How to Upload CSV Files using Apache FileUpload/CSV

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This article represents code samples on how to use Apache Commons FileUpload and Apache Commons CSV libraries to upload CSV file using Java Servlet. Please feel free to comment/suggest if I missed to mention one or more important points. Also, sorry for the typos.

 

Code Samples – Java Code

Following is the code for Java Servlet.

package com.vitalflux.core;

import java.io.IOException;
import java.io.StringReader;
import java.util.List;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVRecord;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

public class FileIOController extends HttpServlet {

	private static final long serialVersionUID = 1L;

	protected void doPost(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		if (ServletFileUpload.isMultipartContent(request)) {
			try {
				List multiparts = new ServletFileUpload(
						new DiskFileItemFactory()).parseRequest(request);
				for (FileItem item : multiparts) {
					//
					// If the item is a string content
					//
					if (!item.isFormField()) {
						String content = item.getString();
						StringReader sReader = new StringReader(content);
						//
						// Reads the file with headers as First Name and Last Name
						//
						Iterable records = CSVFormat.RFC4180
								.withFirstRecordAsHeader().parse(sReader);
						//
						// Iterate over different rows
						//
						for (CSVRecord record : records) {
							String lastName = record.get("Last Name");
							String firstName = record.get("First Name");
							System.out.println("First Name: " + firstName
									+ ", Last Name: " + lastName);
						}
					}
				}
				// File uploaded successfully
				request.setAttribute("message", "File Uploaded Successfully");
			} catch (Exception ex) {
				request.setAttribute("message", "File Upload Failed due to "
						+ ex);
			}
		} else {
			request.setAttribute("message",
					"Sorry this Servlet only handles file upload request");
		}
		//
		// Redirects the response to JSP page
		//
		RequestDispatcher dispatcher=getServletContext().getRequestDispatcher( "/WEB-INF/views/upload.jsp" );
		dispatcher.forward(request, response);
	}
}

Code Samples – Web.xml

Following is the code which one would want to define in web.xml. This defines configuration for above given servlet.

<servlet>
    <servlet-name>fileIOController</servlet-name>
    <servlet-class>com.vitalflux.core.FileIOController</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>fileIOController</servlet-name>
    <url-pattern>/vitalflux/uploadfile</url-pattern>
  </servlet-mapping>

 

Code Samples – UI Code

Following is the UI code. Note down the enctype=”multipart/form-data” within Form tag.

<!DOCTYPE html>
<html>
<title>Upload File</title>
<head>
<!-- Mobile Specific Meta -->	
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
	<!--[if IE]><meta http-equiv='X-UA-Compatible' content='IE=edge,chrome=1'><![endif]-->

    <!-- Bootstrap -->
    <link href="/assets/css/bootstrap.css" rel="stylesheet">
</head>
<body class="container">
<h1>Upload the file</h1>
<hr/>
<div>
<form action="/vitalflux/uploadfile" method="post"  enctype="multipart/form-data">
          <div class="form-group">
            <label for="file" class="control-label">File</label>
            <input type="file" class="form-control" name="file" id="file" placeholder="Select a file" required>
          </div>
          <div class="modal-footer">			          	
	        <button ng-if="showSubmit" class="btn btn-primary" type="submit">Submit</button>
	      </div>       	         
</form>
</div>	
<script src="/assets/js/jquery.min.js"></script>
<!-- Include all compiled plugins (below), or include individual files as needed -->
<script src="/assets/js/bootstrap.min.js"></script>
</body>
</html>

 

Ajitesh Kumar

Ajitesh Kumar

Ajitesh is passionate about various different technologies including programming languages such as Java/JEE, Javascript, PHP, .NET, C/C++, mobile programming languages etc and, computing fundamentals such as application security, cloud computing, API, mobile apps, google glass, big data etc.Recently, he has been digging deep into the field of data science and machine learning.

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