Spring Boot YAML example
In this article, we will show you how to use YAML instead of properties file in Spring Boot.
Tested with :
- Spring Boot 2.1.2.RELEASE
- Maven 3
- Snakeyaml:jar:1.23
In short, create a application.yml
in the src/resources
folder, Spring Boot will load and parse .yml
file automatically and bind the values into the classes which annotated with @ConfigurationProperties
P.S YAML files cannot be loaded by using the `@PropertySource`
1. YAML and Properties
logging:
level:
org.springframework: ERROR
com.mkyong: DEBUG
spring:
profiles:
active: dev
main:
banner-mode: off
email: [email protected]
thread-pool: 10
wordpress:
menus:
- title: Home
name: Home
path: /
- title: About
name: About
path: /about
themes:
default-folder: /wp-content/themes/mkyong
servers:
- ip: 127.0.0.1
path: /dev1
- ip: 127.0.0.2
path: /dev2
- ip: 127.0.0.3
path: /dev3
# Spring Boot
logging.level.org.springframework=ERROR
logging.level.com.mkyong=DEBUG
spring.profiles.active=dev
spring.main.banner-mode=off
# Global
[email protected]
thread-pool=10
# WordPress
wordpress.menus[0].title=Home
wordpress.menus[0].name=Home
wordpress.menus[0].path=/
wordpress.menus[1].title=About
wordpress.menus[1].name=About
wordpress.menus[1].path=/about
wordpress.themes.default-folder=/wp-content/themes/mkyong
wordpress.servers[0].ip=127.0.0.1
wordpress.servers[0].path=/dev1
wordpress.servers[1].ip=127.0.0.2
wordpress.servers[1].path=/dev2
wordpress.servers[2].ip=127.0.0.3
wordpress.servers[2].path=/dev3
2. Project Structure
3. Project Dependency
Spring Boot uses SnakeYAML library to parse the YAML file, and the SnakeYAML library is provided by spring-boot-starter
<?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>
<artifactId>spring-boot-yaml-example</artifactId>
<packaging>jar</packaging>
<name>Spring Boot YAML Example</name>
<url>https://www.mkyong.com</url>
<version>1.0</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.2.RELEASE</version>
</parent>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.0</version>
</plugin>
</plugins>
</build>
</project>
Project Dependencies :
+- org.springframework.boot:spring-boot-starter:jar:2.1.2.RELEASE:compile
[INFO] | +- org.springframework.boot:spring-boot:jar:2.1.2.RELEASE:compile
[INFO] | | \- org.springframework:spring-context:jar:5.1.4.RELEASE:compile
[INFO] | | +- org.springframework:spring-aop:jar:5.1.4.RELEASE:compile
[INFO] | | +- org.springframework:spring-beans:jar:5.1.4.RELEASE:compile
[INFO] | | \- org.springframework:spring-expression:jar:5.1.4.RELEASE:compile
[INFO] | +- org.springframework.boot:spring-boot-autoconfigure:jar:2.1.2.RELEASE:compile
[INFO] | +- org.springframework.boot:spring-boot-starter-logging:jar:2.1.2.RELEASE:compile
[INFO] | | +- ch.qos.logback:logback-classic:jar:1.2.3:compile
[INFO] | | | \- ch.qos.logback:logback-core:jar:1.2.3:compile
[INFO] | | +- org.apache.logging.log4j:log4j-to-slf4j:jar:2.11.1:compile
[INFO] | | | \- org.apache.logging.log4j:log4j-api:jar:2.11.1:compile
[INFO] | | \- org.slf4j:jul-to-slf4j:jar:1.7.25:compile
[INFO] | +- javax.annotation:javax.annotation-api:jar:1.3.2:compile
[INFO] | +- org.springframework:spring-core:jar:5.1.4.RELEASE:compile
[INFO] | | \- org.springframework:spring-jcl:jar:5.1.4.RELEASE:compile
[INFO] | \- org.yaml:snakeyaml:jar:1.23:runtime <<------------- SnakeYAML
4. Spring Boot + YAML
4.1 Spring Boot will load and parse the YAML file and bind the values in the following @ConfigurationProperties
classes.
package com.mkyong.config;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
@Component
@ConfigurationProperties // no prefix, root level.
public class GlobalProperties {
//thread-pool , relax binding
private int threadPool;
private String email;
//... getters and setters, toString()
}
package com.mkyong.config;
import com.mkyong.config.model.Menu;
import com.mkyong.config.model.Server;
import com.mkyong.config.model.Theme;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
import java.util.ArrayList;
import java.util.List;
@Component
@ConfigurationProperties("wordpress")
public class WordPressProperties {
private List<Menu> menus = new ArrayList<>();
private Theme themes;
private List<Server> servers = new ArrayList<>();
//... getters and setters, toString()
}
4.2 Model, nothing special, just some standard classes.
package com.mkyong.config.model;
public class Menu {
private String name;
private String path;
private String title;
//... getters and setters, toString()
}
package com.mkyong.config.model;
public class Server {
private String ip;
private String path;
//... getters and setters, toString()
}
package com.mkyong.config.model;
public class Theme {
private String defaultFolder;
//... getters and setters, toString()
}
4.3 Start a Spring Boot normally and print out the values.
package com.mkyong;
import com.mkyong.config.GlobalProperties;
import com.mkyong.config.WordpressProperties;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class Application implements CommandLineRunner {
@Autowired
private WordPressProperties wpProperties;
@Autowired
private GlobalProperties globalProperties;
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
@Override
public void run(String... args) {
System.out.println(globalProperties);
System.out.println(wpProperties);
}
}
5. DEMO
Package and run it.
# run spring boot directly
$ mvn spring-boot:run
# or package and run it
$ mvn package
$ java -jar target/spring-boot-yaml-example-1.0.jar
Output
GlobalProperties{
threadPool=10,
email='[email protected]'
}
WordpressProperties{
menus=[
Menu{name='Home', path='/', title='Home'},
Menu{name='About', path='/about', title='About'}
],
themes=Theme{defaultFolder='/wp-content/themes/mkyong'},
servers=[
Server{ip='127.0.0.1', path='/dev1'},
Server{ip='127.0.0.2', path='/dev2'},
Server{ip='127.0.0.3', path='/dev3'}
]
}
Refer to this Spring Boot + Multiple Profiles YAML example
Hi, nice article!. One query: how to process when you want to split the configuration on different ymls and just have the master that includes the others (this to avoid huge yml files)
For instance:
master-profesion.yml
————–
profesions:
– !include profesion-xxx.yml
– !include profesion-yyy.yml
————–
profesion-xxx.yml
————–
profesion:
name: XXXX
salary: AAAA
————–
profesion-yyy.yml
————–
profesion:
name: YYYYY
salary: BBBB
————–
Could you please create a example of this implementation?.
Regards,
Make sure it should be in application.yml:
main:
banner-mode: ‘off’
NOT
main:
banner-mode: off
So that is the way to read in properties from a yaml property file in Spring! Works like a charm. I have been struggling with this the entire morning and afternoon! Mkyong comes through were Baeldung and others don’t. No need for a special YAML property source factory or any such Spring plumbing.
Doesn’t work but found the answer you need to change quote banner-mode: off to banner-mode: “off” otherwise it thinks it’s a boolean. https://github.com/spring-projects/spring-boot/issues/13045. Other than that it works fine.
Do I must sepcify the active profile in the application.yaml? Can not I pass it to the mvn command like mvn install -Pdev?