Spring Boot - @Value annotation doesn't work
13,581
You guessed it right, the values will get injected only after the objects gets instantiated; because the spring container cannot set a property of something which doesn't exist yet. So while in constructer, those fields will still be null. One solution is, either
- Switch to constructer Injection instead of setter Injection (YMMV, havnt tested your usecase)
Or
- Replace the constructor with a method annotated with
@PostConstruct
. This method will be executed after the injection process.
for example
@Component
public class SmtpAuthenticator extends Authenticator {
private static final Logger LOG =
LogManager.getLogger(SmtpAuthenticator.class.getSimpleName());
@Value("${spring.mail.username}")
private String username;
@Value("${spring.mail.password}")
private String password;
@PostConstruct
public void init() {
LOG.info(SmtpAuthenticator.class.getSimpleName() + " started...");
LOG.debug("username=" + username);
}
@Override
protected PasswordAuthentication getPasswordAuthentication() {
if (!StringUtils.isEmpty(username) && !StringUtils.isEmpty(password)) {
LOG.debug("Username and password are correct...");
return new PasswordAuthentication(username, password);
}
LOG.error("Not correct mail login data!");
return null;
}
}
Author by
Sir Montes
I am Java frontend/backend developer, partly with PHP and Perl knowledge.
Updated on June 17, 2022Comments
-
Sir Montes almost 2 years
I try to create mail service using SmtpAuthenticator. The component is started correctly but null values are in username and password fields. Why is it?
@Component public class SmtpAuthenticator extends Authenticator { private static final Logger LOG = LogManager.getLogger(SmtpAuthenticator.class.getSimpleName()); @Value("${spring.mail.username}") private String username; @Value("${spring.mail.password}") private String password; public SmtpAuthenticator() { LOG.info(SmtpAuthenticator.class.getSimpleName() + " started..."); LOG.debug("username=" + username); } @Override protected PasswordAuthentication getPasswordAuthentication() { if (!StringUtils.isEmpty(username) && !StringUtils.isEmpty(password)) { LOG.debug("Username and password are correct..."); return new PasswordAuthentication(username, password); } LOG.error("Not correct mail login data!"); return null; } }