很难为我的问题取一个好的标题，但如下所示。首先，我在 Windows 上执行此操作，它也可能在 linux 机器上使用，因此我需要修复才能在两个系统上工作。我正在监视新文件的目录。我基本上是查看目录的文件并一遍又一遍地比较它们，然后只处理新文件。问题是我不断收到错误消息，在我尝试处理之前文件未完成写入。

public class LiveDetectionsProvider extends DetectionsProvider {
protected LiveDetectionsProvider.MonitorDirectory monitorDirectory = null;
protected TimeModel timeModel = null;
private ArrayList<String> loaded = new ArrayList();
private File topLayerFolder = null;
public LiveDetectionsProvider(String directory, String id) {
    super(directory, id);
    timeModel = super.timeModel;
}
/**
 * Initialize the data provider.
 */
public void initialize() {
    try {
        topLayerFolder = new File(directory);
        File[] dir = topLayerFolder.listFiles();
        for (File file : dir) {
            loaded.add(file.getName());
        }
        monitorDirectory = new MonitorDirectory();
        monitorDirectory.execute();
    }
    catch (Exception ex) {
        Logger.getLogger(LiveDetectionsProvider.class.getName()).log(Level.SEVERE, "Failed to read detection\n{0}", ex.getMessage());
    }
    super.initialize();
}
/**
 * Un-initialize the data provider.
 */
public void uninitialize() {
    super.uninitialize();
    if (monitorDirectory != null) {
        monitorDirectory.continuing = false;
    }
}
/**
 * The class that is used to load the detection points in a background
 * thread.
 */
protected class MonitorDirectory extends SwingWorker<Void, Void> {
    public boolean continuing = true;
    /**
     * The executor service thread pool.
     */
    private ExecutorService executor = null;
    /**
     * The completion service that reports the completed threads.
     */
    private CompletionService<Object> completionService = null;
    @Override
    protected Void doInBackground() throws Exception {
        int count = 0;
        executor = Executors.newFixedThreadPool(1);
        completionService = new ExecutorCompletionService<>(executor);
        while (continuing && topLayerFolder != null) {
            File[] dir = topLayerFolder.listFiles();
            Thread.sleep(10);
            ArrayList<File> filesToLoad = new ArrayList();
            for (File file : dir) {
                if (!loaded.contains(file.getName())) {
                    long filesize = 0;
                    boolean cont = true;
                    while (cont) {
                        if (file.length() == filesize) {
                            cont = false;
                            Thread.sleep(3);
                            filesToLoad.add(file);
                        }
                        else {
                            filesize = file.length();
                            Thread.sleep(3);
                        }
                    }
                    Thread.sleep(3);
                }
            }
            for (File file : filesToLoad) {
                timeModel.setLoadingData(LiveDetectionsProvider.this.hashCode(), true);
                completionService.submit(Executors.callable(new ReadDetection(file, false)));
                while (completionService.take() == null) {
                    Thread.sleep(2);
                }
                loaded.add(file.getName());
                count++;
                Logger.getLogger(LiveDetectionsProvider.class.getName()).log(Level.SEVERE, "Detection Message Count:" + count);
            }
            detectionsModel.fireStateChanged(DetectionsModel.CHANGE_EVENT_DETECTIONS);
            timeModel.setLoadingData(LiveDetectionsProvider.this.hashCode(), false);
        }
        return null;
    }
}
}

文件在带

completionService.submit(Executors.callable(new ReadDetection(file, false)));

此时的文件还没有完成写入，因此失败。我试过 hibernate 我的线程以减慢它的速度，并且我试过验证文件大小没有改变。我对此的测试用例是我正在解压缩一个包含大量 1,000 KB 文件的 tar 文件。

最佳答案

通常我通过在写入文件时创建一个临时文件来解决这个问题。完成后，我重命名文件，并且只能处理重命名的文件。

关于java - 如何在尝试处理文件之前验证文件是否已完成写入？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/20570753/