How to send mails in Spring Boot Applications

The Spring Framework provides a straightforward abstraction for sending email by using the JavaMailSender interface, and Spring Boot provides auto-configuration for it as well as a starter module. Start by creating a new project which uses the “mail” starter module:

spring init -dmail demo-mail

The following dependencies will be added:

<?xml version="1.0" encoding="UTF-8"?><project>
   <dependencies>
       	
      <dependency>
          		
         <groupId>org.springframework.boot</groupId>
          		
         <artifactId>spring-boot-starter-mail</artifactId>
          	
      </dependency>
       	
      <dependency>
          		
         <groupId>org.springframework.boot</groupId>
          		
         <artifactId>spring-boot-starter-test</artifactId>
          		
         <scope>test</scope>
          	
      </dependency>
       
   </dependencies>
</project>

Next, add a class that uses the JavaMailSender interface to send mail messages:

package com.example.demomail;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.mail.MailException;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.mail.javamail.MimeMessagePreparator;
import org.springframework.stereotype.Service;
@Service public class MailClient {
  private JavaMailSender mailSender;
  @Autowired public MailClient(JavaMailSender mailSender) {
    this.mailSender = mailSender;
  }
  public void prepareAndSend(String recipient, String message) {
    MimeMessagePreparator messagePreparator = mimeMessage -> {
      MimeMessageHelper messageHelper = new MimeMessageHelper(mimeMessage);messageHelper.setFrom("john.doeATgmail.com");messageHelper.setTo(recipient);messageHelper.setSubject("Sample mail subject");messageHelper.setText(message);
    };
    try {
      mailSender.send(messagePreparator);
    } catch (MailException e) {
      // runtime exception; compiler will not force you to handle it
    }
  }
}

Finally, you can include the SMTP configuration into the application.properties file:

spring.mail.host=localhost spring.mail.port=25 spring.mail.username= spring.mail.password=   spring.mail.protocol=smtp

Mail properties can also be defined programmatically using the JavaMailSenderImpl. For example:

@Bean public JavaMailSender getJavaMailSender() {
  JavaMailSenderImpl mailSender = new JavaMailSenderImpl();
  mailSender.setHost("smtp.gmail.com");
  mailSender.setPort(587);
  mailSender.setUsername("john.doeATgmail.com");
  mailSender.setPassword("12345678");
  Properties props = mailSender.getJavaMailProperties();
  props.put("mail.transport.protocol", "smtp");
  props.put("mail.smtp.auth", "true");
  props.put("mail.smtp.starttls.enable", "true");
  props.put("mail.debug", "true");
  return mailSender;
}