java 7 監控文件狀態(修改，刪除，增長)

 package com.filewatch; 

 import static java.nio.file.StandardWatchEventKinds.ENTRY_CREATE; import static java.nio.file.StandardWatchEventKinds.ENTRY_DELETE; import static java.nio.file.StandardWatchEventKinds.ENTRY_MODIFY; import static java.nio.file.StandardWatchEventKinds.OVERFLOW; 

 import java.io.File; import java.io.IOException; 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.text.SimpleDateFormat; import java.util.Date; import java.util.Map; import java.util.concurrent.ConcurrentHashMap;   public class FileWatch {      Map<WatchKey,Path> keys = new ConcurrentHashMap<WatchKey,Path>();      private static WatchService watcher = null;            static {          try {              watcher = FileSystems.getDefault().newWatchService();  //構建文件監控服務         } catch (IOException e) {              e.printStackTrace();          }         }               private void register(Path dir) throws IOException { // IOException ,InterruptedException{          WatchKey key = dir.register(watcher, ENTRY_CREATE,ENTRY_DELETE,ENTRY_MODIFY);   //給文件註冊監聽事件             Path existing = keys.get(key);            if (existing == null) {                System.out.format("register: %s\n", dir);            } else if (!dir.equals(existing)){                 System.out.format("update: %s -> %s\n",existing, dir);            }                       keys.put(key, dir);       }            @SuppressWarnings("unchecked")       static <T> WatchEvent<Path> cast(WatchEvent<?> event) {           return (WatchEvent<Path>)event;       }       private void registPath(File files) throws IOException{       for (File file:files.listFiles()) {     if(file.isDirectory()){       register(Paths.get(file.getPath()));       registPath(file);     }    }     }         private void fileWatch(Path dir) throws IOException,InterruptedException{               register(dir);//先註冊主文件夾         registPath(dir.toFile());//再經過遞歸方式將子文件夾也註冊進去         while(true){          // 等待監視事件發生           WatchKey key = watcher.take();                   // System.out.println(key.getClass().getName());           Path path = keys.get(key);           if (path == null) {               return;           }                    for (WatchEvent<?> event : key.pollEvents()) {               WatchEvent.Kind kind = event.kind();               if (kind == OVERFLOW) {                   continue;               }                              // 目錄監視事件的上下文是文件名               WatchEvent<Path> evt = cast(event);               Path name = evt.context();               Path child = path.resolve(name);              System.out.format(new SimpleDateFormat("yyyy-MM-dd hh:mm:ss").format(new Date()) + "  %s|%s\n", event.kind().name(), child);               if(child.toFile().isDirectory() && event.kind().name().equals("ENTRY_CREATE")){//對於新增的文件夾以及其子文件夾也要加入監控               register(child);               registPath(child.toFile());              }          }              // 重置 key           boolean valid = key.reset();           if (!valid) {               keys.remove(key);               if (keys.isEmpty()) {                   return;               }           }          }     }                public static void main(String[] args) {       FileWatch fileWatch = new FileWatch();                    Path dir = Paths.get("D:\\test2\\");          try {           fileWatch.fileWatch(dir);          } catch (IOException | InterruptedException e) {              e.printStackTrace();          }      }  }