Java中监控文件变化的多种方案

package com.test.utils.files;import com.sun.deploy.util.SyncFileAccess;
import org.apache.commons.io.monitor.FileAlterationListenerAdaptor;
import org.apache.commons.io.monitor.FileAlterationMonitor;
import org.apache.commons.io.monitor.FileAlterationObserver;import java.io.File;public class FolderWatcher extends FileAlterationListenerAdaptor {
FileAlterationMonitor monitor; public FolderWatcher(String directory) {
monitor = new FileAlterationMonitor(500);
FileAlterationObserver fileObserver = new FileAlterationObserver(directory);
fileObserver.addListener(this);
monitor.addObserver(fileObserver);
} public void start(boolean isDaemonThread) throws Exception {
if (isDaemonThread) {
monitor.setThreadFactory(r -> {
Thread th = new Thread(r);
th.setDaemon(true);
return th;
});
}
monitor.start();
} @Override
public void onFileChange(File file) {
System.out.println("change" + file);
} @Override
public void onFileCreate(File file) {
while (true) {
try {
SyncFileAccess fileAccess = new SyncFileAccess(file);
SyncFileAccess.FileInputStreamLock lock = fileAccess.openLockFileInputStream(1000, false);lock.getFileInputStream().close();

lock.release();
break;
} catch (Exception e)
{ try { Thread.sleep(100); } catch (InterruptedException ignored) { } } } System.out.println("create:" + file); } }

package com.test.utils.files;import java.io.IOException;
import java.nio.file.*;import static java.nio.file.StandardWatchEventKinds.*;public class FolderWatcher2 {
private WatchService watcher; public FolderWatcher2(String directory) throws IOException {
watcher = FileSystems.getDefault().newWatchService();
Path path = Paths.get(directory);
path.register(watcher, ENTRY_CREATE, ENTRY_MODIFY);
Path path1 = Paths.get(directory, "abc");
path1.register(watcher, ENTRY_CREATE, ENTRY_MODIFY);
}
public void start() throws InterruptedException {
while (true) {
WatchKey key = watcher.take();
for (WatchEvent<?> event : key.pollEvents()) {
WatchEvent.Kind<?> kind = event.kind();
if (kind == OVERFLOW) {//事件可能lost or discarded
continue;
} Path fileName = (Path) event.context();
System.out.printf("Event %s has happened,which fileName is %s%n", kind.name(), fileName);
}
//这行必须有，不然不能连续地监控目录
if (!key.reset()) {
break;
}
}
}}