Using Maven properties in application.properties in Spring Boot

Question

I'm trying to load properties from pom.xml into application.properties. I want to create two profiles: dev and prod to use different database urls. I'm using Jenkins as CI, in all my apps (Spring MVC mainly, without Boot project) are using maven profiles to deploy to Tomcat. There is any posibility to do this using maven properties? I tried something like that: spring.datasource.url=${jdbc.url}

Answer 1

Before you do it, consider externalizing the properties file out of your deployable package. This way you can deploy the same compilation on every environment. It will save your Jenkins some work that is actually unnecessary. The best practice is to build your application only once, however, if you are not convinced, here is how to do it.

1. In your pom.xml define the profiles with appropriate values for the property.

   <profile>
       <id>dev</id>
      <properties>
          <jdbc.url>your_dev_URL</jdbc.url>
      </properties>
   </profile>
   

2. Setup the Maven Resources Plugin to filter the directory which contains your application.properties file.

   <build>
       <resources>
           <resource>
               <directory>src/main/resources</directory>
               <filtering>true</filtering>
           </resource>
       </resources>
       ...
   </build>
   

3. If you use Spring Boot 1.3 or more, you should be aware of the fact that to avoid conflicts between Spring Boot placeholders and tokens filtered by the Maven Resources Plugin, the framework introduced a solution that requires using a different syntax for filtered values.

   Now, instead ${property.key} you should use @property.key@. In this case, your application.properties must contain the following sample to work as you expect:

   spring.datasource.url=@jdbc.url@
   

You can also check out a post about separating Spring properties files for different Maven profiles. That way you will externalize the values from your pom.xml.

Answer 2

Of course there is. Just use Maven Filtering over your application.properties file and Maven will write your profile specific values in the file.

However, you must understand that while Maven profiles work at application package/build time, Spring Boot ones do at runtime. In other words, with Maven profiles you'll get profile specific immutable builds, while when using the ones from Spring Boot you'll be able to change your application configuration every time before launching it or even while it's running.

See also:

• Externalize the configuration of SpringApplication