private static String path = "E:\\Kankan";
public static void getFile() throws FileNotFoundException, IOException{
 final Timer timer = new Timer();
 timer.schedule(new TimerTask() {
 public void run() { 
 WatchKey key;
 try {
 WatchService watchService = FileSystems.getDefault().newWatchService();
 Paths.get(path).register(watchService, StandardWatchEventKinds.ENTRY_CREATE);
   while (true) {
   File file = new File(path);//path為監(jiān)聽文件夾 
   File[] files = file.listFiles();
  System.out.println("等待圖片加載！");
   key = watchService.take();//沒有文件增加時，阻塞在這里
  for (WatchEvent<?> event : key.pollEvents()) { 
   String fileName = path+"\\"+event.context();
   System.out.println("增加文件的文件夾路徑"+fileName);
   File file1 = files[files.length-1];//獲取最新文件
   System.out.println(file1.getName());//根據(jù)后綴判斷
   url = uploadFile(file1,uploadAddres);//上傳服務器
  }if (!key.reset()) {
   break; //中斷循環(huán)
  }
  }
  }catch (Exception e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
  }
  }
 }, 2000 , 3000);//第一個數(shù)字2000表示，2000ms以后開啟定時器,第二個數(shù)字3000，表示3000ms后運行一次run 
 }

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.file.FileSystems;//阻塞式IO流jar包
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.sql.Timestamp;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;

/**
 * 將file文件上傳到指定dir文件夾中
 * @param file：待上傳文件
 * @param dir：指定路徑
 * @throws FileNotFoundException
 * @throws IOException
 */
final static String uploadAddres = System.getProperty("catalina.home")+"\\webapps\\TiaoZhanB\\uploadFile";
 public static String uploadFile(File file , String dir) throws FileNotFoundException, IOException {
 String imgURL = null;
 try {
  InputStream in = new FileInputStream(file);
  System.out.println("服務器路徑：" + dir);
  // 獲取文件名稱
  String fileName = file.getName();
  // 路徑和文件名丟進file對象里
  File uploadFile = new File(dir, fileName);
  // 輸出流
  OutputStream out = new FileOutputStream(uploadFile);
  // 設置文件大小1MB
  byte[] buffer = new byte[1024 * 1024];
  int length;
  // 用循環(huán)從流中讀取文件的大小
  while ((length = in.read(buffer)) > 0) {
   out.write(buffer, 0, length);
  }
  // 設置圖片標題和全路徑
  imgURL = "uploadFile/" + fileName;
  
  System.out.println("絕對路徑為"+imgURL);
  // 關閉輸入流輸出流，釋放內(nèi)存
  in.close();
  out.close();
  } catch (Exception e) {
  e.printStackTrace();
  }
  return imgURL;
 }