How to HttpServletRequest file objects and store them

Core code

Because HttpServletRequest cannot directly fetch the file data, it is cast to MultipartHttpServletRequest

MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;
List < MultipartFile > files = multipartRequest.getFiles("files");

POST

/* Submit a form */
function myupload() {
  $.ajax({
    url:"/exUploadController.do?uploadTest",
    type : "POST",
    async: false,
    cache: false, // Set here false
    contentType: false,// You must set false ,formupload1 You must set the enctype="multipart/form-data"
    processData: false, // You must set fals
    data :new FormData(document.getElementById("myForm")),
    success:function (data) {
      alert(data);
    },
    error:function (XMLHttpRequest, textStatus, errorThrown) {
      console.log(XMLHttpRequest);
      console.log(textStatus);
      console.log(errorThrown);
    }
  })
}

Servlet

	HttpServletRequest request;
  　　　　 　　 // Get uploaded pictures 
      MultipartHttpServletRequest mureq = (MultipartHttpServletRequest) request;
      Map<String, MultipartFile> files = mureq.getFileMap(); 
      MultipartFile file =null;
      if (files != null &&files.size()> 0) { 
        
        Map.Entry<String, MultipartFile> f = files.entrySet().iterator().next(); 
        file = f.getValue();
      } 

  　　　　 　　 // Get the path of project deployment 

  　　　　 　　 String rootPath = request.getSession().getServletContext().getRealPath("/");

 　　　　  // Get the name of the uploaded picture 
  　　　　 　　 String fileName = file.getOriginalFilename();

  　　　　 　　 

 　　　　  // Gets the size of the uploaded picture 
  　　　　 　　 float size = file.getSize()

  　　　　 　　 // In path Create under the path 1 Files 

  　　　　 　　 File newFile = new File(path);

  　　　　 　　 // Determine whether the file exists 
  　　　　 　　 if(!newFile.exists()) {
   　　　　 　　 　　 newFile.mkdirs();// If it doesn't exist, open up 1 Individual space 
  　　　　 　　 }
  　　　　 　　 // Store uploaded files 
  　　　　 　　 file.transferTo(newFile);