How to send email asynchronously using spring 4 #Async - java-8

Question

I know this question has been asked but I am not able to send email using configuration. I don't know what I am doing wrong and why I am not getting the email. Here is my Spring configuration.
#Configuration
#PropertySource(value = {
"classpath:autoalert.properties"
})
#EnableAsync
#Import({PersistenceConfig.class, EmailConfig.class, VelocityConfig.class})
#ComponentScan(basePackageClasses = {
ServiceMarker.class,
RepositoryMarker.class }
)
public class AutoAlertAppConfig {
#Bean
public static PropertySourcesPlaceholderConfigurer propertyConfigInDev() {
return new PropertySourcesPlaceholderConfigurer();
}
}
Here is my email config
#Configuration
#PropertySources({
#PropertySource("classpath:email/email.properties")
})
public class EmailConfig {
#Autowired
private Environment env;
#Bean
public JavaMailSender mailSender() {
JavaMailSenderImpl mailSender = new JavaMailSenderImpl();
mailSender.setSession(getEmailSession());
return mailSender;
}
#Bean
public MailMessage mailSettings() {
SimpleMailMessage mailMessage = new SimpleMailMessage();
mailMessage.setFrom(env.getProperty("mail.from"));
...
mailMessage.setText(env.getProperty("mail.body"));
return mailMessage;
}
private Session getEmailSession() {
Properties emailProperties = SpringUtil.loadPropertiesFileFromClassPath("email" + File.separator + "general-mail-settings.properties");
final String userName = emailProperties.getProperty("user");
final String password = emailProperties.getProperty("password");
Session session = null;
try {
session = Session.getInstance(emailProperties, new javax.mail.Authenticator() {
protected PasswordAuthentication getPasswordAuthentication() {
return new PasswordAuthentication(userName, password);
}
}); //end of anonymous class
} catch (Exception e) {
e.printStackTrace();
}
return session;
} //end of getEmailSession()
}
Here is my class
public static void main(String[] args) {
try (GenericApplicationContext springContext = new AnnotationConfigApplicationContext(AutoAlertAppConfig.class)) {
AutoAlertService autoAlertService = springContext.getBean(AutoAlertServiceImpl.class);
try {
autoAlertService.handleProcess(fromDate, toDate);
} catch (Exception e) {
logger.error("Exception occurs", e);
autoAlertService.handleException(fromDate, toDate, e);
}
} catch (Exception e) {
logger.error("Exception occurs in loading Spring context: ", e);
}
#Service
public class AutoAlertServiceImpl implements AutoAlertService {
#Inject
private AsyncEmailService asyncEmailService;
#Override
public void handleProcess(String fromDate, String toDate) {
logger.info("Start process");
try {
..
//Sending email
asyncEmailService.sendMailWithFileAttachment(fromDate, toDate, file);
} catch (Exception e) {
handleException(fromDate, toDate, e);
}
logger.info("Finish process");
}
}
here is my email service
#Component
public class AsyncEmailServiceImpl implements AsyncEmailService {
#Resource(name="mailSender")
private JavaMailSender mailSender;
#Resource(name="mailSettings")
private SimpleMailMessage simpleMailMessage;
#Async
#Override
public void sendMailWithFileAttachment(String from, String to, String attachFile) {
logger.info("Start execution of async. Sending email with file attachment");
MimeMessage message = mailSender.createMimeMessage();
try{
MimeMessageHelper helper = new MimeMessageHelper(message, true);
....
helper.setText(String.format(simpleMailMessage.getText(), from, to));
FileSystemResource file = new FileSystemResource(attachFile);
helper.addAttachment(file.getFilename(), file);
mailSender.send(message);
} catch (MessagingException e) {
logger.error("Exception occurs in sending email with file attachment: " + attachFile, e);
throw new MailParseException(e);
}
logger.info("Complete execution of async. Email with file attachment " + attachFile + " send successfully.");
}
}
When I run the code it comes to method. This is printed on the console
13:59:43.004 [main] INFO com.softech.vu360.autoalert.service.impl.AutoAlertServiceImpl - Finish process
13:59:43.005 [SimpleAsyncTaskExecutor-1] INFO com.softech.vu360.autoalert.service.impl.AsyncEmailServiceImpl - Start execution of async. Sending email with file attachment
13:59:43.007 [main] INFO com.softech.vu360.autoalert.AutoAlert - Exiting application.
But I get no email. In case of Synchronous calling I get the email. Why I am not getting email ? Am I doing something wrong ?
Thanks

Answer 1

I think this is better approach. Create a file AsyncConfig.java
#Configuration
#EnableAsync(proxyTargetClass = true)
#EnableScheduling
public class AsyncConfig implements SchedulingConfigurer, AsyncConfigurer {
private static final Logger log = LogManager.getLogger();
private static final Logger schedulingLogger = LogManager.getLogger(log.getName() + ".[scheduling]");
#Bean
public ThreadPoolTaskScheduler taskScheduler() {
log.info("Setting up thread pool task scheduler with 20 threads.");
ThreadPoolTaskScheduler scheduler = new ThreadPoolTaskScheduler();
scheduler.setPoolSize(2);
scheduler.setThreadNamePrefix("task-");
scheduler.setAwaitTerminationSeconds(1200); // 20 minutes
scheduler.setWaitForTasksToCompleteOnShutdown(true);
scheduler.setErrorHandler(t -> schedulingLogger.error("Unknown error occurred while executing task.", t));
scheduler.setRejectedExecutionHandler((r, e) -> schedulingLogger.error("Execution of task {} was rejected for unknown reasons.", r));
return scheduler;
}
#Override
public Executor getAsyncExecutor() {
Executor executor = this.taskScheduler();
log.info("Configuring asynchronous method executor {}.", executor);
return executor;
}
#Override
public void configureTasks(ScheduledTaskRegistrar registrar) {
TaskScheduler scheduler = this.taskScheduler();
log.info("Configuring scheduled method executor {}.", scheduler);
registrar.setTaskScheduler(scheduler);
}
#Override
public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
return new SimpleAsyncUncaughtExceptionHandler();
}
}
Now import it into your main configuration like this
#Configuration
#PropertySource(value = {
"classpath:autoalert.properties"
})
#Import({AsyncConfig.class, PersistenceConfig.class, EmailConfig.class, VelocityConfig.class})
#ComponentScan(basePackageClasses = {
ServiceMarker.class,
RepositoryMarker.class }
)
public class AutoAlertAppConfig {
#Bean
public static PropertySourcesPlaceholderConfigurer propertyConfigInDev() {
return new PropertySourcesPlaceholderConfigurer();
}
}
Change return type from void to Future
#Service
public class AsyncEmailServiceImpl implements AsyncEmailService {
#Resource(name="mailSender")
private JavaMailSender mailSender;
#Resource(name="mailSettings")
private SimpleMailMessage simpleMailMessage;
#Async
#Override
public Future<String> sendMailWithFileAttachment(String from, String to, String attachFile) {
....
return new AsyncResult<String>("Attachment File successfully send: " + attachFile);
}
#Async
#Override
public Future<String> sendMail(String from, String to, String emailBody) {
....
return new AsyncResult<String>("Email send successfully");
}
}
and in my service class just do this
logger.info("Start process");
try {
....
//Sending email
Future<String> result = asyncEmailService.sendMailWithFileAttachment(fromDate, toDate, file);
} catch (Exception e) {
handleException(fromDate, toDate, e);
}
logger.info("Finish process");
See no need to check result.get(). Now when new Thread starts and application starts to finish. I configured the scheduler.setAwaitTerminationSeconds(1200); // 20 minutes in AsyncConfig.java. This will ensure that all the pending threads must complete before the application shuts down. Ofcourse this can be change according to any ones need.
Now when I run the application it prints these on the console
12:55:33.879 [main] INFO com.softech.vu360.autoalert.service.impl.AutoAlertServiceImpl - Finish process
12:55:33.895 [task-1] INFO com.softech.vu360.autoalert.service.impl.AsyncEmailServiceImpl - Start execution of async. Sending email with file attachment
12:58:09.030 [task-1] INFO com.softech.vu360.autoalert.service.impl.AsyncEmailServiceImpl - Complete execution of async. Email with file attachment D:\projects\AutoAlerts\marketo\autoalert 2015-08-24 to 2015-08-30.csv send successfully.
12:58:09.033 [main] INFO com.softech.vu360.autoalert.AutoAlert - Exiting application.
See starts new thread, but before application shuts down make sure, the thread completes and then exits the application. I configured 20 minutes for email, but as soon as thread completes, application get shut down. This is happy ending :)