Spring Boot provides the ability to send emails via SMTP using the JavaMail Library. Here we will be illustrating step-by-step guidelines to develop Restful web services that can be used to send emails with or without attachments. In order to begin with the steps, let us first create a Spring Boot project using Spring Initializer.
Implementation:
Step 1: Adding the spring-boot-starter-mail dependency in pom.xml.
XML
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-mail</artifactId></dependency> |
This dependency is a starter for using JavaMail and can be considered as Spring Framework’s email sending support
Step 2: Setting up Application.properties file with configurations required for using Gmail SMTP server.
spring.mail.host=smtp.gmail.com spring.mail.port=587 spring.mail.username=<Login User to SMTP server> spring.mail.password=<Login password to SMTP server> spring.mail.properties.mail.smtp.auth=true spring.mail.properties.mail.smtp.starttls.enable=true
The Gmail Id used to login into your Gmail account can be provided as the username. For password generation, 2-step verification needs to be enabled for your account as follows:
Following that, AppPassword needs to be created using the following path:
Login to Gmail
-> Manage your Google Account
-> Security
-> App Passwords
-> Provide your login password
-> Select app with a custom name
-> Click on Generate
Step 3: Creating EmailDetails class that contains fields such as recipient, msgBody, subject, and attachment.
Java
// Java Program to Illustrate EmailDetails Classpackage com.SpringBootEmail.Entity;// Importing required classesimport lombok.AllArgsConstructor;import lombok.Data;import lombok.NoArgsConstructor;// Annotations@Data@AllArgsConstructor@NoArgsConstructor// Classpublic class EmailDetails { // Class data members private String recipient; private String msgBody; private String subject; private String attachment;} |
Step 4: Creating interface EmailService and implementing class EmailServiceImpl of service layer.
The EmailService interface defines two methods:
- String sendSimpleMail(EmailDetails details): This method can be used to send a simple text email to the desired recipient.
- String sendMailWithAttachment(EmailDetails details): This method can be used to send an email along with an attachment to the desired recipient.
The Interface and service implementation class is as shown below in example as follows:
File: EmailService.java
Java
// Java Program to Illustrate Creation Of// Service Interfacepackage com.SpringBootEmail.service;// Importing required classesimport com.SpringBootEmail.Entity.EmailDetails;// Interfacepublic interface EmailService { // Method // To send a simple email String sendSimpleMail(EmailDetails details); // Method // To send an email with attachment String sendMailWithAttachment(EmailDetails details);} |
JavaMailSender interface of JavaMail API is used here to send simple text email.
To send a more sophisticated email with an attachment, MimeMessage can be used. MimeMessageHelper works as a helper class for MimeMessage to add the attachment and other details required to send the mail.
File: EmailServiceImpl.java
Java
// Java Program to Illustrate Creation Of// Service implementation classpackage com.SpringBootEmail.service;// Importing required classesimport com.SpringBootEmail.Entity.EmailDetails;import java.io.File;import javax.mail.MessagingException;import javax.mail.internet.MimeMessage;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.beans.factory.annotation.Value;import org.springframework.core.io.FileSystemResource;import org.springframework.mail.SimpleMailMessage;import org.springframework.mail.javamail.JavaMailSender;import org.springframework.mail.javamail.MimeMessageHelper;import org.springframework.stereotype.Service;// Annotation@Service// Class// Implementing EmailService interfacepublic class EmailServiceImpl implements EmailService { @Autowired private JavaMailSender javaMailSender; @Value("${spring.mail.username}") private String sender; // Method 1 // To send a simple email public String sendSimpleMail(EmailDetails details) { // Try block to check for exceptions try { // Creating a simple mail message SimpleMailMessage mailMessage = new SimpleMailMessage(); // Setting up necessary details mailMessage.setFrom(sender); mailMessage.setTo(details.getRecipient()); mailMessage.setText(details.getMsgBody()); mailMessage.setSubject(details.getSubject()); // Sending the mail javaMailSender.send(mailMessage); return "Mail Sent Successfully..."; } // Catch block to handle the exceptions catch (Exception e) { return "Error while Sending Mail"; } } // Method 2 // To send an email with attachment public String sendMailWithAttachment(EmailDetails details) { // Creating a mime message MimeMessage mimeMessage = javaMailSender.createMimeMessage(); MimeMessageHelper mimeMessageHelper; try { // Setting multipart as true for attachments to // be send mimeMessageHelper = new MimeMessageHelper(mimeMessage, true); mimeMessageHelper.setFrom(sender); mimeMessageHelper.setTo(details.getRecipient()); mimeMessageHelper.setText(details.getMsgBody()); mimeMessageHelper.setSubject( details.getSubject()); // Adding the attachment FileSystemResource file = new FileSystemResource( new File(details.getAttachment())); mimeMessageHelper.addAttachment( file.getFilename(), file); // Sending the mail javaMailSender.send(mimeMessage); return "Mail sent Successfully"; } // Catch block to handle MessagingException catch (MessagingException e) { // Display message when exception occurred return "Error while sending mail!!!"; } }} |
Step 5: Creating a Rest Controller EmailController which defines various API for sending email.
Java
// Java Program to Create Rest Controller that// Defines various API for Sending Mailpackage com.SpringBootEmail.controller;// Importing required classesimport com.SpringBootEmail.Entity.EmailDetails;import com.SpringBootEmail.service.EmailService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.PostMapping;import org.springframework.web.bind.annotation.RequestBody;import org.springframework.web.bind.annotation.RestController;// Annotation@RestController// Classpublic class EmailController { @Autowired private EmailService emailService; // Sending a simple Email @PostMapping("/sendMail") public String sendMail(@RequestBody EmailDetails details) { String status = emailService.sendSimpleMail(details); return status; } // Sending email with attachment @PostMapping("/sendMailWithAttachment") public String sendMailWithAttachment( @RequestBody EmailDetails details) { String status = emailService.sendMailWithAttachment(details); return status; }} |
Step 6: Running the Spring Boot Application and hitting http://localhost:8080/sendMail to send a simple email
Mail received on Gmail is as follows:
Step 7: Running the Spring Boot Application and hitting http://localhost:8080/sendMailWithAttachment to send an email along with an attachment.
Mail received on Gmail is as follows:
