@MultipartConfig

This section contains detailed description of @MultipartConfig annotation and its implementation with sample code.

The annotation @MultipartConfig is used to handle multipart/form-data requests of Servlet.

Using this annotation(@MultipartConfig) you can set the temporary storage directory, maximum size limit of total parts, threshold size after which it starts storing it permanently.

@MultipartConfig has following attributes :

Attribute	Description
location	This attribute is used to set the location where files will be stored. You can also use it as temporary storage.
maxFileSize	Used for setting maximum size for file uploading. Default is -1L means unlimited.
maxRequestSize	This attribute describe the multipart/form-data requests' maximum size.
fileSizeThreshold	This attribute describe the threshold(size limit) after which the file will be stored/ written on disk.

The tools and technology used in the example is given below :

Eclipse Helios 3.6.1
Tomcat 7
jdk1.6.0_18

EXAMPLE

In the below example, we are going to store / upload the file on disk using Servlet having @MultipartConfig annotation which makes Servlet capable of handling multipart/form-data requests :

UploadFile.html

<!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>
<h3>@MultipartConfig Annotation Example</h3>
<FORM action="FileUpload" enctype="multipart/form-data" method="POST">
	File Name: &nbsp;&nbsp;&nbsp;<INPUT type="text" name="filename"><br/>
	Upload File: &nbsp;<INPUT type="file" name="content"><br/> 
	<INPUT type="submit" value="Submit">
</FORM>
</body>
</html>

FileUpload.java

package roseindia;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(name = "FileUpload", urlPatterns = { "/FileUpload" })
@MultipartConfig(location = "C:\\tmp", fileSizeThreshold = 1024 * 1024, maxFileSize = 1024 * 1024 * 5, maxRequestSize = 1024 * 1024 * 5 * 5)
public class FileUpload extends HttpServlet {
	public void service(HttpServletRequest req, HttpServletResponse resp)
	throws ServletException, IOException {
	String filename=req.getParameter("filename");
	// File will be moved from location to target directory
	req.getPart("content").write("C:/data/"+filename+".txt");
	if(req.getPart("content")!=null){
	PrintWriter out = resp.getWriter();
	out.write("<h3>File uploaded successfully</h3>");
	}
	}
}

OUTPUT

When you run the HTML page, you will get the following form for uploading file :

When you upload the file, you will get the following page :

In data folder, you will get the following file (which you gave name email) :

Download Source Code

@MultipartConfig