java7 NIO2(6) watching service API

java7 NIO2新增了文件系统的相关事件处理API，为目录，文件新增修改删除等事件添加事件处理。

package com.mime;import java.io.IOException;import java.nio.file.FileSystems;import java.nio.file.Path;import java.nio.file.Paths;import java.nio.file.StandardWatchEventKinds;import java.nio.file.WatchEvent;import java.nio.file.WatchEvent.Kind;import java.nio.file.WatchKey;import java.nio.file.WatchService;public class NIO2WatchService {//WatchService 是线程安全的，跟踪文件事件的服务，一般是用独立线程启动跟踪public void watchRNDir(Path path) throws IOException, InterruptedException {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);// start an infinite loopwhile (true) {// retrieve and remove the next watch keyfinal WatchKey key = watchService.take();// get list of pending events for the watch keyfor (WatchEvent<?> watchEvent : key.pollEvents()) {// get the kind of event (create, modify, delete)final Kind<?> kind = watchEvent.kind();// handle OVERFLOW eventif (kind == StandardWatchEventKinds.OVERFLOW) {continue;}//创建事件if(kind == StandardWatchEventKinds.ENTRY_CREATE){}//修改事件if(kind == StandardWatchEventKinds.ENTRY_MODIFY){}//删除事件if(kind == StandardWatchEventKinds.ENTRY_DELETE){}// get the filename for the eventfinal WatchEvent<Path> watchEventPath = (WatchEvent<Path>) watchEvent;final Path filename = watchEventPath.context();// print it outSystem.out.println(kind + " -> " + filename);}// reset the keyfboolean valid = key.reset();// exit loop if the key is not valid (if the directory was// deleted, forif (!valid) {break;}}}}/** * @param args */public static void main(String[] args) {final Path path = Paths.get("/tmp");NIO2WatchService watch = new NIO2WatchService();try {watch.watchRNDir(path);} catch (IOException | InterruptedException ex) {System.err.println(ex);}}}