我有一个集成流程，该流程扫描文件以进行处理。由于可能有多个处理器扫描同一目录，因此我添加了“ .nioLocker（）”以防止来自其他JVM的处理器处理该文件。
这是流程配置：
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，即使当我调用BufferedReader.readLine时运行一个处理器，我也会得到一个异常，指出文件已锁定
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)
我试图通过调用释放锁
private NioFileLocker fileLocker = new NioFileLocker();
fileLocker.unlock(file);
但这不起作用！ （我怀疑是因为它是从与储物柜不同的线程中调用的，但我不确定）
获取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来确保锁定文件的线程与从其文件通道读取的线程相同。为此，我使用了直接通道。 （之前，传递给fileSplitter的消息是通过QueueChannel进行的，它将在另一个线程上执行send（））。还是我得到错误
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)
FileSplitter.java中的代码：
@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;
}
最佳答案
使用java.nio.channels.FileLock时，只能通过与该锁关联的FileChannel或InputStream来访问文件内容：
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。因此，您应该在代码中使用如下代码：
new DirectFieldAccessor(this.nioFileLocker).getPropertyValue("lockCache");
并将其转换为
Map<File, FileLock>以便能够为该文件创建一个FileLock。同时，请在此问题上提出一个JIRA。这个NioFileLocker引起很多问题。应该以某种方式修改。谢谢