In this blog, we will discuss File Uploading in JSP. A JSP can be used with an HTML form tag to allow users to upload files to the server. An uploaded file can be a text file or a binary or an image file or just any document.

Creating a File Upload Form

Let us now understand how to create a file upload form. The following HTML code creates an uploader form. Following are the important points to be noted down −

The form method attribute should be set to POST method and GET method can not be used.
The form enctype attribute should be set to multipart/form-data.
The form action attribute should be set to a JSP file which would handle file uploading at backend server. Following example is using uploadFile.jsp program file to upload file.
To upload a single file you should use a single <input …/> tag with attribute type = “file”. To allow multiple files uploading, include more than one input tag with different values for the name attribute. The browser associates a Browse button with each of them.

<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>

This will display the following result. You can now select a file from the local PC and when the user clicks "Upload File", the form gets submitted along with the selected file −

File Upload −

Select a file to upload −

NOTE − Above form is just dummy form and would not work, you should try above code at your machine to make it work.

Writing Backend JSP Script

Let us now define a location where the uploaded files will be stored. You can hard code this in your program or this directory name can also be added using an external configuration such as a context-param element in web.xml as follows −

<web-app>

….

<context-param>

<description>Location to store uploaded file</description>

<param-name>file-upload</param-name>

<param-value>

      c:\apache-tomcat-5.5.29\webapps\data\

</param-value>

</context-param>

....

</web-app>

Following is the source code for UploadFile.jsp. This can handle uploading of multiple files at a time. Let us now consider the following before proceeding with the uploading of files.

The following example depends on FileUpload; make sure you have the latest version of commons-fileupload.x.x.jar file in your classpath. You can download it from https://commons.apache.org/fileupload/.
FileUpload depends on Commons IO; make sure you have the latest version of commons-io-x.x.jar file in your classpath. You can download it from https://commons.apache.org/io/.
While testing the following example, you should upload a file which is of less size than maxFileSize otherwise the file will not be uploaded.
Make sure you have created directories c:\temp and c:\apache-tomcat5.5.29\webapps\data well in advance.

<%@ page import = "java.io.*,java.util.*, javax.servlet.*" %>

<%@ page import = "javax.servlet.http.*" %>

<%@ page import = "org.apache.commons.fileupload.*" %>

<%@ page import = "org.apache.commons.fileupload.disk.*" %>

<%@ page import = "org.apache.commons.fileupload.servlet.*" %>

<%@ page import = "org.apache.commons.io.output.*" %>

<%

   File file ;

   int maxFileSize = 5000 * 1024;

   int maxMemSize = 5000 * 1024;

   ServletContext context = pageContext.getServletContext();

   String filePath = context.getInitParameter("file-upload");




   // 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("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>JSP File 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();

               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: " + filePath +

               fileName + "<br>");

            }

         }

         out.println("</body>");

         out.println("</html>");

      } catch(Exception ex) {

         System.out.println(ex);

      }

   } else {

      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>");

   }

%>

Now try to upload files using the HTML form which you created above. When you try http://localhost:8080/UploadFile.htm, it will display the following result. This will help you upload any file from your local machine.

File Upload −

Select a file to upload −

If your JSP script works fine, your file should be uploaded in c:\apache-tomcat5.5.29\webapps\data\ directory.

So, this brings us to the end of blog. This Tecklearn ‘File Uploading in JSP’ blog helps you with commonly asked questions if you are looking out for a job in Java Programming. If you wish to learn JSP and build a career Java Programming domain, then check out our interactive, Java and JEE Training, that comes with 24*7 support to guide you throughout your learning period. Please find the link for course details:

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