Applications are typically built once (in JAR or WAR) and then deployed into multiple environments. ;The following figure shows some of the different environments an application can be deployed to:
![](https://static.packt-cdn.com/products/9781787123175/graphics/assets/211bc63c-fe61-4b57-93d9-b9cc0f3afbd8.png)
In each of the preceding environments, an application typically ;has the following:
- Connections to databases
- Connections to multiple ;services
- Specific environment configurations
It is a good practice to externalize configurations that change between different environments into a configuration file or database.
Spring Boot provides ;a flexible, standardized approach for externalized configuration.
In this section, we will look at the following:
- How can properties from ;application.properties be used inside our services?
- How do type-safe Configuration Properties ;make application configuration a cakewalk?
- What kind of support does Spring Boot provide...