Best way define important credentials in spring boot

Many techniques

• Using tokens replacement (maven replacor)

  application.properties spring.datasource.password=#MY_DB_PASSWORD#
  tokens.properties #MY_DB_PASSWORD#=SECRET_PASSWORD

  where tokens.properties has an access protection

• Using environment variable
  mvn spring-boot:run -Dspring.datasource.password=SECRET_PASSWORD

  or simply
  spring.datasource.password=${myDbPasswordEnv}

• Using Jaspyt to encrypt your properties

One solution is to use Environment variables and property placeholders in the application properties. Lets say, you want to store the password of the database. Create an environment variable:

setx DEV_DB_PASS <your_dev_database_password>

Now, in the application properties file, you can access this value as:

spring.datasource.password = ${DEV_DB_PASS}

You can refer to the official documentation.