spring mvc 上传文件显示进度

package com.java.controller; import java.io.File; import java.io.IOException; import java.io.PrintWriter; import java.text.NumberFormat; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.stereotype.Controller; import org.springframework.ui.ModelMap; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.RequestParam; import org.springframework.web.bind.annotation.ResponseBody; import org.springframework.web.multipart.commons.CommonsMultipartFile; import com.java.bean.Progress; @Controller public class FileUploadController { @RequestMapping(value = "/upload", method = RequestMethod.POST) public String upload(HttpServletRequest request, @RequestParam("file") CommonsMultipartFile[] file, ModelMap model) { System.out.println("开始"); String path = request.getSession().getServletContext().getRealPath("upload"); for (int i = 0; i < file.length; i++) { String fileName = file[i].getOriginalFilename(); // String fileName = new Date().getTime()+".jpg"; System.out.println(path); File targetFile = new File(path, fileName); if (!targetFile.exists()) { targetFile.mkdirs(); } // 保存 try { file[i].transferTo(targetFile); } catch (Exception e) { e.printStackTrace(); } model.addAttribute("fileUrl", request.getContextPath() + "/upload/" + fileName); } return "result"; } @RequestMapping("getprogress") @ResponseBody public void getProgress(HttpServletRequest request, HttpServletResponse response) throws IOException { Progress progress = (Progress) request.getSession().getAttribute("status"); PrintWriter writer = response.getWriter(); System.err.println(progress); NumberFormat numberFormat = NumberFormat.getInstance(); // 设置精确到小数点后2位 numberFormat.setMaximumFractionDigits(2); String result = numberFormat .format((float) progress.getBytesRead() / (float) progress.getContentLength() * 100); writer.println(result + "%"); System.err.println(result + "%"); writer.flush(); writer.close(); } }