WatchService 可能存在不能再window工作

 1 package chapter1_test;
 2 
 3 import java.io.IOException;
 4 import java.nio.file.FileSystems;
 5 import java.nio.file.Path;
 6 import java.nio.file.StandardWatchEventKinds;
 7 import java.nio.file.WatchEvent;
 8 import java.nio.file.WatchKey;
 9 import java.nio.file.WatchService;
10 
11 public class WatchFileService {
12     /**
13      * @param void
14      * @return void
15      */
16     public static void checkDirChanged(String _dir) {
17         try {
18             //得到默认的WatchService服务
19             WatchService watcher=FileSystems.getDefault().newWatchService();
20             Path dir=FileSystems.getDefault().getPath(_dir);
21             //为Path注册key,可选择的Kind> ENTAY_DELETE，ENTRY_CREATE,ENTRY_MODIFY 等
22             //将Path注册在变化检测名单中
23             WatchKey key=dir.register(watcher, java.nio.file.StandardWatchEventKinds.ENTRY_DELETE);
24             
25             while(true) {
26                 //一旦Watchkey到来，WatchEvent遍历
27                 key=watcher.take();
28 
29                 for(WatchEvent> event:key.pollEvents()) {
30                     //一旦Kind>类型为ENTRY_MODIFY，打印Home dir change
31                     if(event.kind()==StandardWatchEventKinds.ENTRY_DELETE) {
32                         System.out.println("Home dir changed");
33                     }
34                 }
35                 key.reset();
36             }
37         }catch(IOException e) {
38             
39         }catch(InterruptedException e) {
40             System.out.println(e.getMessage());
41         }
42     }
43     public static void main(String[] args) {
44         if(args.length) {
45             System.err.println("命令行参数==0");
46             System.exit(0);
47         }
48         //注意路径的输入，e.g：D:\\testFile,不到再加+"\\"，在jvm中/自动转化成\
49         WatchFileService.checkDirChanged(args[0]);
50     }
51 }