Java Kart: File Upload Example using Servlet

This article demonstrates the file upload example using JSP and Servlet. This example uses Commons FileUpload package which makes it easy to add robust, high-performance, file upload capability to your servlets and web applications. This example needs commons-fileupload-1.2.1.jar and commons-io-1.4.jar in the class path of your web application.

FileUpload parses HTTP requests, "Form-based File Upload in HTML". That is, if an HTTP request is submitted using the POST method, and with a content type of "multipart/form-data", then FileUpload can parse that request, and make the results available in a manner easily used by the caller.

uploadfile.jsp

<%@ 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>Insert title here</title>
</head>
<body>
 <form action="upload-file" method="post" name="uploadForm" enctype="multipart/form-data">
  <p>
   <input name="uploadfile" type="file" size="50">
  </p>

  <p> </p>
  <input name="submit" type="submit" value="Submit">
 </form>
</body>
</html>

web.xml

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  <display-name>Archetype Created Web Application</display-name>
  <servlet>
   <servlet-name>upload-file</servlet-name>
   <servlet-class>com.mycompany.mywebapp.FileUploadServlet</servlet-class>
  </servlet>
  <servlet-mapping>
   <servlet-name>upload-file</servlet-name>
   <url-pattern>/upload-file</url-pattern>
  </servlet-mapping>
</web-app>

FileUploadServlet.java

package com.mycompany.mywebapp;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
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.FileItemFactory;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

public class FileUploadServlet extends HttpServlet {
 @Override
 protected void doPost(HttpServletRequest request,
   HttpServletResponse response) throws ServletException, IOException {

  // Directory where files will be saved
  File seshdir = new File("c:\\servlet");

  if (!seshdir.exists()) {
   seshdir.mkdirs();
  }

  FileItemFactory factory = new DiskFileItemFactory();

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

  // Parse the request
  List items = null;
  try{
   items = upload.parseRequest(request);
  } catch (FileUploadException e) {
   throw new ServletException("Exception while uploading the file");
  }

  for (DiskFileItem diskFileItem : items) {
   // Exclude the form fields
   if (diskFileItem.isFormField()) {
    continue;
   }

   byte[] fileBytes = diskFileItem.get();
   File file = new File(seshdir, diskFileItem.getName());
   FileOutputStream fileOutputStream = new FileOutputStream(file);
   fileOutputStream.write(fileBytes);
   fileOutputStream.flush();
  }
 }
}

11 comments:

AnonymousJune 7, 2013 at 9:37 AM
// for (DiskFileItem diskFileItem : items)

in Compatible type
required: org.apache.commons.fileupload.disk.DiskFileItem
found: java.lang.Object
AnonymousJune 15, 2013 at 11:28 PM
i think it could be jar file problem

might be it is not located properly
AnonymousJuly 23, 2013 at 10:14 PM
FileUploadServlet.java:42: incompatible types
found : java.lang.Object
required: org.apache.commons.fileupload.disk.DiskFileItem
for (DiskFileItem diskFileItem : items) {
^
1 error
Compilation failed.
AnonymousAugust 21, 2013 at 1:09 PM
Looks like java 6 vs java 7 issue...
AnonymousOctober 7, 2013 at 9:34 AM
No its actually incompatible type
saritOctober 23, 2013 at 4:04 AM
Try using Iterator, worked for me

for (Iterator it = items.iterator(); it.hasNext();) {
DiskFileItem diskFileItem = (DiskFileItem) it.next();
if (diskFileItem.isFormField()) {
continue;
}
byte[] fileBytes = diskFileItem.get();
File file = new File(seshdir, diskFileItem.getName());
FileOutputStream fileOutputStream = new FileOutputStream(file);
fileOutputStream.write(fileBytes);
fileOutputStream.flush();
}
hassiniOctober 24, 2013 at 5:57 AM
it showing error at DiskFileItem diskFileItem : items ... in items (mismatch cant convert eleent type object to DiskFileItem
UnknownOctober 31, 2013 at 12:20 PM
which jar file shoul be added for this programe
AnonymousNovember 12, 2013 at 3:20 AM
what should be written in the servlet to get the the file input type in servlet from jsp
AnonymousNovember 18, 2013 at 11:48 PM
Add iterator to items and cast object to DiskFileItem:

for (Iterator it = items.iterator(); it.hasNext();) {
DiskFileItem diskFileItem = (DiskFileItem) it.next();