jdk 1.7 监听文件目录

 package com;


import java.io.IOException;
import java.nio.file.FileSystem;
import java.nio.file.FileSystems;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.WatchEvent;
import java.nio.file.WatchKey;
import java.nio.file.WatchService;
import java.util.List;




import static java.nio.file.StandardWatchEventKinds.*;
public class Test {
    WatchService watch;
    
    public Test(Path path) throws IOException {
    watch = FileSystems.getDefault().newWatchService();
    path.register(watch,ENTRY_CREATE,ENTRY_DELETE,ENTRY_MODIFY);
    }

    public void handleEvents() throws InterruptedException{
        while(true){
            WatchKey key = watch.take();
            for(WatchEvent event : key.pollEvents()){
                WatchEvent.Kind kind = event.kind();


                if(kind == OVERFLOW){//事件可能lost or discarded
                    continue;
                }


                WatchEvent e = (WatchEvent)event;
                Path fileName = (Path) e.context();


                System.out.printf("Event %s has happened,which fileName is %s%n"
                        ,kind.name(),fileName);

            }

           //如果事件invail

            if(!key.reset()){
                break;
            }
        }
    }
    
    public static void main(String[] args) {
try {
new Test(Paths.get("F://")).handleEvents();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}