web项目启动时配置监听本地目录文件添加, 删除, 修改, 等操作

 1 package com.mtl.fill.listener;
 2 
 3 
 4 import com.mtl.fill.utils.ListenFile;
 5 
 6 import javax.servlet.ServletContextEvent;
 7 import javax.servlet.ServletContextListener;
 8 
 9 public class MyListener implements ServletContextListener {
10     @Override
11     public void contextInitialized(ServletContextEvent servletContextEvent) {
12         new Thread(new ListenFile()).start();
13     }
14 
15     @Override
16     public void contextDestroyed(ServletContextEvent servletContextEvent) {
17 
18     }
19 
20 }

 1 package com.mtl.fill.utils;
 2 
 3 import java.io.*;
 4 import java.nio.file.*;
 5 
 6 public class ListenFile implements Runnable {
 7 
 8     @Override
 9     public void run() {
10         //获取文件系统的WatchService对象
11         WatchService watchService = null;
12         try {
13             watchService = FileSystems.getDefault().newWatchService();
14             //为C：盘根路径注册监听
15             Paths.get("D://scai_client").register(watchService
16                     //监听创建操作
17                     , StandardWatchEventKinds.ENTRY_CREATE
18                     //监听删除操作
19                     ,StandardWatchEventKinds.ENTRY_DELETE
20                     //监听修改操作
21                     ,StandardWatchEventKinds.ENTRY_MODIFY);
22             //死循环一直监听
23             while(true) {
24                 //一直等待，直到获取下一个文件变化事件
25                 WatchKey key = watchService.take();
26                 //遍历监控获得的事件列表
27                 for (WatchEvent<?> event : key.pollEvents()) {
28                     //event.context()返回触发事件的文件或目录
29                     System.out.println(event.context() + "发生了" + event.kind()+ "事件");
30                 }
31                 //重新设置WatchKey
32                 boolean valid = key.reset();
33                 //如果设置失败则退出监听
34                 if (!valid) {
35                     break;
36                 }
37             }
38         } catch (IOException e) {
39             e.printStackTrace();
40         } catch (InterruptedException e) {
41             e.printStackTrace();
42         }
43     }
44 }