java WatchService 모니터링 폴더 사용 예

package service;

import config.Config;
import java.io.IOException;
import java.nio.file.*;
import java.util.List;
import java.util.concurrent.TimeUnit;

public class WatchDirService {
  private WatchService watchService;
  private boolean notDone = true;

  public WatchDirService(String dirPath){
    init(dirPath);
  }

  private void init(String dirPath) {
    Path path = Paths.get(dirPath);
    try {
      watchService = FileSystems.getDefault().newWatchService(); // watchService
      path.register(watchService, 
      StandardWatchEventKinds.ENTRY_CREATE,
      StandardWatchEventKinds.ENTRY_MODIFY,
      StandardWatchEventKinds.ENTRY_DELETE); // ,ENTRY_CREATE  ,ENTRY_MODIFY  ,ENTRY_MODIFY  
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

  public void start(){
    System.out.print("watch...");
    while (notDone){
      try {
        WatchKey watchKey = watchService.poll(Config.POLL_TIME_OUT, TimeUnit.SECONDS); // , , WatchKey 
        if(watchKey != null){
          List<WatchEvent<?>> events = watchKey.pollEvents(); // 
          for (WatchEvent event : events){
            WatchEvent.Kind<?> kind = event.kind(); 
            if (kind == StandardWatchEventKinds.OVERFLOW){
              // 
              continue;
            }
            WatchEvent<Path> ev = event;
            Path path = ev.context();
            if(kind == StandardWatchEventKinds.ENTRY_CREATE){
              System.out.println("create " + path.getFileName());
            }else if(kind == StandardWatchEventKinds.ENTRY_MODIFY){
              System.out.println("modify " + path.getFileName());
            }else if(kind == StandardWatchEventKinds.ENTRY_DELETE){
              System.out.println("delete " + path.getFileName());
            }
          }
          if(!watchKey.reset()){ 
            // 
            System.out.println("exit watch server");
            break;
          }
        }
      } catch (InterruptedException e) {
        e.printStackTrace();
        return;
      }
    }
  }
}