FileMonitor 基于jdk7文件监控WatchService

package com.tommy.file.monitor; import static java.nio.file.LinkOption.NOFOLLOW_LINKS; import static java.nio.file.StandardWatchEventKinds.ENTRY_CREATE; 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.ClosedWatchServiceException; import java.nio.file.FileSystems; import java.nio.file.FileVisitResult; import java.nio.file.Files; import java.nio.file.LinkOption; import java.nio.file.Path; import java.nio.file.SimpleFileVisitor; import java.nio.file.StandardWatchEventKinds; import java.nio.file.WatchEvent; import java.nio.file.WatchKey; import java.nio.file.WatchService; import java.nio.file.attribute.BasicFileAttributes; import java.util.Iterator; import java.util.List; import java.util.Objects; import java.util.concurrent.CopyOnWriteArrayList; import java.util.concurrent.TimeUnit; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import com.tommy.file.monitor.exception.MonitorException; import com.tommy.file.monitor.listener.Listener; /** * Usage FileMonitor monitor = FileMonitors.newFileMonitor(); * monitor.addWatch(new File("...")); monitor.register(listener); * monitor.start(); * * ... monitor.stop(); * * 注意： monitor.start()， 该方法并不会产生新线程，如果有需要，请在线程里调用monitor.start() * * @author Administrator * */ public class FileMonitor { private static final Log LOG = LogFactory.getLog(FileMonitor.class); private WatchService watchService; private final List<Listener> listeners = new CopyOnWriteArrayList<>(); private static final int EVENT_RENAME_FIEL_MODIFIER = 1; private static final int EVENT_RENAME_DIRECTORY_MODIFIER = 2; private static final int EVENT_NOT_RENAME_MODIFIER = -1; private static final long WAIT_EVNET_POLL_PERIOD = 200L; public FileMonitor() { tryInitWatchService(); } private final void tryInitWatchService() { try { this.watchService = FileSystems.getDefault().newWatchService(); } catch (IOException e) { throw new MonitorException(e); } catch (UnsupportedOperationException ue) { throw new MonitorException.UnsupportMonitorException(); } } public boolean register(Listener listener) { Objects.requireNonNull(listener); return listeners.add(listener); } public boolean unregister(Listener listener) { Objects.requireNonNull(listener); return listeners.remove(listener); } public void addWatch(File dir) { addWatch(dir, false); } public void addWatch(File dir, boolean recurse) { validateDir(dir); notifyListEvent(dir); Path watchPath = dir.toPath(); if (!recurse) { register(watchPath, true); } else { registerAll(watchPath, true); } } private void notifyListEvent(File dir) { for (Listener listener : listeners) { listener.list(dir); } } private void notifySimpleEvent(WatchEvent<Path> watchEvent, WatchKey key) { try { Path dirPath = (Path) key.watchable(); File contextFile = dirPath.resolve(watchEvent.context()).toFile(); if (watchEvent.kind() == ENTRY_CREATE) { for (Listener listener : listeners) { listener.fileCreated(dirPath.toFile(), contextFile); } } else if (watchEvent.kind() == ENTRY_DELETE) { for (Listener listener : listeners) { listener.fileDelete(dirPath.toFile(), contextFile); } } else if (watchEvent.kind() == ENTRY_MODIFY) { for (Listener listener : listeners) { listener.fileModified(dirPath.toFile(), contextFile); } } else { LOG.error("Unknown watchEvent.Kind : " + watchEvent.kind().name()); } } catch (Exception e) { LOG.error(e.toString(), e); } } private void notifyRenamedEvent(File dir, File oldFile, File newFile) { try { for (Listener listener : listeners) { listener.fileRenamed(dir, oldFile, newFile); } } catch (Exception e) { // if error occurs , log it and go on monitor LOG.error(e.toString(), e); } } private boolean running = false; /** * 开启监控，该方法不会产生新线程 */ public void start() { if (isRunning()) { throw new MonitorException("File Monitor: " + this + " has Running."); } synchronized (this) { running = true; } processEvents(); } public synchronized void stop() { if (!isRunning()) { throw new MonitorException("File Monitor: " + this + " already stoped."); } synchronized (this) { running = false; } try { watchService.close(); } catch (IOException e) { throw new MonitorException("Stop watchService encounter error. ", e); } } public synchronized boolean isRunning() { return running; } private void processEvents() { for (;;) { if (!isRunning()) { LOG.info("File Monitor stoped."); break; } WatchKey key; try { key = watchService.take(); } catch (InterruptedException e) { if (isRunning()) { throw new MonitorException( "FileMonitor interrupted unexpectedly.", e); } else { LOG.info("FileMonitor interrupted."); return; } } catch (ClosedWatchServiceException e) { if (isRunning()) { throw new MonitorException( "FileMonitor's watchService closed unexpectedly.", e); } else { LOG.info("FileMonitor closed."); return; } } // wait events produce fully try { TimeUnit.MILLISECONDS.sleep(WAIT_EVNET_POLL_PERIOD); } catch (InterruptedException ignore) { // ignore this exception } List<WatchEvent<?>> events = key.pollEvents(); if (events == null || events.isEmpty()) { continue; } Path watchPath = (Path) key.watchable(); // remove overflow event filterEvents(events); /** * analyse event */ int eventModifier = getEventModifier(events, key); if (eventModifier == EVENT_RENAME_FIEL_MODIFIER || eventModifier == EVENT_RENAME_DIRECTORY_MODIFIER) { File oldFile = watchPath .resolve((Path) events.get(0).context()).toFile(); File newFile = watchPath .resolve((Path) events.get(1).context()).toFile(); File dir = watchPath.toFile(); if (events.get(1).kind() == ENTRY_CREATE) { Path child = watchPath.resolve((Path) events.get(1) .context()); if (Files.isDirectory(child, NOFOLLOW_LINKS)) { registerAll(child, false); } } notifyRenamedEvent(dir, oldFile, newFile); } else { for (WatchEvent<?> watchEvent : events) { if (watchEvent.kind() == StandardWatchEventKinds.OVERFLOW) { continue; } WatchEvent<Path> ev = cast(watchEvent); Path name = ev.context(); if (ev.kind() == ENTRY_CREATE) { Path child = watchPath.resolve(name); // recurse all or just it self? if (Files.isDirectory(child, NOFOLLOW_LINKS)) { registerAll(child, false); } } notifySimpleEvent(ev, key); } } boolean valid = key.reset(); if (!valid) { LOG.info("Path '" + key.watchable() + "' not monitor."); } } } private void filterEvents(List<WatchEvent<?>> events) { Iterator<WatchEvent<?>> it = events.iterator(); while (it.hasNext()) { if (it.next().kind() == StandardWatchEventKinds.OVERFLOW) { it.remove(); } } } private int getEventModifier(List<WatchEvent<?>> events, WatchKey key) { int len = events.size(); if (len != 2 && len != 3) { return EVENT_NOT_RENAME_MODIFIER; } WatchEvent<Path> deleteEvent = cast(events.get(0)); WatchEvent<Path> createEvent = cast(events.get(1)); WatchEvent<Path> modifyEvent = null; if (len == 3) { modifyEvent = cast(events.get(2)); } // cr