JAVA监听文件

import java.io.IOException;
import java.nio.file.FileSystems;
import java.nio.file.Paths;
import java.nio.file.StandardWatchEventKinds;
import java.nio.file.WatchEvent;
import java.nio.file.WatchKey;
import java.nio.file.WatchService;
import java.util.concurrent.TimeUnit;

public class FileLiting {

    public static void main(String[] args) throws IOException, InterruptedException {
        //获取监听路径
        String url = Thread.currentThread().getContextClassLoader().getResource("").getPath();
        url = url.substring(1, url.length()-1);
        WatchService watchService = FileSystems.getDefault().newWatchService();
        //注册文件监听
        Paths.get(url).register(watchService, new WatchEvent.Kind[] {
            StandardWatchEventKinds.ENTRY_DELETE,
            StandardWatchEventKinds.ENTRY_MODIFY
        });
        
        while(true) {
            //三秒拉取
            WatchKey watchKey = watchService.poll(3, TimeUnit.SECONDS);
            if(watchKey==null) {
                System.out.println("没有变化");
                continue;
            }
            for(WatchEvent<?> event:watchKey.pollEvents()) {
                System.out.println("文件名："+event.context().toString());
               if(event.kind()==StandardWatchEventKinds.ENTRY_MODIFY) {
                   System.out.println("文件修改");
               }                
               if(event.kind()==StandardWatchEventKinds.ENTRY_DELETE) {
                   System.out.println("文件删除");
               }
            }
            //监听复位
            watchKey.reset();
        }
    }
    
}