Master Spring Boot 3.2.5: Maven Property Expansion & Advanced Config

1. Maven automatic property expansion

Using resource filtering you can expand Maven project properties with @...@ placeholders. Example pack.yml :

<code>pack:
  app:
    java-version: "java.version@"
    springboot-version: "@project.parent.version@"
    sourceEncoding: "@project.build.sourceEncoding@"
</code>

Inject values:

<code>@Value("${pack.app.java-version}")
private String javaVersion;
@Value("${pack.app.springboot-version}")
private String springBootVersion;
@Value("${pack.app.sourceEncoding}")
private String sourceEncoding;
</code>

Result:

<code>java-version: 17.0.9, springboot-version: 3.2.5, sourceEncoding: UTF-8</code>

Maven parent definition:

2. SpringApplication externalized configuration

Set properties under spring.main.* to externalize configuration, e.g.:

<code>spring:
  main:
    web-application-type: servlet
    banner-mode: off
</code>

Other properties can be set programmatically:

<code>SpringApplication app = new SpringApplication(Application.class);
app.setWebApplicationType(WebApplicationType.SERVLET);
app.setBannerMode(Mode.CONSOLE);
app.run(args);
</code>

File‑based configuration overrides code settings.

3. Changing configuration file location and name

Use system properties or environment variables:

spring.config.name (or SPRING_CONFIG_NAME ) – default application

spring.config.location (or SPRING_CONFIG_LOCATION ) – path or URL of the file

Example startup commands:

<code>java -Dspring.config.name=app -jar MyApp.jar
java -Dspring.config.location=d:\xxxooo\app.yml -jar MyApp.jar
</code>

4. Activating profiles

Specify active profiles in application.yml :

<code>spring:
  profiles:
    active:
    - dev
</code>

If no profile is set, the default profile is used; you can change it with:

<code>spring:
  profiles:
    default: dev
</code>

Profile activation image:

5. Setting parent and child containers

<code>SpringApplicationBuilder builder = new SpringApplicationBuilder(Application.class);
builder.child(ChildConfig.class);
builder.parent(ParentConfig.class);
builder.build().run(args);
</code>

6. Customizing DispatcherServlet path

<code>spring:
  mvc:
    servlet:
      path: /api
</code>

Programmatic registration:

<code>@Bean(name = DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME)
public DispatcherServletRegistrationBean dispatcherServletRegistration() {
  DispatcherServlet dispatcherServlet = new DispatcherServlet();
  DispatcherServletRegistrationBean registration = new DispatcherServletRegistrationBean(dispatcherServlet, "/api");
  registration.setName("dispatcherServlet");
  registration.setLoadOnStartup(0);
  return registration;
}
</code>

7. Configuring access logs

<code>server:
  tomcat:
    basedir: "pack-tomcat"
    accesslog:
      enabled: true
      pattern: "%t %a %r %s (%D microseconds)"
</code>

Logs are written under the Tomcat base directory; you can change the directory with the basedir setting.

8. Enabling Tomcat MBean registry

<code>server:
  tomcat:
    mbeanregistry:
      enabled: true
</code>

After enabling, MBean metrics are visible via JConsole.

9. Generating build information

Add the Spring Boot Maven plugin with the build-info goal:

<code><plugin>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-maven-plugin</artifactId>
  <version>3.2.5</version>
  <executions>
    <execution>
      <goals>
        <goal>build-info</goal>
      </goals>
    </execution>
  </executions>
</plugin>
</code>

10. Generating Git information

Include the Git commit ID plugin:

<code><plugin>
  <groupId>io.github.git-commit-id</groupId>
  <artifactId>git-commit-id-maven-plugin</artifactId>
</plugin>
</code>

After building, a git.properties file is packaged in the JAR and can be inspected for repository state.