Spring Boot is not an entirely new framework, in fact, it’s an extension of the Spring framework. Spring Boot includes all of the same modules that Spring does.
- Features of Spring Boot
- Example: Features of Spring Boot
- Spring Boot Project Structure
- Maven File (pom.xml)
- Application Config (application.properties, application-dev.properties, application-qa.properties)
- Spring Boot Main: @SpringBootApplication
- Set dev profile: mvn spring-boot:run
- Set qa profile: mvn spring-boot:run
- Override profile @runtime : mvn spring-boot:run -Dspring.profiles.active=qa
- Download Source Code (Attached)
Features of Spring Boot
Spring Boot does this by automatically pre-configuring virtually all of the third party libraries that you will use.
Spring Boot also makes use of the Parent pom.xml. Instead of explicitly specifying all the dependencies and versions that you need within your pom.xml, in your Maven build configuration, you’ll simply use a parent pom which has most of the dependencies pre-configured with the right versions as well.
The starter dependency templates are an important part of Spring Boot.
The auto-configuration feature in Spring Boot relies on specific Spring annotations, which are variants of the @Configuration annotation. Each @Configuration annotation is an opinionated default specified by your app. Now, these @Configuration annotations are used conditionally, which means that if you have overridden the default specification for some property, your overridden version will be used, not the default. Thus, Spring Boot respects user-provided defaults. So if you don’t want the default specification, you can override it. Otherwise, the default specification is there for you to use. Spring Boot auto-configuration automatically detects and adds beans that you haven’t explicitly manually configured. Within a Spring Boot app, you need to opt-in to this auto-configuration by adding to the entry point of your app.
@EnableAutoConfiguration or @SpringBootApplicationAnd finally, Spring Boot also simplifies Spring by allowing you to use the Spring Initializr. The Spring Initializr is basically just a web interface that you can use to set up your initial project structure for Spring Boot.
Instead of manually setting up your Spring Boot project, you can use the Spring Initializr and download a zip file with your project. And all of the dependencies that you’ve specified set up for you automatically.
Spring Boot Profiles – How to Set an Active profile?
Once you have profile specific configuration, you would need to set the active profile in an environment.
Using -Dspring.profiles.active=qa in VM Arguments
Use spring.profiles.active=qa in application.propertiesLets set it in application.properties by add another property to application.propertiesspring.profiles.active=qa
Example: Features of Spring Boot
In this example, we will see how we can set an active profile through properties file or runtime.
Spring Boot Project Structure
High-level project structure would be like this.
Maven File (pom.xml)
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>spring-boot-active-profile</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>spring-boot-active-profile</name>
<description>Microservice for setting an active profile in Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.4.4</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>Application Config (application.properties, application-dev.properties, application-qa.properties)
application.properties
spring.profiles.active=devapplication-dev.properties
file.directory=some_path_here
cmdb.resource-url=http://www.dev.com
cmdb.resourcePort[0]=80
cmdb.resourcePort[1]=443application-qa.properties
file.directory=some_path_here
cmdb.resource-url=http://www.qa.com
cmdb.resourcePort[0]=8080
cmdb.resourcePort[1]=543Spring Boot Main: @SpringBootApplication
package com.the.basic.tech.info.active.profile.app;
import java.util.List;
import javax.annotation.PostConstruct;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Configuration;
/*
mvn spring-boot:run -Dspring.profiles.active=qa
NOTE: Give above command from command line
replace qa with dev
*/
@Configuration
@ConfigurationProperties("cmdb")
class CmdbProperties {
private String resourceUrl;
private List<Integer> resourcePort;
@Override
public String toString() {
return "resourceUrl: " + this.resourceUrl + "\n" + "resourcePort: " + this.resourcePort + "\n";
}
public String getResourceUrl() {
return resourceUrl;
}
public void setResourceUrl(String resourceUrl) {
this.resourceUrl = resourceUrl;
}
public List<Integer> getResourcePort() {
return resourcePort;
}
public void setResourcePort(List<Integer> resourcePort) {
this.resourcePort = resourcePort;
}
}
@SpringBootApplication
public class SpringBootActiveProfileExample {
@PostConstruct
public void print() {
System.out.println("Properties from properties file:" + cmdbProperties.toString());
}
@Autowired
private CmdbProperties cmdbProperties;
public static void main(String[] args) {
ApplicationContext ctx = SpringApplication.run(SpringBootActiveProfileExample.class, args);
}
}Set dev profile: mvn spring-boot:run
spring.profiles.active=devApplication logs
2021-05-29 17:41:18.230 INFO 11412 --- [ main] t.i.a.p.a.SpringBootActiveProfileExample : The following profiles are active: dev
2021-05-29 17:41:19.750 INFO 11412 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2021-05-29 17:41:19.750 INFO 11412 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2021-05-29 17:41:19.750 INFO 11412 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.44]
2021-05-29 17:41:19.850 INFO 11412 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2021-05-29 17:41:19.850 INFO 11412 --- [ main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 1551 ms
Properties from properties file:resourceUrl: http://www.dev.com
resourcePort: [80, 443]
2021-05-29 17:41:20.019 INFO 11412 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor'
2021-05-29 17:41:20.166 INFO 11412 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2021-05-29 17:41:20.182 INFO 11412 --- [ main] t.i.a.p.a.SpringBootActiveProfileExample : Started SpringBootActiveProfileExample in 2.5 seconds (JVM running for 3.106)Set qa profile: mvn spring-boot:run
spring.profiles.active=qa2021-05-29 17:43:50.651 INFO 3212 --- [ main] t.i.a.p.a.SpringBootActiveProfileExample : The following profiles are active: qa
2021-05-29 17:43:52.811 INFO 3212 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2021-05-29 17:43:52.831 INFO 3212 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2021-05-29 17:43:52.831 INFO 3212 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.44]
2021-05-29 17:43:52.927 INFO 3212 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2021-05-29 17:43:52.927 INFO 3212 --- [ main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 2213 ms
Properties from properties file:resourceUrl: http://www.qa.com
resourcePort: [8080, 543]
2021-05-29 17:43:53.112 INFO 3212 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor'
2021-05-29 17:43:53.281 INFO 3212 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2021-05-29 17:43:53.297 INFO 3212 --- [ main] t.i.a.p.a.SpringBootActiveProfileExample : Started SpringBootActiveProfileExample in 3.178 seconds (JVM running for 3.697)Override profile @runtime : mvn spring-boot:run -Dspring.profiles.active=qa
mvn spring-boot:run -Dspring.profiles.active=qa2021-05-29 17:49:53.519 INFO 9416 --- [ main] t.i.a.p.a.SpringBootActiveProfileExample : The following profiles are active: qa
2021-05-29 17:49:55.277 INFO 9416 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2021-05-29 17:49:55.293 INFO 9416 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2021-05-29 17:49:55.293 INFO 9416 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.44]
2021-05-29 17:49:55.393 INFO 9416 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2021-05-29 17:49:55.393 INFO 9416 --- [ main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 1789 ms
Properties from properties file:resourceUrl: http://www.qa.com
resourcePort: [8080, 543]
2021-05-29 17:49:55.594 INFO 9416 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor'
2021-05-29 17:49:55.741 INFO 9416 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2021-05-29 17:49:55.748 INFO 9416 --- [ main] t.i.a.p.a.SpringBootActiveProfileExample : Started SpringBootActiveProfileExample in 2.89 seconds (JVM running for 3.397)
