Styjun

If you happen to use Spring MVC, this is how to:
(I'm leaving this here in case someone find it useful).

Use a form with enctype attribute set to "multipart/form-data" (Same as BalusC's Answer)

<form action="upload" method="post" enctype="multipart/form-data">
 <input type="file" name="file" />
 <input type="submit" value="Upload"/>
</form>

In your controller, map the request parameter file to MultipartFile type as follows:

@RequestMapping(value = "/upload", method = RequestMethod.POST)
public void handleUpload(@RequestParam("file") MultipartFile file) throws IOException 
 if (!file.isEmpty()) 
 byte[] bytes = file.getBytes(); // alternatively, file.getInputStream();
 // application logic
 

You can get the filename and size using MultipartFile's getOriginalFilename() and getSize().

I've tested this with Spring version 4.1.1.RELEASE.

You need the common-io.1.4.jar file to be included in your lib directory, or if you're working in any editor, like NetBeans, then you need to go to project properties and just add the JAR file and you will be done.

To get the common.io.jar file just google it or just go to the Apache Tomcat website where you get the option for a free download of this file. But remember one thing: download the binary ZIP file if you're a Windows user.

I am Using common Servlet for every Html Form whether it has attachments or not.
This Servlet returns a TreeMap where the keys are jsp name Parameters and values are User Inputs and saves all attachments in fixed directory and later you rename the directory of your choice.Here Connections is our custom interface having connection object. I think this will help you

public class ServletCommonfunctions extends HttpServlet implements
 Connections 

 private static final long serialVersionUID = 1L;

 public ServletCommonfunctions() 

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

 public SortedMap<String, String> savefilesindirectory(
 HttpServletRequest request, HttpServletResponse response)
 throws IOException 
 // Map<String, String> key_values = Collections.synchronizedMap( new
 // TreeMap<String, String>());
 SortedMap<String, String> key_values = new TreeMap<String, String>();
 String dist = null, fact = null;
 PrintWriter out = response.getWriter();
 File file;
 String filePath = "E:\FSPATH1\2KL06CS048\";
 System.out.println("Directory Created ????????????"
 + new File(filePath).mkdir());
 int maxFileSize = 5000 * 1024;
 int maxMemSize = 5000 * 1024;
 // Verify the content type
 String contentType = request.getContentType();
 if ((contentType.indexOf("multipart/form-data") >= 0)) 
 DiskFileItemFactory factory = new DiskFileItemFactory();
 // maximum size that will be stored in memory
 factory.setSizeThreshold(maxMemSize);
 // Location to save data that is larger than maxMemSize.
 factory.setRepository(new File(filePath));
 // Create a new file upload handler
 ServletFileUpload upload = new ServletFileUpload(factory);
 // maximum file size to be uploaded.
 upload.setSizeMax(maxFileSize);
 try 
 // Parse the request to get file items.
 @SuppressWarnings("unchecked")
 List<FileItem> fileItems = upload.parseRequest(request);
 // Process the uploaded file items
 Iterator<FileItem> i = fileItems.iterator();
 while (i.hasNext()) 
 FileItem fi = (FileItem) i.next();
 if (!fi.isFormField()) 
 // Get the uploaded file parameters
 String fileName = fi.getName();
 // Write the file
 if (fileName.lastIndexOf("\") >= 0) 
 file = new File(filePath
 + fileName.substring(fileName
 .lastIndexOf("\")));
 else 
 file = new File(filePath
 + fileName.substring(fileName
 .lastIndexOf("\") + 1));
 
 fi.write(file);
 else 
 key_values.put(fi.getFieldName(), fi.getString());
 
 
 catch (Exception ex) 
 System.out.println(ex);
 
 
 return key_values;
 

Without component or external Library in Tomcat 6 o 7

Enabling Upload in the web.xml file:

http://joseluisbz.wordpress.com/2014/01/17/manually-installing-php-tomcat-and-httpd-lounge/#Enabling%20File%20Uploads.

<servlet>
 <servlet-name>jsp</servlet-name>
 <servlet-class>org.apache.jasper.servlet.JspServlet</servlet-class>
 <multipart-config>
 <max-file-size>3145728</max-file-size>
 <max-request-size>5242880</max-request-size>
 </multipart-config>
 <init-param>
 <param-name>fork</param-name>
 <param-value>false</param-value>
 </init-param>
 <init-param>
 <param-name>xpoweredBy</param-name>
 <param-value>false</param-value>
 </init-param>
 <load-on-startup>3</load-on-startup>
</servlet>

AS YOU CAN SEE:

 <multipart-config>
 <max-file-size>3145728</max-file-size>
 <max-request-size>5242880</max-request-size>
 </multipart-config>

Uploading Files using JSP. Files:

In the html file

<form method="post" enctype="multipart/form-data" name="Form" >

 <input type="file" name="fFoto" id="fFoto" value="" /></td>
 <input type="file" name="fResumen" id="fResumen" value=""/>

In the JSP File or Servlet

 InputStream isFoto = request.getPart("fFoto").getInputStream();
 InputStream isResu = request.getPart("fResumen").getInputStream();
 ByteArrayOutputStream baos = new ByteArrayOutputStream();
 byte buf[] = new byte[8192];
 int qt = 0;
 while ((qt = isResu.read(buf)) != -1) 
 baos.write(buf, 0, qt);
 
 String sResumen = baos.toString();

Edit your code to servlet requirements, like max-file-size, max-request-size and other options that you can to set...

For Spring MVC
I have been trying for hours to do this
and managed to have a simpler version that worked for taking form input both data and image.

<form action="/handleform" method="post" enctype="multipart/form-data">
 <input type="text" name="name" />
 <input type="text" name="age" />
 <input type="file" name="file" />
 <input type="submit" />
</form>

Controller to handle

@Controller
public class FormController 
 @RequestMapping(value="/handleform",method= RequestMethod.POST)
 ModelAndView register(@RequestParam String name, @RequestParam int age, @RequestParam MultipartFile file)
 throws ServletException, IOException 

 System.out.println(name);
 System.out.println(age);
 if(!file.isEmpty())
 byte[] bytes = file.getBytes();
 String filename = file.getOriginalFilename();
 BufferedOutputStream stream =new BufferedOutputStream(new FileOutputStream(new File("D:/" + filename)));
 stream.write(bytes);
 stream.flush();
 stream.close();
 
 return new ModelAndView("index");
 

Hope it helps :)

Another source of this problem occurs if you are using Geronimo with its embedded Tomcat. In this case, after many iterations of testing commons-io and commons-fileupload, the problem arises from a parent classloader handling the commons-xxx jars. This has to be prevented. The crash always occurred at:

fileItems = uploader.parseRequest(request);

Note that the List type of fileItems has changed with the current version of commons-fileupload to be specifically List<FileItem> as opposed to prior versions where it was generic List.

I added the source code for commons-fileupload and commons-io into my Eclipse project to trace the actual error and finally got some insight. First, the exception thrown is of type Throwable not the stated FileIOException nor even Exception (these will not be trapped). Second, the error message is obfuscatory in that it stated class not found because axis2 could not find commons-io. Axis2 is not used in my project at all but exists as a folder in the Geronimo repository subdirectory as part of standard installation.

Finally, I found 1 place that posed a working solution which successfully solved my problem. You must hide the jars from parent loader in the deployment plan. This was put into geronimo-web.xml with my full file shown below.

Pasted from <http://osdir.com/ml/user-geronimo-apache/2011-03/msg00026.html> 



<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<web:web-app xmlns:app="http://geronimo.apache.org/xml/ns/j2ee/application-2.0" xmlns:client="http://geronimo.apache.org/xml/ns/j2ee/application-client-2.0" xmlns:conn="http://geronimo.apache.org/xml/ns/j2ee/connector-1.2" xmlns:dep="http://geronimo.apache.org/xml/ns/deployment-1.2" xmlns:ejb="http://openejb.apache.org/xml/ns/openejb-jar-2.2" xmlns:log="http://geronimo.apache.org/xml/ns/loginconfig-2.0" xmlns:name="http://geronimo.apache.org/xml/ns/naming-1.2" xmlns:pers="http://java.sun.com/xml/ns/persistence" xmlns:pkgen="http://openejb.apache.org/xml/ns/pkgen-2.1" xmlns:sec="http://geronimo.apache.org/xml/ns/security-2.0" xmlns:web="http://geronimo.apache.org/xml/ns/j2ee/web-2.0.1">
 <dep:environment>
 <dep:moduleId>
 <dep:groupId>DataStar</dep:groupId>
 <dep:artifactId>DataStar</dep:artifactId>
 <dep:version>1.0</dep:version>
 <dep:type>car</dep:type>
 </dep:moduleId>

<!--Don't load commons-io or fileupload from parent classloaders-->
 <dep:hidden-classes>
 <dep:filter>org.apache.commons.io</dep:filter>
 <dep:filter>org.apache.commons.fileupload</dep:filter>
 </dep:hidden-classes>
 <dep:inverse-classloading/> 


 </dep:environment>
 <web:context-root>/DataStar</web:context-root>
</web:web-app>

Here's an example using apache commons-fileupload:

// apache commons-fileupload to handle file upload
DiskFileItemFactory factory = new DiskFileItemFactory();
factory.setRepository(new File(DataSources.TORRENTS_DIR()));
ServletFileUpload fileUpload = new ServletFileUpload(factory);

List<FileItem> items = fileUpload.parseRequest(req.raw());
FileItem item = items.stream()
 .filter(e ->
 "the_upload_name".equals(e.getFieldName()))
 .findFirst().get();
String fileName = item.getName();

item.write(new File(dir, fileName));
log.info(fileName);

you can upload file using jsp /servlet.

<form action="UploadFileServlet" method="post">
 <input type="text" name="description" />
 <input type="file" name="file" />
 <input type="submit" />
</form>

on the other hand server side.
use following code.

 package com.abc..servlet;

import java.io.File;
---------
--------


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

 public UploadFileServlet() 
 super();
 // TODO Auto-generated constructor stub
 
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
 // TODO Auto-generated method stub
 response.sendRedirect("../jsp/ErrorPage.jsp");
 

 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
 // TODO Auto-generated method stub

 PrintWriter out = response.getWriter();
 HttpSession httpSession = request.getSession();
 String filePathUpload = (String) httpSession.getAttribute("path")!=null ? httpSession.getAttribute("path").toString() : "" ;

 String path1 = filePathUpload;
 String filename = null;
 File path = null;
 FileItem item=null;


 boolean isMultipart = ServletFileUpload.isMultipartContent(request);

 if (isMultipart) 
 FileItemFactory factory = new DiskFileItemFactory();
 ServletFileUpload upload = new ServletFileUpload(factory);
 String FieldName = "";
 try 
 List items = upload.parseRequest(request);
 Iterator iterator = items.iterator();
 while (iterator.hasNext()) 
 item = (FileItem) iterator.next();

 if (fieldname.equals("description")) 
 description = item.getString();
 
 
 if (!item.isFormField()) 
 filename = item.getName();
 path = new File(path1 + File.separator);
 if (!path.exists()) 
 boolean status = path.mkdirs();
 
 /* START OF CODE FRO PRIVILEDGE*/

 File uploadedFile = new File(path + Filename); // for copy file
 item.write(uploadedFile);
 
 else 
 f1 = item.getName();
 

 // END OF WHILE 
 response.sendRedirect("welcome.jsp");
 catch (FileUploadException e) 
 e.printStackTrace();
 catch (Exception e) 
 e.printStackTrace();
 
 
 }

}

DiskFileUpload upload=new DiskFileUpload();

From this object you have to get file items and fields then yo can store into server like followed:

String loc="./webapps/prjct name/server folder/"+contentid+extension;
File uploadFile=new File(loc);
item.write(uploadFile);

Sending multiple file for file we have to use enctype="multipart/form-data"

and to send multiple file use multiple="multiple" in input tag

<form action="upload" method="post" enctype="multipart/form-data">
 <input type="file" name="fileattachments" multiple="multiple"/>
 <input type="submit" />
</form>

HTML PAGE

<html>
<head>
<title>File Uploading Form</title>
</head>
<body>
<h3>File Upload:</h3>
Select a file to upload: <br />
<form action="UploadServlet" method="post"
 enctype="multipart/form-data">
<input type="file" name="file" size="50" />
<br />
<input type="submit" value="Upload File" />
</form>
</body>
</html> 

SERVLET FILE

// Import required java libraries
import java.io.*;
import java.util.*;

import javax.servlet.ServletConfig;
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;
import org.apache.commons.io.output.*;

public class UploadServlet extends HttpServlet 

 private boolean isMultipart;
 private String filePath;
 private int maxFileSize = 50 * 1024;
 private int maxMemSize = 4 * 1024;
 private File file ;

 public void init( )
 // Get the file location where it would be stored.
 filePath = 
 getServletContext().getInitParameter("file-upload"); 
 
 public void doPost(HttpServletRequest request, 
 HttpServletResponse response)
 throws ServletException, java.io.IOException 
 // Check that we have a file upload request
 isMultipart = ServletFileUpload.isMultipartContent(request);
 response.setContentType("text/html");
 java.io.PrintWriter out = response.getWriter( );
 if( !isMultipart )
 out.println("<html>");
 out.println("<head>");
 out.println("<title>Servlet upload</title>"); 
 out.println("</head>");
 out.println("<body>");
 out.println("<p>No file uploaded</p>"); 
 out.println("</body>");
 out.println("</html>");
 return;
 
 DiskFileItemFactory factory = new DiskFileItemFactory();
 // maximum size that will be stored in memory
 factory.setSizeThreshold(maxMemSize);
 // Location to save data that is larger than maxMemSize.
 factory.setRepository(new File("c:\temp"));

 // Create a new file upload handler
 ServletFileUpload upload = new ServletFileUpload(factory);
 // maximum file size to be uploaded.
 upload.setSizeMax( maxFileSize );

 try 
 // Parse the request to get file items.
 List fileItems = upload.parseRequest(request);

 // Process the uploaded file items
 Iterator i = fileItems.iterator();

 out.println("<html>");
 out.println("<head>");
 out.println("<title>Servlet upload</title>"); 
 out.println("</head>");
 out.println("<body>");
 while ( i.hasNext () ) 
 
 FileItem fi = (FileItem)i.next();
 if ( !fi.isFormField () ) 
 
 // Get the uploaded file parameters
 String fieldName = fi.getFieldName();
 String fileName = fi.getName();
 String contentType = fi.getContentType();
 boolean isInMemory = fi.isInMemory();
 long sizeInBytes = fi.getSize();
 // Write the file
 if( fileName.lastIndexOf("\") >= 0 )
 file = new File( filePath + 
 fileName.substring( fileName.lastIndexOf("\"))) ;
 else
 file = new File( filePath + 
 fileName.substring(fileName.lastIndexOf("\")+1)) ;
 
 fi.write( file ) ;
 out.println("Uploaded Filename: " + fileName + "<br>");
 
 
 out.println("</body>");
 out.println("</html>");
 catch(Exception ex) 
 System.out.println(ex);
 
 
 public void doGet(HttpServletRequest request, 
 HttpServletResponse response)
 throws ServletException, java.io.IOException 

 throw new ServletException("GET method used with " +
 getClass( ).getName( )+": POST method required.");
 

web.xml

Compile above servlet UploadServlet and create required entry in web.xml file as follows.

<servlet>
 <servlet-name>UploadServlet</servlet-name>
 <servlet-class>UploadServlet</servlet-class>
</servlet>

<servlet-mapping>
 <servlet-name>UploadServlet</servlet-name>
 <url-pattern>/UploadServlet</url-pattern>
</servlet-mapping>