CODEWITHSUNDEEP
javajspservlets
Alex Naughton
Alex Naughton

Reputation: 165

How do I upload a file in Java using JSP's and Servlets?

I am creating a simple web app on my localhost. I have a form like so:

<form method="post" enctype="multipart/form-data" action="UploadFile">
    File:
    <input type="file" name="file" id="file" />
    Submit Button:
    <input type="submit" value="upload"/>
</form>

Not the exact form I have but you get the idea. UploadFile (i.e action = "UploadFile") is a Servlet. Now I know the path where I want the file to be uploaded to. For arguments sake, say the path is like:

String path = "Project\\web\\files\\";
//I want the file to be put into this folder.

So how do I deal with uploading a file which is on my Desktop at the moment to the path that I have just written.

I've been working with Java a while but have never done file uploading before. I looked at a few solutions online that seemed incredibly complex compared to how simple it is to deal with file uploading in other programming languages.

What is the best way to go about uploading this file.

Upvotes: 2

Views: 1037

Answers (1)

JRA
JRA

Reputation: 487

Add the below jar files

commons-collections-3.1.jar

commons-fileupload-1.2.2.jar

commons-io-2.1.jar

commons-logging-1.0.4.jar

Jsp Page

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
       pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>File Upload</title>
</head>
<body>
<form method="post" action="UploadServlet" enctype="multipart/form-data">
Select file to upload:
<input type="file" name="file" id="file"/><br/><br/>
<input type="submit" value="Upload" />
</form>
</body>
</html>

servlet code

package com.servlet;

import java.io.File;
import java.io.IOException;
import java.util.Iterator;
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.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

/**
 * Servlet implementation class UploadServlet
 */
public class UploadServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    private static final String DATA_DIRECTORY = "data";
    private static final int MAX_MEMORY_SIZE = 1024 * 1024 * 2;
    private static final int MAX_REQUEST_SIZE = 1024 * 1024;

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

        // Check that we have a file upload request
        boolean isMultipart = ServletFileUpload.isMultipartContent(request);

        if (!isMultipart) {
            return;
        }

        // Create a factory for disk-based file items
        DiskFileItemFactory factory = new DiskFileItemFactory();

        // Sets the size threshold beyond which files are written directly to
        // disk.
        factory.setSizeThreshold(MAX_MEMORY_SIZE);

        // Sets the directory used to temporarily store files that are larger
        // than the configured size threshold. We use temporary directory for
        // java
        factory.setRepository(new File(System.getProperty("java.io.tmpdir")));

        // constructs the folder where uploaded file will be stored
        String uploadFolder = getServletContext().getRealPath("")
                + File.separator + DATA_DIRECTORY;

        // Create a new file upload handler
        ServletFileUpload upload = new ServletFileUpload(factory);

        // Set overall request size constraint
        upload.setSizeMax(MAX_REQUEST_SIZE);

        try {
            // Parse the request
            List items = upload.parseRequest(request);
            Iterator iter = items.iterator();
            while (iter.hasNext()) {
                FileItem item = (FileItem) iter.next();

                if (!item.isFormField()) {
                    String fileName = new File(item.getName()).getName();
                    String filePath = uploadFolder + File.separator + fileName;
                    File uploadedFile = new File(filePath);
                    System.out.println(filePath);
                    // saves the file to upload directory
                    item.write(uploadedFile);
                }
            }

            // displays done.jsp page after upload finished
            getServletContext().getRequestDispatcher("/done.jsp").forward(
                    request, response);

        } catch (FileUploadException ex) {
            throw new ServletException(ex);
        } catch (Exception ex) {
            throw new ServletException(ex);
        }

    }

}

Your web.xml should be like this

 <servlet>
    <description></description>
    <display-name>UploadServlet</display-name>
    <servlet-name>UploadServlet</servlet-name>
    <servlet-class>com.servlet.UploadServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>UploadServlet</servlet-name>
    <url-pattern>/UploadServlet</url-pattern>
  </servlet-mapping>

Upvotes: 2

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