Spring Boot配置加载顺序

如果加载的配置有重复的，它们的加载顺序是这样的，数字越小的优先级越高，即优先级高的覆盖优先级低的配置。

1. Devtools global settings properties on your home directory (~/.spring-boot-devtools.properties when devtools is active).
2. @TestPropertySource annotations on your tests.
3. @SpringBootTest#properties annotation attribute on your tests.
4. Command line arguments.
5. Properties from SPRING_APPLICATION_JSON (inline JSON embedded in an environment variable or system property)
6. ServletConfig init parameters.
7. ServletContext init parameters.
8. JNDI attributes from java:comp/env.
9. Java System properties (System.getProperties()).
10. OS environment variables.
11. A RandomValuePropertySource that only has properties in random.*.
12. Profile-specific application properties outside of your packaged jar (application-{profile}.properties and YAML variants)
13. Profile-specific application properties packaged inside your jar (application-{profile}.properties and YAML variants)
14. Application properties outside of your packaged jar (application.properties and YAML variants).
15. Application properties packaged inside your jar (application.properties and YAML variants).
16. @PropertySource annotations on your @Configuration classes.
17. Default properties (specified using SpringApplication.setDefaultProperties).

知道了它们的加载顺序，我们就能知道从哪一步来替换配置。

http://www.javastack.cn/article/2017/spring-boot-config-load-order/