Spring Mail – Sending Email with Thymeleaf HTML Template Example

by MemoryNotFound · Published October 5, 2017 · Updated March 1, 2018

In this tutorial we demonstrate how to send a HTML email using a custom thymeleaf template using spring framework. In this topic we learn how to create and configure a custom thymeleaf template using spring.

Project Structure

Let’s start by looking at our project structure.

Maven Dependencies

We use Apache Maven to manage our project dependencies. Make sure the following dependencies reside on your class-path.

<?xml version="1.0" encoding="UTF-8"?>
<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>com.memorynotfound.mail</groupId>
    <artifactId>mail-template-thymeleaf</artifactId>
    <version>1.0.0-SNAPSHOT</version>
    <url>https://memorynotfound.com</url>
    <name>Spring MAIL - ${project.artifactId}</name>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.7.RELEASE</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-mail</artifactId>
        </dependency>
        <dependency>
            <groupId>org.thymeleaf</groupId>
            <artifactId>thymeleaf-spring4</artifactId>
        </dependency>
        <dependency>
            <groupId>nz.net.ultraq.thymeleaf</groupId>
            <artifactId>thymeleaf-layout-dialect</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.5.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

Email Configuration Properties

We can use two types of configuration files. Both files reside on the classpath located in the src/main/resources folder. The first and my favorite is application.yml file. I like this type because it has a better structure than the other and you’ll have to type less.

# application.yml

spring:
  mail:
    default-encoding: UTF-8
    host: smtp.gmail.com
    username: [email protected]
    password: secret
    port: 587
    properties:
      mail:
        smtp:
          auth: true
          starttls:
            enable: true
    protocol: smtp
    test-connection: false

The second option you can use is the application.properties file.

# application.properties

spring.mail.default-encoding=UTF-8
spring.mail.host=smtp.gmail.com
[email protected]
spring.mail.password=secret
spring.mail.port=587
spring.mail.protocol=smtp
spring.mail.test-connection=false
spring.mail.properties.mail.smtp.auth=true
spring.mail.properties.mail.smtp.starttls.enable=true

Mail Object

We are using this Mail object to pass as an argument for our EmailService to encapsulate the details of an email message and content.

package com.memorynotfound.mail;

public class Mail {

    private String from;
    private String to;
    private String subject;
    private String content;

    public Mail() {
    }

    public Mail(String from, String to, String subject, String content) {
        this.from = from;
        this.to = to;
        this.subject = subject;
        this.content = content;
    }

    public String getFrom() {
        return from;
    }

    public void setFrom(String from) {
        this.from = from;
    }

    public String getTo() {
        return to;
    }

    public void setTo(String to) {
        this.to = to;
    }

    public String getSubject() {
        return subject;
    }

    public void setSubject(String subject) {
        this.subject = subject;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

    @Override
    public String toString() {
        return "Mail{" +
                "from='" + from + '\'' +
                ", to='" + to + '\'' +
                ", subject='" + subject + '\'' +
                ", content='" + content + '\'' +
                '}';
    }
}

Thymeleaf Template Java Configuration

We need to tell Thymeleaf where the email templates are located. We do this by creating and configuring the SpringResourceTemplateResolver. We can set a prefix and suffix to configure where Thymeleaf will search for the HTML email templates. Next, we need to create a SpringTemplateEngine which is responsible for resolving the correct templating engine.

package com.memorynotfound.mail;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.thymeleaf.spring4.SpringTemplateEngine;
import org.thymeleaf.spring4.templateresolver.SpringResourceTemplateResolver;
import org.thymeleaf.templatemode.StandardTemplateModeHandlers;
import java.nio.charset.StandardCharsets;

@Configuration
public class ThymeleafConfig {

    @Bean
    public SpringTemplateEngine springTemplateEngine() {
        SpringTemplateEngine templateEngine = new SpringTemplateEngine();
        templateEngine.addTemplateResolver(htmlTemplateResolver());
        return templateEngine;
    }

    @Bean
    public SpringResourceTemplateResolver htmlTemplateResolver(){
        SpringResourceTemplateResolver emailTemplateResolver = new SpringResourceTemplateResolver();
        emailTemplateResolver.setPrefix("classpath:/templates/");
        emailTemplateResolver.setSuffix(".html");
        emailTemplateResolver.setTemplateMode(StandardTemplateModeHandlers.HTML5.getTemplateModeName());
        emailTemplateResolver.setCharacterEncoding(StandardCharsets.UTF_8.name());
        return emailTemplateResolver;
    }
}

Thymeleaf HTML Email Template

Now it’s time to write the actual Thymeleaf HTML email template. This file is located in the src/main/resources/templates folder. We create a very basic HTML email template. Notice, we are linking to an email attachment by using the cid: inside the src attribute inside the <img/> element. This image will be attached as an attachment in the email service.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title>Sending Email with Thymeleaf HTML Template Example</title>

    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0"/>

    <link href='http://fonts.googleapis.com/css?family=Roboto' rel='stylesheet' type='text/css'>

    <!-- use the font -->
    <style>
        body {
            font-family: 'Roboto', sans-serif;
            font-size: 48px;
        }
    </style>
</head>
<body style="margin: 0; padding: 0;">

    <table align="center" border="0" cellpadding="0" cellspacing="0" width="600" style="border-collapse: collapse;">
        <tr>
            <td align="center" bgcolor="#78ab46" style="padding: 40px 0 30px 0;">
                <img src="cid:logo.png" alt="https://memorynotfound.com" style="display: block;" />
            </td>
        </tr>
        <tr>
            <td bgcolor="#eaeaea" style="padding: 40px 30px 40px 30px;">
                <p>Dear ${name},</p>
                <p>Sending Email using Spring Boot with <b>Thymeleaf template !!!</b></p>
                <p>Thanks</p>
            </td>
        </tr>
        <tr>
            <td bgcolor="#777777" style="padding: 30px 30px 30px 30px;">
                <p>${signature}</p>
                <p>${location}</p>
            </td>
        </tr>
    </table>

</body>
</html>

Populating HTML Email with Thymeleaf Template

First, we can create a MimeMessage using the JavaMailSender.createMimeMessage() method. Next, we create a MimeMessageHelper and pass in the MimeMessage as an argument. The MimeMessageHelper let’s us add attachments to the MimeMessage.

Next, we process the HTML Thymeleaf Email Template by calling the SpringTemplateEngine.process() method and passing a Context object, which holds all the key value pairs we can use inside the template.

package com.memorynotfound.mail;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.stereotype.Service;
import org.thymeleaf.context.Context;
import org.thymeleaf.spring4.SpringTemplateEngine;

import javax.mail.MessagingException;
import javax.mail.internet.MimeMessage;
import java.io.IOException;
import java.nio.charset.StandardCharsets;

@Service
public class EmailService {

    @Autowired
    private JavaMailSender emailSender;

    @Autowired
    private SpringTemplateEngine templateEngine;


    public void sendSimpleMessage(Mail mail) throws MessagingException, IOException {
        MimeMessage message = emailSender.createMimeMessage();
        MimeMessageHelper helper = new MimeMessageHelper(message,
                MimeMessageHelper.MULTIPART_MODE_MIXED_RELATED,
                StandardCharsets.UTF_8.name());

        helper.addAttachment("logo.png", new ClassPathResource("memorynotfound-logo.png"));

        Context context = new Context();
        context.setVariables(mail.getModel());
        String html = templateEngine.process("email-template", context);

        helper.setTo(mail.getTo());
        helper.setText(html, true);
        helper.setSubject(mail.getSubject());
        helper.setFrom(mail.getFrom());

        emailSender.send(message);
    }

}

Spring Mail – Sending Email with Thymeleaf HTML Template Example

We are using Spring Boot to bootstrap our application. When the application is invoked we simply create a new Mail object and send it using our previously created EmailService

package com.memorynotfound.mail;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import java.util.HashMap;
import java.util.Map;

@SpringBootApplication
public class Application implements ApplicationRunner {

    private static Logger log = LoggerFactory.getLogger(Application.class);

    @Autowired
    private EmailService emailService;

    public static void main(String[] args) throws Exception {
        SpringApplication.run(Application.class, args);
    }

    @Override
    public void run(ApplicationArguments applicationArguments) throws Exception {
        log.info("Sending Email with Thymeleaf HTML Template Example");

        Mail mail = new Mail();
        mail.setFrom("[email protected]");
        mail.setTo("[email protected]");
        mail.setSubject("Sending Email with Thymeleaf HTML Template Example");

        Map model = new HashMap();
        model.put("name", "Memorynotfound.com");
        model.put("location", "Belgium");
        model.put("signature", "https://memorynotfound.com");
        mail.setModel(model);

        emailService.sendSimpleMessage(mail);
    }
}