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Javaのディレクトリの変更を監視する

ファイルの変更についてディレクトリを監視したい。そして、Java.nioでWatchServiceを使用しました。ファイル作成イベントを正常にリッスンできます。しかし、ファイル変更イベントをリッスンできません。 official Java tutorial をチェックしましたが、まだ苦労しています。

これがソースコードです。

import static Java.nio.file.LinkOption.NOFOLLOW_LINKS;
import static Java.nio.file.StandardWatchEventKinds.ENTRY_CREATE;
import static Java.nio.file.StandardWatchEventKinds.OVERFLOW;
import static Java.nio.file.StandardWatchEventKinds.ENTRY_DELETE;
import static Java.nio.file.StandardWatchEventKinds.ENTRY_MODIFY;

import Java.io.File;
import Java.io.IOException;
import Java.nio.file.FileSystem;
import Java.nio.file.Files;
import Java.nio.file.Path;
import Java.nio.file.WatchEvent;
import Java.nio.file.WatchEvent.Kind;
import Java.nio.file.WatchKey;
import Java.nio.file.WatchService;

public class MainWatch {

    public static void watchDirectoryPath(Path path) {
        // Sanity check - Check if path is a folder
        try {
            Boolean isFolder = (Boolean) Files.getAttribute(path,
                    "basic:isDirectory", NOFOLLOW_LINKS);
            if (!isFolder) {
                throw new IllegalArgumentException("Path: " + path
                        + " is not a folder");
            }
        } catch (IOException ioe) {
            // Folder does not exists
            ioe.printStackTrace();
        }

        System.out.println("Watching path: " + path);

        // We obtain the file system of the Path
        FileSystem fs = path.getFileSystem();

        // We create the new WatchService using the new try() block
        try (WatchService service = fs.newWatchService()) {

            // We register the path to the service
            // We watch for creation events
            path.register(service, ENTRY_CREATE);
            path.register(service, ENTRY_MODIFY);
            path.register(service, ENTRY_DELETE);

            // Start the infinite polling loop
            WatchKey key = null;
            while (true) {
                key = service.take();

                // Dequeueing events
                Kind<?> kind = null;
                for (WatchEvent<?> watchEvent : key.pollEvents()) {
                    // Get the type of the event
                    kind = watchEvent.kind();
                    if (OVERFLOW == kind) {
                        continue; // loop
                    } else if (ENTRY_CREATE == kind) {
                        // A new Path was created
                        Path newPath = ((WatchEvent<Path>) watchEvent)
                                .context();
                        // Output
                        System.out.println("New path created: " + newPath);
                    } else if (ENTRY_MODIFY == kind) {
                        // modified
                        Path newPath = ((WatchEvent<Path>) watchEvent)
                                .context();
                        // Output
                        System.out.println("New path modified: " + newPath);
                    }
                }

                if (!key.reset()) {
                    break; // loop
                }
            }

        } catch (IOException ioe) {
            ioe.printStackTrace();
        } catch (InterruptedException ie) {
            ie.printStackTrace();
        }

    }

    public static void main(String[] args) throws IOException,
            InterruptedException {
        // Folder we are going to watch
        // Path folder =
        // Paths.get(System.getProperty("C:\\Users\\Isuru\\Downloads"));
        File dir = new File("C:\\Users\\Isuru\\Downloads");
        watchDirectoryPath(dir.toPath());
    }
    }
javafilejava.nio.file
36
Isuru

実際には、イベントを誤ってサブスクライブしています。最後のリスナーのみがENTRY_DELETEイベントタイプに登録されています。

すべての種類のイベントを一度に登録するには、次を使用する必要があります。

 path.register(service, ENTRY_CREATE, ENTRY_MODIFY, ENTRY_DELETE);
30
vvg

警告！恥知らずな自己宣伝！

ディレクトリと任意の数のglobパターンを登録できるJava 1.7のWatchServiceの周りにラッパーを作成しました。クラスはフィルタリングを処理し、関心のあるイベントのみを発行します。

DirectoryWatchService watchService = new SimpleDirectoryWatchService(); // May throw
watchService.register( // May throw
        new DirectoryWatchService.OnFileChangeListener() {
            @Override
            public void onFileCreate(String filePath) {
                // File created
            }

            @Override
            public void onFileModify(String filePath) {
                // File modified
            }

            @Override
            public void onFileDelete(String filePath) {
                // File deleted
            }
        },
        <directory>, // Directory to watch
        <file-glob-pattern-1>, // E.g. "*.log"
        <file-glob-pattern-2>, // E.g. "input-?.txt"
        ... // As many patterns as you like
);

watchService.start();

完全なコードはこの repo にあります。

20
Hindol

このためにいくつかのクラスを作成しました。

public interface FileAvailableListener {
    public void fileAvailable(File file) throws IOException;
}

そして

public class FileChange {

private long lastModified;
private long size;
private long lastCheck;

public FileChange(File file) {
    this.lastModified=file.lastModified();
    this.size=file.length();
    this.lastCheck = System.currentTimeMillis();
}

public long getLastModified() {
    return lastModified;
}
public long getSize() {
    return size;
}
public long getLastCheck() {
    return lastCheck;
}

public boolean isStable(FileChange other,long stableTime) {
    boolean b1 = (getLastModified()==other.getLastModified());
    boolean b2 = (getSize()==other.getSize());
    boolean b3 = ((other.getLastCheck()-getLastCheck())>stableTime);
    return b1 && b2 && b3;
}
}

そして

public class DirectoryWatcher {

private Timer timer;
private List<DirectoryMonitorTask> tasks = new ArrayList<DirectoryMonitorTask>();

public DirectoryWatcher() throws URISyntaxException, IOException, InterruptedException {
    super();
    timer = new Timer(true);        
}
public void addDirectoryMonitoringTask(DirectoryMonitorTask task,long period) {
    tasks.add(task);
    timer.scheduleAtFixedRate(task, 5000, period);      
}
public List<DirectoryMonitorTask> getTasks() {
    return Collections.unmodifiableList(tasks);
}
public Timer getTimer() {
    return timer;
}
}

そして

class DirectoryMonitorTask extends TimerTask {

public final static String DIRECTORY_NAME_ARCHIVE="archive";
public final static String DIRECTORY_NAME_ERROR="error";
public final static String LOCK_FILE_EXTENSION=".lock";
public final static String ERROR_FILE_EXTENSION=".error";   
public final static String FILE_DATE_FORMAT="yyyyMMddHHmmssSSS";

private String name;
private FileAvailableListener listener;
private Path directory;
private File directoryArchive;
private File directoryError;
private long stableTime;
private FileFilter filter;
private WatchService watchService;
private SimpleDateFormat dateFormatter = new SimpleDateFormat(FILE_DATE_FORMAT);
private Hashtable<File,FileChange> fileMonitor = new Hashtable<File,FileChange>();

public DirectoryMonitorTask(String name,FileAvailableListener listener,Path directory,long stableTime,FileFilter filter) throws IOException {
    super();
    this.name=name;
    this.listener=listener;
    this.directory=directory;
    this.stableTime=stableTime;
    if (stableTime<1) {
        stableTime=1000;
    }
    this.filter=filter;
    validateNotNull("Name",name);
    validateNotNull("Listener",listener);
    validateNotNull("Directory",directory);
    validate(directory);
    directoryArchive = new File(directory.toFile(),DIRECTORY_NAME_ARCHIVE);
    directoryError = new File(directory.toFile(),DIRECTORY_NAME_ERROR);
    directoryArchive.mkdir();
    directoryError.mkdir();
    //
    log("Constructed for "+getDirectory().toFile().getAbsolutePath());

    initialize();
    //
    watchService = FileSystems.getDefault().newWatchService();
    directory.register(watchService,StandardWatchEventKinds.ENTRY_CREATE,StandardWatchEventKinds.ENTRY_DELETE,StandardWatchEventKinds.ENTRY_MODIFY);
    log("Started");
}

private void initialize() {
    File[] files = getDirectory().toFile().listFiles();
    for (File file : files) {
        if (isLockFile(file)) {
            file.delete();
        } else if (acceptFile(file)) {
            fileMonitor.put(file,new FileChange(file));
            log("Init file added -"+file.getName());
        }
    }
}
public SimpleDateFormat getDateFormatter() {
    return dateFormatter;
}
public Path getDirectory() {
    return directory;
}
public FileAvailableListener getListener() {
    return listener;
}
public String getName() {
    return name;
}
public WatchService getWatchService() {
    return watchService;
}
public long getStableTime() {
    return stableTime;
}
public File getDirectoryArchive() {
    return directoryArchive;
}
public File getDirectoryError() {
    return directoryError;
}
public FileFilter getFilter() {
    return filter;
}   
public Iterator<File> getMonitoredFiles() {
    return fileMonitor.keySet().iterator();
}

@Override
public void run() {
    WatchKey key;
    try {
        key = getWatchService().take();
        // Poll all the events queued for the key
        for (WatchEvent<?> event : key.pollEvents()) {                                      
            @SuppressWarnings("unchecked")
            Path filePath = ((WatchEvent<Path>) event).context();
            File file = filePath.toFile();
            if ((!isLockFile(file)) && (acceptFile(file))) {
                switch (event.kind().name()) {
                    case "ENTRY_CREATE":
                        //                          
                        fileMonitor.put(file,new FileChange(file));
                        log("File created ["+file.getName()+"]");
                        break;
                        //
                    case "ENTRY_MODIFY":
                        //                          
                        fileMonitor.put(file,new FileChange(file));
                        log("File modified ["+file.getName()+"]");
                        break;  
                        //
                    case "ENTRY_DELETE":
                        //
                        log("File deleted ["+file.getName()+"]");
                        createLockFile(file).delete();
                        fileMonitor.remove(file);                           
                        break;
                        //
                }
            }
        }
        // reset is invoked to put the key back to ready state
        key.reset();
    } catch (InterruptedException e) {              
        e.printStackTrace();
    }

    Iterator<File> it = fileMonitor.keySet().iterator();

    while (it.hasNext()) {
        File file = it.next();  
        FileChange fileChange = fileMonitor.get(file);
        FileChange fileChangeCurrent = new FileChange(file);

        if (fileChange.isStable(fileChangeCurrent, getStableTime())) {
            log("File is stable ["+file.getName()+"]");
            String filename = getDateFormatter().format(new Date())+"_"+file.getName();
            File lockFile = createLockFile(file);
            if (!lockFile.exists()) {
                log("File do not has lock file ["+file.getName()+"]");
                try {
                    Files.createFile(lockFile.toPath());
                    log("Processing file ["+file.getName()+"]");
                    getListener().fileAvailable(file);                      
                    file.renameTo(new File(getDirectoryArchive(),filename));
                    log("Moved to archive file ["+file.getName()+"]");
                } catch (IOException e) {                       
                    file.renameTo(new File(getDirectoryError(),filename));
                    createErrorFile(file,e);
                    log("Moved to error file ["+file.getName()+"]");
                } finally {
                    lockFile.delete();

                }
            } else {                    
                log("File do has lock file ["+file.getName()+"]");
                fileMonitor.remove(file);
            }               
        } else {                
            log("File is unstable ["+file.getName()+"]");
            fileMonitor.put(file,fileChangeCurrent);
        }
    }       
}

public boolean acceptFile(File file) {
    if (getFilter()!=null) {
        return getFilter().accept(file);
    } else {
        return true;
    }       
}

public boolean isLockFile(File file) {
    int pos = file.getName().lastIndexOf('.');
    String extension="";
    if (pos!=-1) {
        extension = file.getName().substring(pos).trim().toLowerCase();
    }   
    return(extension.equalsIgnoreCase(LOCK_FILE_EXTENSION));
}

private File createLockFile(File file) {
    return new File(file.getParentFile(),file.getName()+LOCK_FILE_EXTENSION);
}

private void createErrorFile(File file,IOException exception) {
    File errorFile = new File(file.getParentFile(),file.getName()+ERROR_FILE_EXTENSION);

    StringWriter sw = null;
    PrintWriter pw = null;
    FileWriter fileWriter = null;
    try {
        //          
        fileWriter = new FileWriter(errorFile);
        if (exception!=null) {
            sw = new StringWriter();
            pw = new PrintWriter(sw);
            exception.printStackTrace(pw);      
            fileWriter.write(sw.toString());
        } else {
            fileWriter.write("Exception is null.");
        }
        //      
        fileWriter.flush();
        //
    } catch (IOException e) {
    } finally {
        if (sw!=null) {
            try {
                sw.close();
            } catch (IOException e1) {              
            }
        }
        if (pw!=null) {
            pw.close();
        }
        if (fileWriter!=null) {
            try {
                fileWriter.close();
            } catch (IOException e) {                   
            }
        }
    }
}

private void validateNotNull(String name,Object obj) {
    if (obj==null) {
        throw new NullPointerException(name+" is null.");
    }           
}       
private void validate(Path directory) throws IOException {          
    File file = directory.toFile();
    if (!file.exists()) {
        throw new IOException("Directory ["+file.getAbsolutePath()+"] do not exists.");
    } else if (!file.isDirectory()) {
        throw new IOException("Directory ["+file.getAbsolutePath()+"] is not a directory.");
    } else if (!file.canRead()) {               
        throw new IOException("Can not read from directory ["+file.getAbsolutePath()+"].");
    } else if (!file.canWrite()) {
        throw new IOException("Can not write to directory ["+file.getAbsolutePath()+"] .");
    }       
}

private void log(String msg) {
    //TODO
    System.out.println("Task ["+getName()+"] "+msg);
}
}
2
FrederikH
package p1;

import Java.io.File;
import Java.io.IOException;
import Java.nio.file.Files;
import Java.nio.file.Path;
import Java.nio.file.Paths;
import static Java.nio.file.LinkOption.NOFOLLOW_LINKS;
import Java.nio.file.StandardWatchEventKinds;
import Java.nio.file.WatchEvent;
import Java.nio.file.WatchKey;
import Java.nio.file.WatchService;
import Java.util.List;

public class WatchForFile {

    public void WatchMyFolder(String path )
    {
        File dir = new File(path);
        Path myDir= dir.toPath();
          try 
          {
              Boolean isFolder = (Boolean) Files.getAttribute(myDir,"basic:isDirectory", NOFOLLOW_LINKS);
              if (!isFolder)
              {
                  throw new IllegalArgumentException("Path: " + myDir + " is not a folder");
              }
          }
          catch (IOException ioe)
          {
              ioe.printStackTrace();
          }

          System.out.println("Watching path: " + myDir);

        try {
           WatchService watcher = myDir.getFileSystem().newWatchService();
           myDir.register(watcher, StandardWatchEventKinds.ENTRY_CREATE,StandardWatchEventKinds.ENTRY_DELETE, StandardWatchEventKinds.ENTRY_MODIFY);

           WatchKey watckKey = watcher.take();

           List<WatchEvent<?>> events = watckKey.pollEvents();

           for (WatchEvent event : events) {
                if (event.kind() == StandardWatchEventKinds.ENTRY_CREATE) {
                    System.out.println("Created: " + event.kind().toString());

                }
                if (event.kind() == StandardWatchEventKinds.ENTRY_DELETE) {
                    System.out.println("Delete: " + event.context().toString());
                }
                if (event.kind() == StandardWatchEventKinds.ENTRY_MODIFY) {
                    System.out.println("Modify: " + event.context().toString());
                }
            }

        }
        catch (Exception e) 
        {
            System.out.println("Error: " + e.toString());
        }
    }
}
1
P RAJESH

このコードを確認...

https://github.com/omkar9999/FileWatcherHandler

このプロジェクトでは、作成、変更、削除などのさまざまなファイルイベントのファイルを監視し、これらのイベントを一般的な方法で処理できます。

使用方法
ファイルイベントを監視するディレクトリを表すPathオブジェクトを作成します。

Path path = Paths.get("/home/omkar/test");

FileHandlerインターフェイスを実装して、登録されたファイルイベントによって検出されたアクションを実行します。

public class FileHandlerTest implements FileHandler {

    private static final Logger LOGGER = Logger.getLogger(FileHandlerTest.class.getName());

    /*
     * This implemented method will delete the file
     * 
     * @see com.io.util.FileHandler#handle(Java.io.File,
     * Java.nio.file.WatchEvent.Kind)
     */
    public void handle(File file, Kind<?> fileEvent) {
        LOGGER.log(Level.INFO,"Handler is triggered for file {0}",file.getPath());
        if(fileEvent == StandardWatchEventKinds.ENTRY_CREATE) {
            try {
                boolean deleted = Files.deleteIfExists(Paths.get(file.getPath()));
                assertTrue(deleted);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

}

実装されたFileHandlerのインスタンスを作成します

FileHandlerTest fileHandlerTest = new FileHandlerTest();

パス、実装されたFileHandlerのインスタンス、および監視するファイルイベントの種類をコンマで区切って渡すことにより、FileWatcherのインスタンスを作成します。

FileWatcher fileWatcher = new FileWatcher(path, fileHandlerTest, StandardWatchEventKinds.ENTRY_CREATE);

次に、新しいスレッドを作成して開始します。

Thread watcherThread = new Thread(fileWatcher);
watcherThread.start();

このスレッドは、登録済みファイルイベントのポーリングを開始し、登録済みイベントのいずれかが検出されると、カスタムハンドルメソッドを呼び出します。

0
omkar marathe

パブリッククラスFileWatcherはRunnable {

private static final Logger LOGGER =Logger.getLogger(FileWatcher.class.getName());

private WatchService watcher;
private FileHandler fileHandler;
private List<Kind<?>> watchedEvents;
private Path directoryWatched;

/**
 * @param directory
 * @Path directory to watch files into
 * @param fileHandler
 * @FileHandler implemented instance to handle the file event
 * @param watchRecursive
 *            if directory is to be watched recursively
 * @param watchedEvents
 *            Set of file events watched
 * 
 * @throws IOException
 */
public FileWatcher(Path directory, FileHandler fileHandler, boolean watchRecursive,
        WatchEvent.Kind<?>... watchedEvents) throws IOException {
    super();
    this.watcher = FileSystems.getDefault().newWatchService();
    this.fileHandler = fileHandler;
    this.directoryWatched = directory;
    this.watchedEvents = Arrays.asList(watchedEvents);
    if (watchRecursive) {
        // register all subfolders
        Files.walkFileTree(directory, new SimpleFileVisitor<Path>() {
            @Override
            public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException {
                LOGGER.log(Level.INFO, "Registering {0} ", dir);
                dir.register(watcher, StandardWatchEventKinds.ENTRY_CREATE, StandardWatchEventKinds.ENTRY_DELETE,
                        StandardWatchEventKinds.ENTRY_MODIFY);
                return FileVisitResult.CONTINUE;
            }
        });
    } else {
        directory.register(watcher, watchedEvents);
    }
}

@SuppressWarnings({ "unchecked" })
public void run() {
    LOGGER.log(Level.INFO, "Starting FileWatcher for {0}", directoryWatched.toAbsolutePath());
    WatchKey key = null;
    while (true) {
        try {
            key = watcher.take();
            if (key != null) {
                for (WatchEvent<?> event : key.pollEvents()) {
                    WatchEvent.Kind<?> kind = event.kind();

                    WatchEvent<Path> ev = (WatchEvent<Path>) event;
                    //directory in which file event is detected
                    Path directory = (Path) key.watchable(); 
                    Path fileName = ev.context();
                    if (watchedEvents.contains(kind)) {
                        LOGGER.log(Level.INFO, "Invoking handle on {0}", fileName.toAbsolutePath());
                        fileHandler.handle(directory.resolve(fileName).toFile(), kind);
                    }
                }
                key.reset();
            }
        } catch (InterruptedException ex) {
            LOGGER.log(Level.SEVERE, "Polling Thread was interrupted ", ex);
            Thread.currentThread().interrupt();
        }
    }
}

}

0
user6440666