAIL92770.9352177.20170617.xml, headers={CORRELATION_ID=92770.9352177.20170617, id=32a8846d-5425-0b
ee-657e-8767e1fb6105, timestamp=1500654129962}]
2017-07-21 11:22:09.962 DEBUG 336488 --- [ask-scheduler-5] c.f.e.mailer.inbound.core.FileSplitter   : fileSplitter received message: GenericMessage [payload=input\EMAIL92770.9352177.20170617.xml, headers={CORRELATION_ID=92770.9352177.20170617, id=32a8846d-5425-
0bee-657e-8767e1fb6105, timestamp=1500654129962}]

java.io.IOException: The process cannot access the file because another process has locked a portion of the file
        at sun.nio.ch.FileDispatcherImpl.read0(Native Method)
        at sun.nio.ch.FileDispatcherImpl.read(FileDispatcherImpl.java:61)
        at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:223)
        at sun.nio.ch.IOUtil.read(IOUtil.java:197)
        at sun.nio.ch.FileChannelImpl.read(FileChannelImpl.java:159)
        at com.fiserv.edd.mailer.inbound.core.FileSplitter.splitMessage(FileSplitter.java:93)

FileSpliter上的代码。爪哇：

    @Override
protected Object splitMessage(Message<?> message) {
    String correlationId = (String) message.getHeaders().get("CORRELATION_ID"); //Save the correlation ID so we can use it to send the DNE/CLP file later
    File file = (File) message.getPayload();
    String inputFileName = file.getName();


    log.info(LogEvent.getBuilder().withMessageId(inputFileName)
            .withMessage("Processing file: " + inputFileName).build());

    long startTime = System.currentTimeMillis();
    Optional<InputHeader> inputHeader = Optional.empty();// headerParser.parse(file);

    ParsingReport pr = new ParsingReport(inputFileName);
    try (RandomAccessFile lfs = new RandomAccessFile(file.getAbsolutePath(), "rw")){
        FileChannel fc = lfs.getChannel();
        byte[] bytes = new byte[1024];
        fc.read(ByteBuffer.wrap(bytes));
        System.out.println(new String(bytes));

    } catch (FileNotFoundException e) {
            e.printStackTrace();
    } catch (IOException e) {
            e.printStackTrace();
    }
    return Collections.EMPTY_LIST;
}

Answer 1

当我们使用java.nio.channels.FileLock时，我们只能通过与该锁关联的FileChannel或InputStream访问文件内容：

FileInputStream in = new FileInputStream(file);
try {
    java.nio.channels.FileLock lock = in.getChannel().lock();
    try {
        Reader reader = new InputStreamReader(in, charset);
        ...
    } finally {
        lock.release();
    }
} finally {
    in.close();
} 

NioFileLocker不允许轻易访问FileLock。 所以，你应该在你的代码中使用这样的东西：

 new DirectFieldAccessor(this.nioFileLocker).getPropertyValue("lockCac‌​he");

并将其转换到Map<File, FileLock>中，以获得为该文件创建的FileLock

同时，请就此事提出意见。这个NioFileLocker会导致很多问题。应该以某种方式进行修改。谢谢