Spring Boot send email
last modified July 28, 2023
In this article we show how to send email in a Spring Boot application. We use a Mailtrap service.
Spring is a popular Java application framework and Spring Boot is an evolution of Spring which helps create stand-alone, production-grade Spring based applications easily.
Spring Boot email example
In the following example, we create an application that sends an email to Mailtrap account. We need to register an account if we do not have one. The registration process is very easy and fast. There is a free tier for sending 500 emails per month.
Note: Gmail is not ideal for testing applications. We should use an online service such as Mailtrap or Mailgun, or use an SMTP server provided by a webhosting company.
The application has a web interface to send the email. In addition, email can be send from a test.
build.gradle
...
src
├───main
│ ├───java
│ │ └───com
│ │ └───zetcode
│ │ │ Application.java
│ │ ├───controller
│ │ │ MyController.java
│ │ └───service
│ │ EmailService.java
│ └───resources
│ │ application.properties
│ ├───static
│ │ index.html
│ └───templates
│ emailsent.ftlh
└───test
└───java
└───com
└───zetcode
SendEmailApplicationTest.java
This is the project structure of the Spring Boot application.
plugins {
id 'org.springframework.boot' version '3.1.1'
id 'io.spring.dependency-management' version '1.1.0'
id 'java'
}
group = 'com.zetcode'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '17'
repositories {
mavenCentral()
}
dependencies {
implementation 'org.springframework.boot:spring-boot-starter-web'
implementation 'org.springframework.boot:spring-boot-starter-freemarker'
implementation 'org.springframework.boot:spring-boot-starter-mail'
testImplementation 'org.springframework.boot:spring-boot-starter-test'
}
test {
useJUnitPlatform()
}
We have project dependencies in build.gradle. For emails, we need
to declare spring-boot-starter-mail.
spring.main.banner-mode=off spring.mail.protocol=smtp spring.mail.host=sandbox.smtp.mailtrap.io spring.mail.port=2525 spring.mail.username=-mailtrapusername- spring.mail.password=-mailtrappasswd- spring.mail.properties.mail.smtp.auth = true spring.mail.properties.mail.smtp.starttls.enable = true
We configure the email settings for Mailtrap. These details are provided in our Mailtrap account.
package com.zetcode.controller;
import com.zetcode.service.EmailService;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
@Controller
public class MyController {
private final EmailService emailService;
public MyController(EmailService emailService) {
this.emailService = emailService;
}
@GetMapping(value = "/sendmail")
public String sendmail() {
emailService.sendMail("kate@example.com", "Test Subject", "Test mail");
return "emailsent";
}
}
The controller contains a mapping that sends an email.
package com.zetcode.service;
import org.springframework.mail.SimpleMailMessage;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.stereotype.Service;
@Service
public class EmailService {
private JavaMailSender javaMailSender;
public EmailService(JavaMailSender javaMailSender) {
this.javaMailSender = javaMailSender;
}
public void sendMail(String toEmail, String subject, String message) {
var mailMessage = new SimpleMailMessage();
mailMessage.setTo(toEmail);
mailMessage.setSubject(subject);
mailMessage.setText(message);
mailMessage.setFrom("johndoe@example.com");
javaMailSender.send(mailMessage);
}
}
The email service sends a simple email using JavaMailSender and
SimpleMailMessage.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Home page</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
</head>
<body>
<a href="sendmail">Send mail</a>
</body>
</html>
The index.html file is the home page. It contains an anchor to send
the email.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Email sent</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
</head>
<body>
<p>
Email was sent
</p>
</body>
</html>
The template contains a simple message that is displayed after successful email dispatch.
package com.zetcode;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
Application is the entry point which sets up Spring Boot
application.
package com.zetcode;
import com.zetcode.service.EmailService;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
@SpringBootTest
public class SendEmailApplicationTest {
@Autowired
private EmailService emailService;
@Test
public void testEmail() {
emailService.sendMail("frank23@example.com", "Test subject", "Test mail");
}
}
This is a test for sending email.
$ ./gradlew bootRun
After the application is run, we can navigate to localhost:8080.
In this article we have shown how to send an email in Spring Boot.