java7文件夹监控

编程技术  /  houtizong 发布于 3年前   115

java7的文件夹监控真是太烂了，折腾了一天，封装的差不多了，结果还是没有jnotify好用！！！ （java7在递归子文件夹目录时貌似原理上有问题，应该真的就是每个文件夹单独注册监听事件吧，所以在拷贝整个文件夹到所监听的目录时，由于还没注册好监听事件，有些文件的创建事件根本无法监听到）！！！

虽然还得加额外的dll，还是用jnotify吧~~，
jnotify网址：http://jnotify.sourceforge.net/

当然，java7可以很好地控制监控的文件夹（不一定整个目录树都得监控不是，自己筛选挺方便）
java7的文件夹监控官方教程：http://docs.oracle.com/javase/tutorial/essential/io/notification.html


以下程序改自官方教程，主要是对事件进行了整合（原本更改文件名称被分为了两个事件delete+create，诸如此类）：

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 static java.nio.file.StandardWatchEventKinds.OVERFLOW;import java.io.IOException;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.Paths;import java.nio.file.SimpleFileVisitor;import java.nio.file.WatchEvent;import java.nio.file.WatchEvent.Kind;import java.nio.file.WatchKey;import java.nio.file.WatchService;import java.nio.file.attribute.BasicFileAttributes;import java.util.ArrayList;import java.util.HashMap;/* * java7文件夹监控程序的封装。 * version: 2012_04_03 */public final class DirWatcher {public static interface WatchEventHandler {void handleEvent(KeyState event);}/** * 记录操作类型 *  */static enum OperationType {/** * @author LC 调整 */Modify {@Overridepublic String toString() {return "Modify";}},/** * @author LC 新建 */Create {@Overridepublic String toString() {return "Create";}},/** * @author LC 删除 */Delete {@Overridepublic String toString() {return "Delete";}},/** * @author LC 空事件 */Null {@Overridepublic String toString() {return "Null";}},/** * @author LC 重命名 */Rename {@Overridepublic String toString() {return "Rename";}},/** * @author LC 没用到 */Move {@Overridepublic String toString() {return "Move";}}}/** * 记录{@link WatchKey}及事件的状态类 */class KeyState {/** * 事件发生的路径或者{@link WatchKey}对应的路径 */public Path path;/** * {@link WatchKey}上一步操作的路径或者重命名事件中的重命名后的名称 */public Path exPath;/** * 事件的类型 */public OperationType opType = OperationType.Null;/** * {@link WatchKey}的等级或者引发事件的{@link WatchKey}的等级 */public int level;/** * 事件发生的事件 */public long opTime = -1;/** * @param path *            事件发生的路径或者{@link WatchKey}对应的路径 * @param level *            {@link WatchKey}的等级或者引发事件的{@link WatchKey}的等级 */public KeyState(Path path, int level) {this.path = path;this.level = level;}/** * @param path *            事件发生的路径或者{@link WatchKey}对应的路径 * @param opType *            操作的类型 * @param level *            {@link WatchKey}的等级或者引发事件的{@link WatchKey}的等级 */public KeyState(Path path, OperationType opType, int level) {this.path = path;this.level = level;this.opType = opType;}/** * @param path *            事件发生的路径或者{@link WatchKey}对应的路径 * @param opType *            操作的类型 * @param level *            {@link WatchKey}的等级或者引发事件的{@link WatchKey}的等级 * @param opTime *            事件发生的时间 */public KeyState(Path path, OperationType opType, int level, long opTime) {super();this.path = path;this.opType = opType;this.level = level;this.opTime = opTime;}@Overridepublic String toString() {StringBuilder sb = new StringBuilder();sb.append("opType=" + opType);sb.append("\topTime=" + opTime);sb.append("\tlevel=" + level);if (path != null)sb.append("\tpath=" + path.normalize());if (exPath != null)sb.append("\texPath=" + exPath.normalize());return sb.toString();}}private Path pathToMonitor;private WatchService ws;/** * 是否监控子目录树 */private boolean watchSubDir = false;/** * 存储键值对应的路径等信息 */private HashMap<WatchKey, KeyState> keyMap = new HashMap<>();/** * 监控的最大层级 */private int maxLevel = 100;/** * 是否输出调试信息 */static boolean debug = true;/** * 处理事件的函数类 */private WatchEventHandler eventHandler;private static final WatchEventHandler nullHandler = new WatchEventHandler() {@Overridepublic void handleEvent(KeyState event) {if (!debug) {System.out.println(event);System.out.println();}}};/** * 演示用 *  * @param pathToMonitor * @param watchSubDir */public DirWatcher(Path pathToMonitor, boolean watchSubDir) {this.pathToMonitor = pathToMonitor;this.watchSubDir = watchSubDir;try {ws = FileSystems.getDefault().newWatchService();if (watchSubDir)registerAll(pathToMonitor, maxLevel);elseregister(pathToMonitor, 0);} catch (IOException e) {e.printStackTrace();}eventHandler = nullHandler;}public DirWatcher(Path pathToMonitor, boolean watchSubDir, int maxLevel,WatchEventHandler eventHandler) {super();this.pathToMonitor = pathToMonitor;this.watchSubDir = watchSubDir;this.maxLevel = maxLevel;this.eventHandler = eventHandler == null ? eventHandler : nullHandler;}@SuppressWarnings("unchecked")static <T> WatchEvent<T> cast(WatchEvent<?> event) {return (WatchEvent<T>) event;}/** * 注册{@link WatchService} *  * @param pathToMonitor *            需要被监控的目录 * @param level *            相对于最上层的要监控的目录的等级，如d:\test为第0级，则d:\test\folder则为1级 * @throws IOException */private void register(Path pathToMonitor, int level) throws IOException {WatchKey key = pathToMonitor.register(ws, ENTRY_CREATE, ENTRY_DELETE,ENTRY_MODIFY);//System.out.println(key + "\t注册key," + dir.toFile().getAbsolutePath());if (debug) {KeyState prev = keyMap.get(key);if (prev == null) {System.out.format("-->\tregister: %s\tregisted level=%d\n",pathToMonitor, level);} else {if (!pathToMonitor.equals(prev.path)) {System.out.format("-->\tupdate: %s -> %s\tregisted level=%d\n", prev,pathToMonitor, level);}}}KeyState prev = keyMap.get(key);if (prev == null)keyMap.put(key, new KeyState(pathToMonitor, level));else {prev.path = pathToMonitor;prev.level = level;}}/** * 监控一个目录及其子目录 *  * @param curPath *            要被监控的目录 * @param maxLevel *            监控的等级数量 * @throws IOException */private void registerAll(final Path curPath, final int maxLevel)throws IOException {registerAll(curPath, 0, maxLevel);}/** * 监控一个目录及其子目录 *  * @param curPath *            要被监控的目录 * @param curLevel *            当前目录相对于最上层的要监控的目录的等级，如d:\test为第0级，则d:\test\folder则为1级 * @param maxLevel *            监控的等级数量，curLevel<maxLevel时，才进行监控 * @throws IOException */private void registerAll(final Path curPath, final int curLevel,final int maxLevel) throws IOException {Files.walkFileTree(curPath, new SimpleFileVisitor<Path>() {int curLv = curLevel;@Overridepublic FileVisitResult preVisitDirectory(Path dir,BasicFileAttributes attrs) throws IOException {if (curLv < maxLevel)register(dir, curLv);++curLv;if (curLv < maxLevel) {return FileVisitResult.CONTINUE;} else {return FileVisitResult.SKIP_SUBTREE;}}@Overridepublic FileVisitResult postVisitDirectory(Path dir, IOException exc)throws IOException {--curLv;return super.postVisitDirectory(dir, exc);}});}/** * 开始监控，事件的处理分为两类 * <p> * 1、对重命名或新增的文件夹的监控，由Oracle的示例完成。 * <p> * 2、文件夹、文件的删除、重命名、新建事件；对于这类事件，Java7处理的不好，会有重复的，对此进行了封装。原理是根据事件发生的顺序及时间间隔来判断 * ，如同一个key的删除接着一个新建实际上为重命名事件 * <p> * 存在的问题：由于Java7系统函数的问题，当把一个含有文件的目录拷贝到监控中的目录时，有些文件无法扫描到！！！！（子目录的监控没有问题） *  */public void startMonitorDir() {new Thread(new Runnable() {@Overridepublic void run() {while (true) {// 等待监控的事件的发生WatchKey key;try {key = ws.take();} catch (InterruptedException e) {e.printStackTrace();return;}//事件的有效性检测KeyState stateOrigin = keyMap.get(key);Path dir = stateOrigin.path;if (dir == null) {System.err.println("WatchKey not recognized!!");}//int keyEventCount = 0;ArrayList<KeyState> eventList = new ArrayList<>();for (WatchEvent<?> event : key.pollEvents()) {Kind<?> kind = event.kind();// 遇到了不关心的事件if (kind == OVERFLOW) {continue;}++keyEventCount;// 获取文件路径WatchEvent<Path> ev = cast(event);Path name = ev.context();//相对路径Path child = dir.resolve(name);//绝对路径//增加到事件队列中KeyState eventState = new KeyState(child,stateOrigin.level);//不使用level字段eventState.opTime = System.currentTimeMillis();if (kind == ENTRY_CREATE) {eventState.opType = OperationType.Create;} else if (kind == ENTRY_DELETE) {eventState.opType = OperationType.Delete;} else if (kind == ENTRY_MODIFY)eventState.opType = OperationType.Modify;eventList.add(eventState);//事件的信息if (debug)System.out.format("%d:%s: %s\n", keyEventCount,event.kind().name(), child);// 如果有新的子目录被创建(或者其他目录更名为该目录)，则加入新的子目录到监控列表中if (watchSubDir && (kind == ENTRY_CREATE)) {try {if (Files.isDirectory(child, NOFOLLOW_LINKS)) {if (debug)System.out.println(key + "\t原始key,"+ keyMap.get(key));registerAll(child, stateOrigin.level + 1,maxLevel);}} catch (IOException e) {//e.printStackTrace();}}}//分析事件队列，获取正确的事件if (eventList.size() == 1) {KeyState state = eventList.get(0);processEvent(key, state);} else if (eventList.size() > 1) {KeyState eventStart;final int size = eventList.size();for (int i = 0; i < size; i++) {eventStart = eventList.get(i);if (i + 1 < size) {KeyState eventEnd = eventList.get(i + 1);//重命名，先删除再创建if (eventStart.opType == OperationType.Delete&& eventEnd.opType == OperationType.Create) {eventStart.opType = OperationType.Rename;eventStart.exPath = eventEnd.path;processEvent(key, eventStart);++i;for (int j = i + 1; j < size; j++) {//过滤掉紧跟的modify事件KeyState tmp = eventList.get(j);if (tmp.path.equals(eventStart.exPath))i++;}} else {processEvent(key, eventStart);for (int j = i + 1; j < size; j++) {//过滤掉紧跟的modify事件KeyState tmp = eventList.get(j);if (tmp.path.equals(eventStart.path))i++;}}} elseprocessEvent(key, eventStart);//if(i+1>=size||evtList.get(i+1).lastOpType!=)}}if (debug)System.out.println();// reset key and remove from set if directory no longer accessibleboolean valid = key.reset();if (!valid) {keyMap.remove(key);// all directories are inaccessibleif (keyMap.isEmpty()) {break;}}}}}).start();}/** * 处理事件，仍需要进行过滤 *  * @param key * @param event */private void processEvent(WatchKey key, KeyState event) {KeyState keyState = keyMap.get(key);if (event.opType != OperationType.Modify|| !event.path.equals(keyState.exPath)|| keyState.opTime - event.opTime > 200) {//同一文件的两个modify时间过短，过滤掉一个（之前也有过滤，但中间可能插入了文件夹的modify事件）；注意keyState中exPath是事件记录，path是监控的文件夹路径if (event.opType != OperationType.Modify|| !Files.isDirectory(event.path, LinkOption.NOFOLLOW_LINKS)) {//过滤文件夹的modify事件，毕竟文件夹modify是因为文件夹下的文件的改变，已经有对应事件了！！！当然，理论上应该再检测一下文件夹是否处于监控列表中，懒得写了，反正都打算用jnotify了！！！if (debug)System.out.println("key=" + key.hashCode() + "\t" + event);eventHandler.handleEvent(event);}}keyState.exPath = event.opType == OperationType.Rename ? event.exPath: event.path;//作为上一步操作的文件进行记录keyState.opTime = event.opTime;}public static void main(String[] args) {DirWatcher watcher = new DirWatcher(Paths.get("D:\\test2"), true);watcher.startMonitorDir();}}