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Making a project and need file upload. So, i am using enctype="multipart/form-data" inform.

But i unable to parse parameters from request. I also tried getPart but it returning blank string.

Servlet code -->

import java.io.File; import java.io.IOException; import java.io.PrintWriter; import java.util.List; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.fileupload.FileItem; import org.apache.commons.fileupload.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; public class upload_wall extends HttpServlet { private static final long serialVersionUID = 1L; // location to store file uploaded private static final String UPLOAD_DIRECTORY = "image_upload"; // upload settings private static final int MEMORY_THRESHOLD = 1024 * 1024 * 3; // 3MB private static final int MAX_FILE_SIZE = 1024 * 1024 * 40; // 40MB private static final int MAX_REQUEST_SIZE = 1024 * 1024 * 50; // 50MB protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); // checks if the request actually contains upload file if (!ServletFileUpload.isMultipartContent(request)) { // if not, we stop here PrintWriter writer = response.getWriter(); writer.println("Error: Form must has enctype=multipart/form-data."); writer.flush(); return; } // configures upload settings DiskFileItemFactory factory = new DiskFileItemFactory(); // sets memory threshold - beyond which files are stored in disk factory.setSizeThreshold(MEMORY_THRESHOLD); // sets temporary location to store files factory.setRepository(new File(System.getProperty("java.io.tmpdir"))); ServletFileUpload upload = new ServletFileUpload(factory); // sets maximum size of upload file upload.setFileSizeMax(MAX_FILE_SIZE); // sets maximum size of request (include file + form data) upload.setSizeMax(MAX_REQUEST_SIZE); // constructs the directory path to store upload file // this path is relative to application's directory String uploadPath = getServletContext().getRealPath("") + File.separator + UPLOAD_DIRECTORY; // creates the directory if it does not exist File uploadDir = new File(uploadPath); if (!uploadDir.exists()) { uploadDir.mkdir(); } try { @SuppressWarnings("unchecked") List<FileItem> formItems = upload.parseRequest(request); String fileName1 = ""; if (formItems != null && formItems.size() > 0) { for (FileItem item : formItems) { // processes only fields that are not form fields if (!item.isFormField()) { String fileName = new File(item.getName()).getName(); fileName1 += fileName; String filePath = uploadPath + File.separator + fileName; File storeFile = new File(filePath); // saves the file on disk item.write(storeFile); } } } String p_text = request.getParameter("p_data"); String gallery_nm = request.getParameter("upload_wall_gallery"); out.println(p_text); out.println(gallery_nm); //out.println("Upload has been done successfully!"+fileName1); } catch (Exception ex) { out.println(ex.getMessage()); } } }

I unable to find a working example on net or stackoverflow.

Any simple solution?

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2 Answers 2

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25

The problem is here:

String p_text = request.getParameter("p_data"); String gallery_nm = request.getParameter("upload_wall_gallery");

From How to upload files to server using JSP/Servlet? answer, you should get your parameters as FileItem which isFormField() methods returns true. Posting the relevant code fragment from the answer:

for (FileItem item : formItems) { if (item.isFormField()) { // Process regular form field (input type="text|radio|checkbox|etc", select, etc). String fieldname = item.getFieldName(); String fieldvalue = item.getString(); // ... (do your job here) } else { // Process form file field (input type="file"). String fieldname = item.getFieldName(); String filename = FilenameUtils.getName(item.getName()); InputStream filecontent = item.getInputStream(); // ... (do your job here) } }

Solution: move your other request parameters handling to the else section when calling if (!item.isFormField()).

for (FileItem item : formItems) { // processes only fields that are not form fields if (!item.isFormField()) { String fileName = new File(item.getName()).getName(); fileName1+=fileName; String filePath = uploadPath + File.separator + fileName; File storeFile = new File(filePath); // saves the file on disk item.write(storeFile); } else { //here... String fieldname = item.getFieldName(); String fieldvalue = item.getString(); if (fieldname.equals("p_data")) { //logic goes here... } else if (fieldname.equals("upload_wall_gallery")) { //next logic goes here... } } }
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@LovepreetSinghBatth since you're new here, please mark this post as an answer by clicking on the check below the reputation.
4

Since its a multipart/form-data form a call to request.getParameter() will always return null. In this case what you have to do is 

 if (item.isFormField()) { System.out.println("Got a form field: " + item.getFieldName()+ " " +item.getString()); } else { // it is a file process, the way you are doing it }

I hope every thing should work fine.

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You can accept and up vote this answer if it worked for you. It will help future users :).

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