我一直在尝试通过UNC监视文件夹。主文件夹中有很多文件夹。当我运行监视服务时，它正在向监视服务注册所有文件夹。注册所有这些文件夹后，监视服务接收具有无效键的事件 i-e key.isValid() 返回 false。此时，特定文件夹已从监视中排除。我已经重置了密钥，但它也给了我错误。简而言之，我无法监视那些从密钥中排除的文件夹。我什至尝试重新注册文件夹，但这再次生成无效密钥并且无法监视。我已经在同一台机器上的普通文件夹中尝试过这个。他们工作正常。如果我错过了什么，请帮助我。如果我将文件夹限制在 50-60 左右，手表服务不会收到任何无效的密钥事件，并且一切正常。
这是将创建文件夹数量的代码。
import java.io.File;
public class CreateDir {
public static void main(String args[]){
for(int j=0; j<1000; j++){
String folderName = "Folder"+j;
new File("\\Server2\Shared Folder\test\" + folderName + "\" + folderName + "_Folder1" + "\" + folderName + "_Folder2" + "\"
+ folderName + "_Folder3" + "\" + folderName + "_Folder4" + "\" + folderName + "_Folder5"+"\"
+ folderName + "_Folder6" + "\" + folderName + "_Folder7" + "\" + folderName + "_Folder8" + "\"
+ folderName + "_Folder9" + "\" + folderName + "_Folder10").mkdirs();
}
}
}
这是实际监视这些 UNC 路径并提供有关事件的信息的类。
import java.nio.file.*;
import static java.nio.file.StandardWatchEventKinds.*;
import static java.nio.file.LinkOption.*;
import java.nio.file.attribute.*;
import java.io.*;
import java.util.*;
public class WatchDir {
private final WatchService watcher;
private final Map<WatchKey,Path> keys;
private final boolean recursive;
private boolean trace = false;
private int total = 0;
@SuppressWarnings("unchecked")
static <T> WatchEvent<T> cast(WatchEvent<?> event) {
return (WatchEvent<T>)event;
}
/**
* Register the given directory with the WatchService
*/
private void register(Path dir, PrintWriter writer) throws IOException {
WatchKey key = dir.register(watcher, ENTRY_CREATE, ENTRY_DELETE, ENTRY_MODIFY);
if (trace) {
Path prev = keys.get(key);
if (prev == null) {
writer.println("register:"+dir);
} else {
if (!dir.equals(prev)) {
writer.println("update.........");
}
}
}
keys.put(key, dir);
}
/**
* Register the given directory, and all its sub-directories, with the
* WatchService.
*/
private void registerAll(final Path start, PrintWriter writer){
// register directory and sub-directories
try{
Files.walkFileTree(start, new SimpleFileVisitor<Path>() {
@Override
public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs)
{
writer.println(++total+"Registering Path...."+dir.toUri());
try{
register(dir,writer);
}catch(IOException ex){
writer.println("Error occurred for Path..."+dir.getFileName());
}catch(Exception ex){
System.out.println("error");
}
return FileVisitResult.CONTINUE;
}
});
}catch(Exception ex){
writer.println("Not Registered ....."+ex.getMessage());
}
}
/**
* Creates a WatchService and registers the given directory
*/
WatchDir(Path dir, boolean recursive, PrintWriter writer) throws IOException {
this.watcher = FileSystems.getDefault().newWatchService();
this.keys = new HashMap<WatchKey,Path>();
this.recursive = recursive;
if (recursive) {
System.out.println("Starting Registering Path");
writer.println("Scanning %s ...n"+ dir);
registerAll(dir, writer);
writer.println("Done.");
System.out.println("Done");
writer.println("Total Folders in Watch "+ total);
System.out.println("Total Folders in Watch "+ total);
} else {
register(dir,writer);
}
// enable trace after initial registration
this.trace = true;
}
/**
* Process all events for keys queued to the watcher
* @throws UnsupportedEncodingException
* @throws FileNotFoundException
*/
void processEvents() throws FileNotFoundException, UnsupportedEncodingException {
PrintWriter writer1 = new PrintWriter("C:\test\key.txt");
for (;;) {
// wait for key to be signalled
WatchKey key;
try {
key = watcher.take();
writer1.println("Folder is "+key.watchable()+" And Key is "+ key.isValid());
System.out.println("Folder is "+key.watchable()+" And Key is "+ key.isValid());
} catch (InterruptedException x) {
writer1.println("Interupped Exception.........");
return;
}
Path dir = keys.get(key);
if (dir == null) {
writer1.println("WatchKey not recognized!!");
continue;
}
for (WatchEvent<?> event: key.pollEvents()) {
WatchEvent.Kind kind = event.kind();
// TBD - provide example of how OVERFLOW event is handled
if (kind == OVERFLOW) {
writer1.println("Overflow event is caught.");
continue;
}
// Context for directory entry event is the file name of entry
WatchEvent<Path> ev = cast(event);
Path name = ev.context();
Path child = dir.resolve(name);
// print out event
System.out.format("%s: %sn", event.kind().name(), child);
writer1.println("Event Kind is "+event.kind().name() +" And Name is "+child);
// if directory is created, and watching recursively, then
// register it and its sub-directories
if (recursive && (kind == ENTRY_CREATE)) {
try {
if (Files.isDirectory(child, NOFOLLOW_LINKS)) {
registerAll(child, writer1);
}
} catch (Exception x) {
// ignore to keep sample readbale
}
}
}
// reset key and remove from set if directory no longer accessible
boolean valid = key.reset();
if (!valid) {
keys.remove(key);
// all directories are inaccessible
if (keys.isEmpty()) {
break;
}
}
}
}
static void usage() {
System.err.println("usage: java WatchDir [-r] dir");
System.exit(-1);
}
public static void main(String[] args) throws IOException {
// register directory and process its events
PrintWriter writer = new PrintWriter("C:\test\watch.txt");
Path dir = Paths.get("\\Server1\Shared Folder\test");
new WatchDir(dir, true,writer).processEvents();
}
}
我已经在JDK8和JDK 11上尝试过这个，两者都给出了相同的问题。
您应该尝试在注册中使用ExtendedWatchEventModifier.FILE_TREE，而不是单独注册每个子目录(仅限 Windows)。
我不知道这是否解决了无效键的问题，但它肯定会使您的代码更简单。