WatchDirService 实时监控

 import config.Config;

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

 /**
  * Created by jason on 2017/2/14.
  */
 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();
             path.register(watchService, StandardWatchEventKinds.ENTRY_CREATE,StandardWatchEventKinds.ENTRY_MODIFY,StandardWatchEventKinds.ENTRY_DELETE);
         } 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);
                 System.out.print("change");
                 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;
             }
         }
     }
 }