配置文件加载位置

加载优先级
假定项目路径为project/，
SpringBoot启动会扫描以下位置的application.properties或者application.yml文件作为SpringBoot的默认配置文件

  • /project/config/
  • /project
  • classpath:/config/
  • classpath:/

优先级从高到低，所有配置的文件都会被加载，高优先级配置内容会覆盖低优先级配置内容。

另外我们可以通过配置spring.config.location来改变默认配置，用于项目打包以后，使用命令行参数的形式，启动项目的时候来指定配置文件的新位置；指定配置文件和默认加载的这些配置文件共同起作用，形成互补配置。

spring.config.location测试
在classpath:/config下新建application.yml:

  1. server:
  2.   port: 3333

在K盘下新建application.yml:

  1. server:
  2.   port: 5555
  4. admin:
  5.   name: Khighness

编写controller:

  1. @RestController
  2. public class HelloController {
  4.     @Value("${admin.name}")
  5.     public String adminName;
  7.     @GetMapping("/name")
  8.     public String hello() {
  9.         return adminName;
  10.     }
  12. }

在项目根路径下运行如下命令：

  1. $ mvn apckage
  2. $ cd target
  3. $ java -jar springboot-basic-1.0-SNAPSHOT.jar  --spring.config.location=K:/application.yml

运行结果：

  1. ██╗  ██╗██╗  ██╗██╗ ██████╗ ██╗  ██╗███╗   ██╗███████╗███████╗███████╗
  2. ██║ ██╔╝██║  ██║██║██╔════╝ ██║  ██║████╗  ██║██╔════╝██╔════╝██╔════╝
  3. █████╔╝ ███████║██║██║  ███╗███████║██╔██╗ ██║█████╗  ███████╗███████╗
  4. ██╔═██╗ ██╔══██║██║██║   ██║██╔══██║██║╚██╗██║██╔══╝  ╚════██║╚════██║
  5. ██║  ██╗██║  ██║██║╚██████╔╝██║  ██║██║ ╚████║███████╗███████║███████║
  6. ╚═╝  ╚═╝╚═╝  ╚═╝╚═╝ ╚═════╝ ╚═╝  ╚═╝╚═╝  ╚═══╝╚══════╝╚══════╝╚══════╝
  8. 2021-04-14 22:41:21.494  INFO 1208 --- [           main] top.parak.KhighnessApplication           : Starting KhighnessApplication v1.0-SNAPSHOT on KHighness-Dell with PID 1208 (D:\Java\springboot\springboot-basic\target\springboot-basic-1.0-SNAPSHOT.jar started by 18236 in D:\Java\springboot\springboot-basic\target)
  9. 2021-04-14 22:41:21.497  INFO 1208 --- [           main] top.parak.KhighnessApplication
  10. : No active profile set, falling back to default profiles: default
  11. 2021-04-14 22:41:22.344  INFO 1208 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 5555 (http)
  12. 2021-04-14 22:41:22.354  INFO 1208 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
  13. 2021-04-14 22:41:22.354  INFO 1208 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.29]
  14. 2021-04-14 22:41:22.355  INFO 1208 --- [           main] o.a.catalina.core.AprLifecycleListener   : Loaded APR based Apache Tomcat Native library [1.2.23] using APR version [1.7.0].
  15. 2021-04-14 22:41:22.356  INFO 1208 --- [           main] o.a.catalina.core.AprLifecycleListener   : APR capabilities: IPv6 [true], sendfile [true], accept filters [false], random [true].
  16. 2021-04-14 22:41:22.356  INFO 1208 --- [           main] o.a.catalina.core.AprLifecycleListener   : APR/OpenSSL configuration: useAprConnector [false], useOpenSSL [true]
  17. 2021-04-14 22:41:22.358  INFO 1208 --- [           main] o.a.catalina.core.AprLifecycleListener   : OpenSSL successfully initialized [OpenSSL 1.1.1c  28 May 2019]
  18. 2021-04-14 22:41:22.409  INFO 1208 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
  19. 2021-04-14 22:41:22.409  INFO 1208 --- [           main] o.s.web.context.ContextLoader
  20. 2021-04-14 22:41:22.560  INFO 1208 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
  21. 2021-04-14 22:41:22.634  INFO 1208 --- [           main] o.s.b.a.w.s.WelcomePageHandlerMapping    : Adding welcome page: class path resource [public/index.html]
  22. 2021-04-14 22:41:22.716  INFO 1208 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 5555 (http) with context path ''
  23. 2021-04-14 22:41:22.718  INFO 1208 --- [           main] top.parak.KhighnessApplication           : Started KhighnessApplication in 1.526 seconds (JVM running for 1.819)

接口测试：

  1. $ curl http://localhost:5555/name
  4. StatusCode        : 200
  5. StatusDescription :
  6. Content           : Khighness
  7. RawContent        : HTTP/1.1 200
  8.                     Keep-Alive: timeout=60
  9.                     Connection: keep-alive
  10.                     Content-Length: 9
  11.                     Content-Type: text/plain;charset=UTF-8
  12.                     Date: Wed, 14 Apr 2021 14:46:15 GMT
  14.                     Khighness
  15. Forms             : {}
  16. Headers           : {[Keep-Alive, timeout=60], [Connection, keep-alive], [Content-Length, 9], [Content-Type, text/plain;charset=UTF-8]...}
  17. Images            : {}
  18. InputFields       : {}
  19. Links             : {}
  20. ParsedHtml        : mshtml.HTMLDocumentClass
  21. RawContentLength  : 9

外部配置加载顺序

官方文档
📖 boot-features-external-config

官方文档列举了17种：

  1. Devtools global settings properties on your home directory (~/.spring-boot-devtools.properties when devtools is active).
  2. [@TestPropertySource](https://docs.spring.io/spring/docs/4.3.13.RELEASE/javadoc-api/org/springframework/test/context/TestPropertySource.html) annotations on your tests.
  3. [@SpringBootTest#properties](https://docs.spring.io/spring-boot/docs/1.5.9.RELEASE/api/org/springframework/boot/test/context/SpringBootTest.html) 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](https://docs.spring.io/spring/docs/4.3.13.RELEASE/javadoc-api/org/springframework/context/annotation/PropertySource.html) annotations on your @Configuration classes.
  17. Default properties (specified using SpringApplication.setDefaultProperties).

比较重要
SpringBoot从以下位置加载配置，按照优先级从上至下；
高优先级的配置覆盖低优先级的配置，所有的配置会形成互补配置。
（1）命令行参数（java -jar —=）
（2）来自java:comp/env是JNDI属性
（3）Java系统属性（System.getProperties）
（4）操作系统环境变量
（5）RandomValuePropertySource配置random.*属性值
（6）jar包外部的application-{profilr}.properties或application.yml（带spring.profile）配置文件
（7）jar包内部的application-{profilr}.properties或application.yml（带spring.profile）配置文件
（8）jar包外部的applicatio.properties或application.yml（不带spring.profile）配置文件
（9）jar包内部的applicatio.properties或application.yml（不带spring.profile）配置文件
（10）@Configuration注解类上的@PropertySource

总结
最先加载命令行和环境属性；
优先加载带profile，再加载不带profile，由jar外至jar包内；
最后加载注解。