怎么样能够实现JS异步文件分片断点上传功能？

package com.fs.controller;import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.util.Iterator;
import java.util.Map;
import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import org.apache.commons.lang3.StringUtils;
import org.csource.ClientGlobal;
import org.csource.common.MyException;
import org.csource.fastdfs.FileInfo;
import org.csource.fastdfs.StorageClient;
import org.csource.fastdfs.TrackerClient;
import org.csource.fastdfs.TrackerServer;
import org.junit.Test;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisShardInfo;
import com.alibaba.fastjson.JSON;
import com.fs.entity.UploadedFileInfo;
import com.fs.util.UploadUtil;
/**
 * @author admin
 *
 * 2016年12月20日下午8:59:38
 */
@Controller
public class FastDFSUpLoadController {
 @Resource
 private UploadUtil uploadUtil;
 @RequestMapping(value = "v1/uploadSize", method = RequestMethod.POST)
 @ResponseBody
 public Long uploadSize(HttpServletRequest request) {
 String name = request.getParameter("name");
 Long size = Long.parseLong(request.getParameter("size"));
 try {
  JedisShardInfo jedisShardInfo = new JedisShardInfo("192.168.0.12");
  Jedis jedis = new Jedis(jedisShardInfo);
  String str = jedis.get(name);
  UploadedFileInfo uploadedFileInfo = null;
  // 如果首次上传，已上传大小为 0
  if (StringUtils.isEmpty(str)) {
  uploadedFileInfo = new UploadedFileInfo();
  jedis.set(name, JSON.toJSONString(uploadedFileInfo));
  jedis.close();
  return 0L;
  }
  uploadedFileInfo = JSON.parseObject(str, UploadedFileInfo.class);
  jedis.close();
  //已经全部上传
  if(size <= uploadedFileInfo.getSize()){
  System.out.println("上传完成");
  }
  //UploadUtil.getFileInfo(uploadedFileInfo.getFileId());
  return uploadedFileInfo.getSize();
 } catch (Exception e) {
  e.printStackTrace();
  return 0L;
 }
 }
 @RequestMapping(value = "v1/uploadFile", method = RequestMethod.POST)
 @ResponseBody
 public int upload(HttpServletRequest request) {
 // CommonsMultipartResolver resolver = new
 // CommonsMultipartResolver(request.getSession().getServletContext());
 MultipartHttpServletRequest multiRequest = (MultipartHttpServletRequest) request;
 Iterator<String> t = multiRequest.getFileNames();
 MultipartFile fileDetail = multiRequest.getFile(t.next());
 String name = request.getParameter("name");
 JedisShardInfo jedisShardInfo = new JedisShardInfo("192.168.0.12");
 Jedis jedis = new Jedis(jedisShardInfo);
 UploadedFileInfo uploadedFileInfo = JSON.parseObject(jedis.get(name), UploadedFileInfo.class);
 uploadedFileInfo.setFileName(name);
 String path = "d:/testUpload";
 File file = new File(path);
 if (!file.exists() && !file.isDirectory()) {
  boolean b = file.mkdirs();
 }
 RandomAccessFile randomFile = null;
 try {
  randomFile = new RandomAccessFile(path+"/"+name, "rw");
  randomFile.seek(randomFile.length());
  randomFile.write(fileDetail.getBytes());
  uploadedFileInfo.setLocalPath(path+"/"+name);
  uploadedFileInfo.setSize(randomFile.length());
 } catch (IOException e) {
  e.printStackTrace();
 }finally{
  try {
  randomFile.close();
  } catch (IOException e) {
  e.printStackTrace();
  }
 }
 // 将上传文件信息保存到redis
 jedis.set(name, JSON.toJSONString(uploadedFileInfo));
 jedis.close();
 return 0;
 }
}