Java实现实时监控目录下文件变化的方法

<!-- https://mvnrepository.com/artifact/commons-io/commons-io --><dependency>  <groupId>commons-io</groupId>  <artifactId>commons-io</artifactId>  <version>2.6</version></dependency>

import java.io.File;import org.apache.commons.io.monitor.FileAlterationListenerAdaptor;import org.apache.commons.io.monitor.FileAlterationObserver;import org.apache.log4j.Logger;/** * 文件变化监听器 * 在Apache的Commons-IO中有关于文件的监控功能的代码. 文件监控的原理如下： * 由文件监控类FileAlterationMonitor中的线程不停的扫描文件观察器FileAlterationObserver， * 如果有文件的变化，则根据相关的文件比较器，判断文件时新增，还是删除，还是更改。（默认为1000毫秒执行一次扫描） */public class FileListener extends FileAlterationListenerAdaptor {  private Logger log = Logger.getLogger(FileListener.class);  /**   * 文件创建执行   */  public void onFileCreate(File file) {    log.info("[新建]:" + file.getAbsolutePath());  }  /**   * 文件创建修改   */  public void onFileChange(File file) {    log.info("[修改]:" + file.getAbsolutePath());  }  /**   * 文件删除   */  public void onFileDelete(File file) {    log.info("[删除]:" + file.getAbsolutePath());  }  /**   * 目录创建   */  public void onDirectoryCreate(File directory) {    log.info("[新建]:" + directory.getAbsolutePath());  }  /**   * 目录修改   */  public void onDirectoryChange(File directory) {    log.info("[修改]:" + directory.getAbsolutePath());  }  /**   * 目录删除   */  public void onDirectoryDelete(File directory) {    log.info("[删除]:" + directory.getAbsolutePath());  }  public void onStart(FileAlterationObserver observer) {    // TODO Auto-generated method stub    super.onStart(observer);  }  public void onStop(FileAlterationObserver observer) {    // TODO Auto-generated method stub    super.onStop(observer);  }}

public static void main(String[] args) throws Exception{    // 监控目录    String rootDir = "D://apache-tomcat-7.0.78";    // 轮询间隔 5 秒    long interval = TimeUnit.SECONDS.toMillis(1);    // 创建过滤器    IOFileFilter directories = FileFilterUtils.and(        FileFilterUtils.directoryFileFilter(),        HiddenFileFilter.VISIBLE);    IOFileFilter files    = FileFilterUtils.and(        FileFilterUtils.fileFileFilter(),        FileFilterUtils.suffixFileFilter(".txt"));    IOFileFilter filter = FileFilterUtils.or(directories, files);    // 使用过滤器    FileAlterationObserver observer = new FileAlterationObserver(new File(rootDir), filter);    //不使用过滤器    //FileAlterationObserver observer = new FileAlterationObserver(new File(rootDir));    observer.addListener(new FileListener());    //创建文件变化监听器    FileAlterationMonitor monitor = new FileAlterationMonitor(interval, observer);    // 开始监控    monitor.start();  }

public static void main(String[] a) {    final Path path = Paths.get("D://apache-tomcat-7.0.78");    try (WatchService watchService = FileSystems.getDefault().newWatchService()) {      //给path路径加上文件观察服务      path.register(watchService, StandardWatchEventKinds.ENTRY_CREATE,          StandardWatchEventKinds.ENTRY_MODIFY,          StandardWatchEventKinds.ENTRY_DELETE);      while (true) {        final WatchKey key = watchService.take();        for (WatchEvent<?> watchEvent : key.pollEvents()) {          final WatchEvent.Kind<?> kind = watchEvent.kind();          if (kind == StandardWatchEventKinds.OVERFLOW) {            continue;          }          //创建事件          if (kind == StandardWatchEventKinds.ENTRY_CREATE) {            System.out.println("[新建]");          }          //修改事件          if (kind == StandardWatchEventKinds.ENTRY_MODIFY) {            System.out.println("修改]");          }          //删除事件          if (kind == StandardWatchEventKinds.ENTRY_DELETE) {            System.out.println("[删除]");          }          // get the filename for the event          final WatchEvent<Path> watchEventPath = (WatchEvent<Path>) watchEvent;          final Path filename = watchEventPath.context();          // print it out          System.out.println(kind + " -> " + filename);        }        boolean valid = key.reset();        if (!valid) {          break;        }      }    } catch (IOException | InterruptedException ex) {      System.err.println(ex);    }  }