Environment variables in application.yml doesn't work with default values that start with a space

Question

I have following application.yml:

sftp:
  sessionFactory:
    host: ${HOST:127.0.0.1}
    username: ${USERNAME:test}
    password: ${PASSWORD: test}

The password starts with a space. When starting the Spring Boot application it is crashing with:

    Caused by: mapping values are not allowed here
 in 'reader', line 26, column 25:
        password: ${PASSWORD: test}

When trying with ${PASSWORD:' test'}, the value of the password is password=' test' instead of password= test.

Before introducing the environment variables the application.yml looked like this:

sftp:
  sessionFactory:
    host: 127.0.0.1
    username: test
    password: ' test'

and everything worked properly.

Any idea how such a default value that starts with space can be specified? Thanks.

Answer 1

Edit: I want to clarify that SpEL only works for @Value bound properties as documented here. @ConfigurationProperties does not support SpEL expressions.

SpEL lets you combine raw strings and operaters. In your case you just want a plain string so you can define your property like so:

password: ${PASSWORD:#{' test'}}

##Example code

application.yaml

testing:
  my:
    username: ${USERNAME:user}
    password: ${PASSWORD:#{' test'}}

Testing.java

@Component
public class Testing {

  @Value("${testing.my.username}")
  String username;

  @Value("${testing.my.password}")
  String password;

  @PostConstruct
  public void post() {
    System.out.println("User: (" + username + ")");
    System.out.println("Pass: (" + password + ")");
  }

log

User: (user)
Pass: ( test)