Java Smtp Server Example Code

The author voluntarily contributed this tutorial as a part of Pepipost Write to Contribute program.

Introduction

Sending Email is the most common and necessary requirement for most of the applications. Java provides Java Mail API - a platform and protocol independent framework to build mail and messaging applications.

The JavaMail reference implementation is licensed under the Common Development and Distribution License (CDDL) v1.1 and GNU General Public License (GPL) v2 with Classpath Exception.

In this guide, you will get detailed steps on how to setup JavaMail in your Java Project and implement JavaMail API to build and send emails on SMTP protocol.

Prerequisites

• Eclipse IDE
• Java Runtime Environment

Step 1 - Create new Maven Project

1. Click onFile > New > Project > Maven > Maven Project

1. SelectCreate a simple project(skip archetype selection) and clickFinish.

1. Give Artifact Id and group Id to your project.

1. This will give the default project structure as below:

1. A default pom.xml is created:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">    <modelVersion>4.0.0</modelVersion>    <groupId>SendEmail</groupId>    <artifactId>SendEmail</artifactId>    <version>0.0.1-SNAPSHOT</version>    <name>SendEmail</name>    <description>This artiface will send emails using Java Mail API</description> </project>

1. Add following dependencies in your pom.xml file.

<dependencies>     <dependency>             <groupId>com.sun.mail</groupId>             <artifactId>javax.mail</artifactId>             <version>1.6.2</version>         </dependency>   </dependencies>

This will add javax.mail.jar 1.6.2 into your project resources.

Final pom.xml:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">   <modelVersion>4.0.0</modelVersion>   <groupId>SendEmail</groupId>   <artifactId>SendEmail</artifactId>   <version>0.0.1-SNAPSHOT</version>   <name>SendEmail</name>   <description>This artiface will send emails using Java Mail API</description>   <dependencies>     <dependency>             <groupId>com.sun.mail</groupId>             <artifactId>javax.mail</artifactId>             <version>1.6.2</version>         </dependency>   </dependencies> </project>

Step 2 - Create Java Class

1. Right click onProject and create new package and name it com.sendemail

1. Right click on package and create SendMail class
   check to create main method:

In your code, we would require to import the following packages and class.

• import java.util.Properties:
  The Properties class represents a persistent set of properties. The Properties can be saved to a stream or loaded from a stream.
• import javax.mail.Message:
  This class models an email message. To send a message,subclass of Message (e.g. MimeMessage) is instantiated, the attributes and content are filled in, and message is sent using the Transport.send method.
• import javax.mail.MessagingException:
  This is base class for all exceptions thrown by the Messaging classes
• import javax.mail.PasswordAuthentication:
  This class is simply a repository for a user name and a password.
• import javax.mail.Session:
  Session class represents a mail session.
• import javax.mail.Transport:
  This is abstract class that models a message transport.
• import javax.mail.internet.InternetAddress:
  This class represents an Internet email address using the syntax of RFC822
• import javax.mail.internet.MimeMessage:
  This class represents a MIME style email message. It implements the Message abstract class and the MimePart interface.

Sending Email Through Java Using Gmail SMTP

Below is the full Java code to send emails using Gmail SMTP server, with the description of each line:

package com.sendemail;  import java.util.Properties;  import javax.mail.Message; import javax.mail.MessagingException; import javax.mail.PasswordAuthentication; import javax.mail.Session; import javax.mail.Transport; import javax.mail.internet.InternetAddress; import javax.mail.internet.MimeMessage;  public class SendMail {      public static void main(String[] args) {          // Recipient's email ID needs to be mentioned.         String to = "[email protected]";          // Sender's email ID needs to be mentioned         String from = "[email protected]";          // Assuming you are sending email from through gmails smtp         String host = "smtp.gmail.com";          // Get system properties         Properties properties = System.getProperties();          // Setup mail server         properties.put("mail.smtp.host", host);         properties.put("mail.smtp.port", "465");         properties.put("mail.smtp.ssl.enable", "true");         properties.put("mail.smtp.auth", "true");          // Get the Session object.// and pass username and password         Session session = Session.getInstance(properties, new javax.mail.Authenticator() {              protected PasswordAuthentication getPasswordAuthentication() {                  return new PasswordAuthentication("[email protected]", "*******");              }          });          // Used to debug SMTP issues         session.setDebug(true);          try {             // Create a default MimeMessage object.             MimeMessage message = new MimeMessage(session);              // Set From: header field of the header.             message.setFrom(new InternetAddress(from));              // Set To: header field of the header.             message.addRecipient(Message.RecipientType.TO, new InternetAddress(to));              // Set Subject: header field             message.setSubject("This is the Subject Line!");              // Now set the actual message             message.setText("This is actual message");              System.out.println("sending...");             // Send message             Transport.send(message);             System.out.println("Sent message successfully....");         } catch (MessagingException mex) {             mex.printStackTrace();         }      }  }

If you want to send HTML content to replace message.setText("This is actual message") with below code:

          // Send the actual HTML message.        message.setContent(               "<h1>This is actual message embedded in HTML tags</h1>",              "text/html");

Step 3 - Test Java Code

Run Java Application and email will be sent to the recipient. Your console will look like this.

You have successfully sent email using your Java Code.

Now let's send file attachment in your email.

Optional Steps

Step 4 - Send Email with Attachment.

To send a mail with an attachment will have to import a few more classes.

1. import java.io.File and import java.io.IOException
File Class is an abstract representation of file and directory path names and IOException class is a general class of exceptions produced by failed or interrupted I/O operations.

2. import javax.mail.internet.MimeMultipart
This Class is an implementation of the abstract Multipart class that uses MIME conventions for data.

3. import javax.mail.internet.MimeBodyPart
This class represents a MIME body part.
MimeBodyPart uses the InternetHeaders class to parse and store the headers of that body part.

Below is the java code to send an attachment in the email.

The code has two MIME Body part one carrying attachment and other carrying text for email, this is added in Multipart, then this multipart is used to set as the content of the message.

Multipart multipart = new MimeMultipart();              MimeBodyPart attachmentPart = new MimeBodyPart();              MimeBodyPart textPart = new MimeBodyPart();              try {                  File f =new File("H:\\fakepath\\file1.PNG");                  attachmentPart.attachFile(f);                 textPart.setText("This is text");                 multipart.addBodyPart(textPart);                 multipart.addBodyPart(attachmentPart);              } catch (IOException e) {                  e.printStackTrace();              }              message.setContent(multipart);

Here is a running Java Code to send attachments in email:

Java Code To Send Attachment In Email

package com.sendemail;  import java.io.File; import java.io.IOException; import java.util.Properties;  import javax.mail.Message; import javax.mail.MessagingException; import javax.mail.Multipart; import javax.mail.PasswordAuthentication; import javax.mail.Session; import javax.mail.Transport; import javax.mail.internet.InternetAddress; import javax.mail.internet.MimeBodyPart; import javax.mail.internet.MimeMessage; import javax.mail.internet.MimeMultipart;  public class SendMail {      public static void main(String[] args) {          // Recipient's email ID needs to be mentioned.         String to = "[email protected]";          // Sender's email ID needs to be mentioned         String from = "[email protected]";          // Assuming you are sending email from through gmails smtp         String host = "smtp.gmail.com";          // Get system properties         Properties properties = System.getProperties();          // Setup mail server         properties.put("mail.smtp.host", host);         properties.put("mail.smtp.port", "465");         properties.put("mail.smtp.ssl.enable", "true");         properties.put("mail.smtp.auth", "true");          // Get the Session object.// and pass          Session session = Session.getInstance(properties, new javax.mail.Authenticator() {              protected PasswordAuthentication getPasswordAuthentication() {                  return new PasswordAuthentication("[email protected]", "*******");              }          });         //session.setDebug(true);         try {             // Create a default MimeMessage object.             MimeMessage message = new MimeMessage(session);              // Set From: header field of the header.             message.setFrom(new InternetAddress(from));              // Set To: header field of the header.             message.addRecipient(Message.RecipientType.TO, new InternetAddress(to));              // Set Subject: header field             message.setSubject("This is the Subject Line!");              Multipart multipart = new MimeMultipart();              MimeBodyPart attachmentPart = new MimeBodyPart();              MimeBodyPart textPart = new MimeBodyPart();              try {                  File f =new File("H:\\pepipost_tutorials\\javaemail1.PNG");                  attachmentPart.attachFile(f);                 textPart.setText("This is text");                 multipart.addBodyPart(textPart);                 multipart.addBodyPart(attachmentPart);              } catch (IOException e) {                  e.printStackTrace();              }              message.setContent(multipart);              System.out.println("sending...");             // Send message             Transport.send(message);             System.out.println("Sent message successfully....");         } catch (MessagingException mex) {             mex.printStackTrace();         }      }  }

Conclusion

Now you have implemented Java Mail API successfully and can send emails using any SMTP Servers from your project.

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Source: https://netcorecloud.com/tutorials/send-email-in-java-using-gmail-smtp/

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