!DOCTYPE html>
html lang="en">
head>
 meta charset="UTF-8">
 title>Ajax上传/title>
 script src="js/jquery-1.12.4.js">/script>
/head>
body>
 h1>文件上传/h1>
 form id="f" enctype="multipart/form-data">
  UserName:input type="text" name="userName">br/>
  File1:input type="file" name="file">br/>
  File2:input type="file" name="file">br/>
  input type="button" id="btn" value="提交">
 /form>
/body>
script>
 $(function () {
  $("#btn").on("click",function () {
   //使用FormData对象来提交整个表单，它支持文件的上传
   var formData=new FormData(document.getElementById("f"));
   //额外带来一些数据
   formData.append("age",14);
   //使用ajax提交
   $.ajax("ajaxUpload",{
    type:"post",
    data:formData,
    processData:false,//告诉jquery不要去处理请求的数据格式
    contentType:false,//告诉jquery不要设置请求头的类型
    success:function (data) {
     alert(data);
    }
   });
  })
 })
/script>
/html>

@WebServlet("/ajaxUpload")
@MultipartConfig //开启上传功能
/**
 * @author hh
 */
public class FileUploadServlet extends HttpServlet {
 @Override
 protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
  req.setCharacterEncoding("utf-8");
  //获取用户名
  String userName=req.getParameter("userName");
  //获取年龄
  String age=req.getParameter("age");
  System.out.println(userName);
  System.out.println(age);
  //获取项目部署的绝对路径
  String uploadPath=req.getServletContext().getRealPath("/photos");
  //构建上传的文件夹
  File dir=new File(uploadPath);
  if(!dir.exists()){
   dir.mkdir();
  }
  //获取所有上传的Part
  CollectionPart> parts= req.getParts();
  for (Part part:parts) {
   //判断上传的类型是否为空，如果为空则不执行上传
   if(part.getContentType()!=null){
    //获取文件名
    String fileName=part.getSubmittedFileName();
    //执行上传
    part.write(uploadPath+File.separator+fileName);
   }
  }
  //响应上传成功
  resp.getWriter().println("uplaod success");
 }
}