JavaMailSender Scheduler

JavaMailSender Scheduler is a Java-based email scheduling application that enables users to schedule emails to be sent at specific times. It utilizes JavaMailSender, a JavaMail API implementation, to send emails through a chosen email service provider.

Features

• Schedule emails to be sent at specific times
• Use multiple email service providers
• Secure email communication using SSL or TLS encryption
• Add attachments and multiple recipients to email messages

Getting started

To get started with JavaMailSender Scheduler, follow these steps:

1. Include the necessary dependencies in your project. You can use Maven or Gradle to add the dependencies to your project.

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-mail</artifactId>
</dependency>

2. Configure JavaMailSender to use your email service provider. You can do this by adding the following properties to your application.properties or application.yml file:

spring.mail.host=your_email_host
spring.mail.port=your_email_port
spring.mail.username=your_email_username
spring.mail.password=your_email_password
spring.mail.properties.mail.smtp.auth=true
spring.mail.properties.mail.smtp.starttls.enable=true

3. Create a Java class to represent your email message. The class should include the subject, body, and recipients of the email message.

public class EmailMessage {
    
    private String subject;
    private String body;
    private List<String> recipients;

    // Getters and setters
}

4. Create a Java class to represent your email scheduler. This class should use JavaMailSender to send the email message at the scheduled time.

@Component
public class EmailScheduler {

    private JavaMailSender javaMailSender;

    @Autowired
    public EmailScheduler(JavaMailSender javaMailSender) {
        this.javaMailSender = javaMailSender;
    }

    // Schedule email message to be sent at a specific time
    public void scheduleEmail(EmailMessage emailMessage, LocalDateTime dateTimeToSend) {
        Runnable task = () -> {
            SimpleMailMessage message = new SimpleMailMessage();
            message.setFrom(emailMessage.getFrom());
            message.setSubject(emailMessage.getSubject());
            message.setText(emailMessage.getBody());
            message.setTo(emailMessage.getRecipients().toArray(new String[0]));
            javaMailSender.send(message);
        };
        ScheduledExecutorService executor = Executors.newScheduledThreadPool(1);
        executor.schedule(task, Duration.between(LocalDateTime.now(), dateTimeToSend).getSeconds(), TimeUnit.SECONDS);
        executor.shutdown();
    }
}

5. Schedule an email message to be sent at a specific time. You can do this by calling the scheduleEmail method on the EmailScheduler class with an instance of your EmailMessage class and the scheduled date and time.

@Autowired
private EmailScheduler emailScheduler;

EmailMessage emailMessage = new EmailMessage();
emailMessage.setSubject("Hello world");
emailMessage.setBody("This is a test email message");

List<String> recipients = new ArrayList<>();
recipients.add("john.doe@example.com");
emailMessage.setRecipients(recipients);

LocalDateTime dateTimeToSend = LocalDateTime.now().plusSeconds(60); // Send email in 60 seconds
emailScheduler.scheduleEmail(emailMessage, dateTimeToSend);

Conclusion

JavaMailSender Scheduler is a powerful tool for scheduling automated email messages. It makes use of the JavaMail API to provide a secure and reliable way to send email messages. By utilizing this tool, developers can automate email communication, streamline workflows, and increase efficiency.