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. @ConfigurationProperties annotation allows to access properties set in configuration files (application.properties or application.yml) automatically and powerfully.
YAML and Properties
- application.yml
logging:
level:
org.springframework: ERROR
com.example: DEBUG
spring:
profiles:
active: dev
main:
banner-mode: off
email: haunt.hcm2015@gmail.com
thread-pool: 10
wordpress:
menus:
- title: Home
name: Home
path: /
- title: About
name: About
path: /about
themes:
default-folder: /wp-content/themes/toptech
servers:
- ip: 127.0.0.1
path: /dev1
- ip: 127.0.0.2
path: /dev2
- ip: 127.0.0.3
path: /dev3
- application.properties ```properties
Spring Boot
logging.level.org.springframework=ERROR
logging.level.com.mkyong=DEBUG
spring.profiles.active=dev
spring.main.banner-mode=off
Global
email=haunt.hcm2015@gmail.com
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/toptech
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
## Project Structure
![](https://i.imgur.com/Z6dlkHR.png)
## Project Dependency
Spring Boot uses **_SnakeYAML_** library to parse the YAML file, and the **_SnakeYAML_** library is provided by **_spring-boot-starter_**
The library and dependencies are configured in the **_pom.xml_** file
```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>
<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>
Spring Boot + YAML
Spring Boot will load and parse the YAML file and bind the values in the following @ConfigurationProperties classes.
- Menu.java
package com.example.yaml.config.model;
public class Menu {
private String name;
private String path;
private String title;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPath() {
return path;
}
public void setPath(String path) {
this.path = path;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
@Override
public String toString() {
return "Menu{" +
"name='" + name + '\'' +
", path='" + path + '\'' +
", title='" + title + '\'' +
'}';
}
}
- Server.java
package com.example.yaml.config.model;
public class Server {
private String ip;
private String path;
public String getIp() {
return ip;
}
public void setIp(String ip) {
this.ip = ip;
}
public String getPath() {
return path;
}
public void setPath(String path) {
this.path = path;
}
@Override
public String toString() {
return "Server{" +
"ip='" + ip + '\'' +
", path='" + path + '\'' +
'}';
}
}
- Theme.java
package com.example.yaml.config.model;
public class Theme {
private String defaultFolder;
public String getDefaultFolder() {
return defaultFolder;
}
public void setDefaultFolder(String defaultFolder) {
this.defaultFolder = defaultFolder;
}
@Override
public String toString() {
return "Theme{" +
"defaultFolder='" + defaultFolder + '\'' +
'}';
}
}
- GlobalProperties.java
package com.example.yaml.config;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
@Component
@ConfigurationProperties
public class GlobalProperties {
private int threadPool;
private String email;
public int getThreadPool() {
return threadPool;
}
public void setThreadPool(int threadPool) {
this.threadPool = threadPool;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
@Override
public String toString() {
return "GlobalProperties{" +
"threadPool=" + threadPool +
", email='" + email + '\'' +
'}';
}
}
The setter (and getter) names must correspond to the property names in the application.properties (or application.yml)
- WordPressProperties.java
package com.example.yaml.config;
import com.example.yaml.config.model.Menu;
import com.example.yaml.config.model.Server;
import com.example.yaml.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<>();
public List<Menu> getMenus() {
return menus;
}
public void setMenus(List<Menu> menus) {
this.menus = menus;
}
public Theme getThemes() {
return themes;
}
public void setThemes(Theme themes) {
this.themes = themes;
}
public List<Server> getServers() {
return servers;
}
public void setServers(List<Server> servers) {
this.servers = servers;
}
@Override
public String toString() {
return "WordpressProperties{" +
"menus=" + menus +
", themes=" + themes +
", servers=" + servers +
'}';
}
}
Spring will automatically look for properties placed inside application.properties or application.yml prefixed with wordpress and inject them into the corresponding properties in the WordPressProperties class.
Start a Spring Boot normally and print out the values.
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