Send emails to multiple email addresses, It feeds email addresses from a csv file - spring-boot

Question

I wanna create an application to send emails to several recipients. It feeds email addresses from a csv file and sends an email to each recipient, and I'm getting some trouble doing this.
Could you help me please?
Here is my CSVHelper.java
#Component
public class CSVHelper
{
public static String TYPE = "text/csv";
static String[] HEADERs = { "id", "email", "dateEcheance"};
//This method is used to filter the csv file and get only the emails
public List<ContactsFile> csvToEmails() throws NumberFormatException, ParseException
{
InputStream is = null;
try (BufferedReader fileReader = new BufferedReader(new InputStreamReader(is, "UTF-8"));
CSVParser csvParser = new CSVParser(fileReader, CSVFormat.DEFAULT.withFirstRecordAsHeader().withIgnoreHeaderCase().withTrim());)
{
List<ContactsFile> emailsList = new ArrayList<>();
Iterable<CSVRecord> csvRecords = csvParser.getRecords();
for (CSVRecord csvRecord : csvRecords)
{
ContactsFile contact = new ContactsFile(csvRecord.get("email"));
emailsList.add(contact);
}
System.out.println(emailsList);
return emailsList;
}
catch (IOException e) { throw new RuntimeException("fail to get emails: " + e.getMessage()); }
}
We call csvToEmails() method in the controller to send the emails
#Autowired
private CSVHelper csvHelper;
#PostMapping("/getdetails")
public #ResponseBody EmailNotification sendMail(#RequestBody EmailNotification details) throws Exception {
MimeMessage message = sender.createMimeMessage();
MimeMessageHelper helper = new MimeMessageHelper(message,
MimeMessageHelper.MULTIPART_MODE_MIXED_RELATED,
StandardCharsets.UTF_8.name());
try {
helper.setTo((InternetAddress) csvHelper.csvToEmails());
helper.setText(details.getMessage(),true);
helper.setSubject("Test Mail");
} catch (javax.mail.MessagingException e) {
e.printStackTrace();
}
sender.send(message);
return details;
this is an example of the csv file:
id,email,dateEcheance
1,address#email.com,10/05/2021
2,address2#email.com,10/02/2021
I'm new to spring boot, and I'm in trouble completing this project.

Answer 1

Assuming that you've mail server configurations in place. First, you need to provide the JavaMailSender implementation. Spring does provide the implementation for the same. You've to create a bean and config the mail server configurations as follows.
#Configuration
public class MailConfig {
#Autowired
private Environment env;
#Bean
public JavaMailSender mailSender() {
try {
JavaMailSenderImpl mailSenderImpl = new JavaMailSenderImpl();
mailSenderImpl.setHost(env.getRequiredProperty("mail.smtp.host"));
mailSenderImpl.setUsername(env.getRequiredProperty("mail.smtp.username"));
mailSenderImpl.setPassword(env.getRequiredProperty("mail.smtp.password"));
mailSenderImpl.setDefaultEncoding(env.getRequiredProperty("mail.smtp.encoding"));
mailSenderImpl.setPort(Integer.parseInt(env.getRequiredProperty("mail.smtp.port")));
mailSenderImpl.setProtocol(env.getRequiredProperty("mail.transport.protocol"));
Properties p = new Properties();
p.setProperty("mail.smtp.starttls.enable", "true");
p.setProperty("mail.smtp.auth", "true");
mailSenderImpl.setJavaMailProperties(p);
return mailSenderImpl;
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}
Configuration settings in application.properties. Add settings according to the mail server.
# SMTP mail settings
mail.smtp.host=**********
mail.smtp.username=**********
mail.smtp.password=**********
mail.smtp.port=**********
mail.smtp.socketFactory.port=**********
mail.smtp.encoding=utf-8
mail.transport.protocol=smtp
mail.smtp.auth=true
mail.smtp.timeout=10000
mail.smtp.starttls.enable=true
mail.smtp.socketFactory.class=javax.net.ssl.SSLSocketFactory
CSVHelper.java
#Component
public class CSVHelper {
// This method is used to filter the csv file and get only the emails
public List<String> csvToEmails() {
InputStream is = ClassLoader.getSystemClassLoader().getResourceAsStream("csvFile.csv");
try (BufferedReader fileReader = new BufferedReader(new InputStreamReader(is, "UTF-8"));
CSVParser csvParser = new CSVParser(fileReader,
CSVFormat.DEFAULT.withFirstRecordAsHeader().withIgnoreHeaderCase().withTrim());) {
List<String> emails = new ArrayList<>();
Iterable<CSVRecord> csvRecords = csvParser.getRecords();
for (CSVRecord csvRecord : csvRecords) {
String email = csvRecord.get("email");
emails.add(email);
}
return emails;
} catch (IOException e) {
throw new RuntimeException("fail to get emails: " + e.getMessage());
}
}
}
Send mail service
#Service
public class MailSenderService {
#Autowired
private CSVHelper csvHelper;
#Autowired
private JavaMailSender sender;
public void sendMail(EmailNotification details) {
try {
List<String> recipients = csvHelper.csvToEmails();
String[] to = recipients.stream().toArray(String[]::new);
JavaMailSenderImpl jms = (JavaMailSenderImpl) sender;
MimeMessage message = jms.createMimeMessage();
MimeMessageHelper helper = new MimeMessageHelper(message, true);
// add the sender email address below
helper.setFrom("sender#mail.com");
helper.setTo(to);
helper.setText(details.getMessage(), true);
helper.setSubject("Test Mail");
sender.send(message);
} catch (javax.mail.MessagingException | NumberFormatException e) {
// action for exception case
}
}
}