Convert Blob to Wav File

Question

I am uploading a wav file from Chrome using Javascript as seen on Saving WAV File Recorded in Chrome to Server. I am using java for my backend and I followed this topic Sending a blob to a servlet through ajax. The file was successfully created.However it seems to be damaged and can not be read. I am wondering how to properly make a wav file.

Send the blob using ajax:

 var xhr = new XMLHttpRequest();
  xhr.onload = function (e) {
      if (this.readyState === 4) {
          console.log("Server returned: ", e.target.responseText);
      }
  };
  var fd = new FormData();
  fd.append("Wav", blob);
  xhr.open("POST", "servletUrl", true);
  xhr.send(fd);

The java code :

protected void doPost(HttpServletRequest request,
        HttpServletResponse response) throws ServletException, IOException {
    try {

        byte[] buffer = new byte[1024 * 1024];
        InputStream input = request.getInputStream();       
        OutputStream output = new FileOutputStream("G:\\test.wav");
        int bytesRead;
        while ((bytesRead = input.read(buffer)) != -1){
            System.out.println(bytesRead);
            output.write(buffer, 0, bytesRead);
        }
        output.close();
        input.close();

    } catch (Exception e) {
        e.printStackTrace();
    }

}