application.properties

meaningful.prefix.username=whatever
meaningful.prefix.password=ENC(whatever)

MeaningfulClassNameHereProperties.java

@ConfigurationProperties (prefix = "meaningful.prefix")
@Validated
public class MeaningfulClassNameHereProperties {
  /**
   * The username to access meaningfulServiceNameHerePlease.
   */
  @NotBlank
  private String username;
  
  /**
   * The password to access meaningfulServiceNameHerePlease.
   */
  @NotBlank
  private String password;
  
  //Getters and Setters here
}

MyCoolService.java

@Named
public class MyCoolService {
  private final MeaningfulClassNameHereProperties properties;
  
  public MyCoolService(MeaningfulClassNameHereProperties properties) {
    this.properties = properties;
  }
}

pom.xml

...

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-configuration-processor</artifactId>
      <optional>true</optional>
    </dependency>