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Table of content:

1. Creating e-mail utility class
2. Creating e-mail form in JSP
3. Writing servlet for sending e-mail
4. Configuring SMTP server
5. Writing result page
6. Test the application
7. Download the application as Eclipse project

This tutorial is for building a simple web application for sending e-mail message using the key technologies in Java EE platform: JSP, Servlet and JavaMail. The following diagram describes workflow of the application:

Code in this tutorial is applied for Servlet 3.0, any version of JSP and JavaMail 1.4. The application can be deployed on any servlet container that supports Servlet 3.0 API such as Tomcat 7.0. The only external library required is JavaMail. If you are new to JavaMail, the following articles would be helpful:

- How to start e-mail programming in Java for how to download and use JavaMail.
- Send e-mail in plain text using JavaMail for how to write code to send a simple e-mail message.

NOTE: this tutorial is supposing you are already familiar with Java web application development, i.e. how to build, deploy and run an application with a servlet container like Tomcat.

Okay, let’s build the application now.

1. Creating e-mail utility class

Based on the article Send e-mail in plain text using JavaMail we write a utility class called EmailUtility.java as follows:

package net.codejava.email;

import java.util.Date;

import java.util.Properties;

import javax.mail.Authenticator;

import javax.mail.Message;

import javax.mail.MessagingException;

import javax.mail.PasswordAuthentication;

import javax.mail.Session;

import javax.mail.Transport;

import javax.mail.internet.AddressException;

import javax.mail.internet.InternetAddress;

import javax.mail.internet.MimeMessage;

/**

 * A utility class for sending e-mail messages

 * @author www.codejava.net

 *

 */

public class EmailUtility {

    public static void sendEmail(String host, String port,

            final String userName, final String password, String toAddress,

            String subject, String message) throws AddressException,

            MessagingException {

        // sets SMTP server properties

        Properties properties = new Properties();

        properties.put("mail.smtp.host", host);

        properties.put("mail.smtp.port", port);

        properties.put("mail.smtp.auth", "true");

        properties.put("mail.smtp.starttls.enable", "true");

        // creates a new session with an authenticator

        Authenticator auth = new Authenticator() {

            public PasswordAuthentication getPasswordAuthentication() {

                return new PasswordAuthentication(userName, password);

            }

        };

        Session session = Session.getInstance(properties, auth);

        // creates a new e-mail message

        Message msg = new MimeMessage(session);

        msg.setFrom(new InternetAddress(userName));

        InternetAddress[] toAddresses = { new InternetAddress(toAddress) };

        msg.setRecipients(Message.RecipientType.TO, toAddresses);

        msg.setSubject(subject);

        msg.setSentDate(new Date());

        msg.setText(message);

        // sends the e-mail

        Transport.send(msg);

    }

}

The class has one static method, sendEmail() – which takes SMTP server settings and message details as its arguments. We will put SMTP server settings in web.xml file of the application.

Remember to put mail.jar file of JavaMail into WEB-INF/lib directory.

2. Creating e-mail form in JSP

A form for sending an e-mail message would contain the following fields at least:

- Recipient address: text field.
- Subject: text field.
- Content: text area.

Create a new JSP file called EmailForm.jsp and put the following content:

<%@ 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>Send an e-mail</title>

</head>

<body>

    <form action="EmailSendingServlet" method="post">

        <table border="0" width="35%" align="center">

            <caption><h2>Send New E-mail</h2></caption>

            <tr>

                <td width="50%">Recipient address </td>

                <td><input type="text" name="recipient" size="50"/></td>

            </tr>

            <tr>

                <td>Subject </td>

                <td><input type="text" name="subject" size="50"/></td>

            </tr>

            <tr>

                <td>Content </td>

                <td><textarea rows="10" cols="39" name="content"></textarea> </td>

            </tr>

            <tr>

                <td colspan="2" align="center"><input type="submit" value="Send"/></td>

            </tr>

        </table>

    </form>

</body>

</html>

The form will look like this in a web browser:

Note that the attribute action of the form is pointing to URL of a servlet which will be created next. On submitting this form, the servlet is called for processing.

3. Writing servlet for sending e-mail

Now we implement a servlet that does the following tasks:

- Read SMTP server settings from web.xml file.
- Take input from EmailForm.jsp page.
- Invoke the EmailUtility class to send an e-mail message.
- Return a response to the user.

And following is code of the servlet:

package net.codejava.email;

import java.io.IOException;

import javax.servlet.ServletContext;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

/**

 * A servlet that takes message details from user and send it as a new e-mail

 * through an SMTP server.

 *

 * @author www.codejava.net

 *

 */

@WebServlet("/EmailSendingServlet")

public class EmailSendingServlet extends HttpServlet {

    private String host;

    private String port;

    private String user;

    private String pass;

    public void init() {

        // reads SMTP server setting from web.xml file

        ServletContext context = getServletContext();

        host = context.getInitParameter("host");

        port = context.getInitParameter("port");

        user = context.getInitParameter("user");

        pass = context.getInitParameter("pass");

    }

    protected void doPost(HttpServletRequest request,

            HttpServletResponse response) throws ServletException, IOException {

        // reads form fields

        String recipient = request.getParameter("recipient");

        String subject = request.getParameter("subject");

        String content = request.getParameter("content");

        String resultMessage = "";

        try {

            EmailUtility.sendEmail(host, port, user, pass, recipient, subject,

                    content);

            resultMessage = "The e-mail was sent successfully";

        } catch (Exception ex) {

            ex.printStackTrace();

            resultMessage = "There were an error: " + ex.getMessage();

        } finally {

            request.setAttribute("Message", resultMessage);

            getServletContext().getRequestDispatcher("/Result.jsp").forward(

                    request, response);

        }

    }

}

As we can see, the servlet, EmailSendingServlet - loads configuration for SMTP server upon initialization in its init()method, and handles user’s requests in the doPost() method. It reads message details (recipient, subject and content) from EmailForm.jsp page and tries to sending the e-mail by invoking the sendEmail() method of the EmailUtilityclass. The users will finally receives a Result.jsp page which tells them whether the e-mail was sent or not.

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4. Configuring SMTP server

We configure the settings for SMTP server in the web deployment descriptor file (web.xml) as follows:

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xmlns="http://java.sun.com/xml/ns/javaee"

    xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"

    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee

        http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"

    id="WebApp_ID" version="3.0">

    <display-name>EmailSendingWebApp</display-name>

    <!-- SMTP settings -->

    <context-param>

        <param-name>host</param-name>

        <param-value>smtp.gmail.com</param-value>

    </context-param>

    <context-param>

        <param-name>port</param-name>

        <param-value>587</param-value>

    </context-param>

    <context-param>

        <param-name>user</param-name>

        <param-value>YOUR_EMAIL</param-value>

    </context-param>

    <context-param>

        <param-name>pass</param-name>

        <param-value>YOUR_PASSWORD</param-value>

    </context-param>

    <welcome-file-list>

        <welcome-file>EmailForm.jsp</welcome-file>

    </welcome-file-list>

</web-app>

The SMTP settings are configured as context parameters. In this application, we use a Gmail’s SMTP account, and you should change the sender e-mail address (user) and password to match your account setting. Check your e-mail service provider to make sure SMTP is enabled for your account.

Since we use Servlet 3.0 API, the servlet declaration and mapping does not require in this web.xml file. And the EmailForm.jsp is set as default page in the <welcome-file-list> section.

5. Writing result page

Code of the Result.jsp page is as simple as follows:

<%@ 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>Result</title>

</head>

<body>

    <center>

        <h3><%=request.getAttribute("Message")%></h3>

    </center>

</body>

</html>

It simply displays a message which is sent from the servlet through an attribute named Message.

6. Test the application

Supposing the application is packaged as EmailSendingWebApp.war and is deployed on Tomcat server on localhost at port 8080. Type the following URL in your web browser:

http://localhost:8080/EmailSendingWebApp/

A form is displayed for entering message details. Type some information into the fields: