Spring Boot @ConfigurationProperties example 2016-03-01 07:52

In Spring you can use @PropertySource and @Value to load value from properties file. You can also use them in Spring Boot. But Spring Boot provide a easy way to get value from properties file. In this page I will show you how to use @ConfigurationProperties to get the value in properties file.

Require

• Maven3
• Intellij

Project Structure

Create a maven project in Intellij, make structure as following.

├─main
│  ├─java
│  │  └─com
│  │      └─henry
│  │          └─properties
│  │                  DefaultProperties.java
│  │                  SimpleController.java
│  │                  SpecialProperties.java
│  │
│  └─resources
│          application.properties
│          server.properties
│
└─test
    └─java

Dependencies in pom.xml file

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    <version>1.3.2.RELEASE</version>
</dependency>

Properties files

In this tutorial I will show you loading properties from two properties files. application.properties is default properties file in Spring Boot. If you do not want save any properties in application.properties you can create another one like server.properties. I recommend you create another properties to save your own properties.

content of application.properties

server.info.address=192.168.1.1
server.info.username=user1
server.info.password=password

content of server.properties

server.info.address=192.168.1.2
server.info.username=user2
server.info.password=password2

Java code

In order to load properties in class we create DefaultProperties class. Make the properties in DefaultProperties and application.properties match.

@Configuration
@ConfigurationProperties(prefix = "server.info")
public class DefaultProperties {
    private String address;
    private String username;
    private String password;

    //getter and setter methods

    @Override
    public String toString() {
        return "DefaultProperties{" +
                "address='" + address + '\'' +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

@ConfigurationProperties annotation tell Spring Boot this class is bound to properties file. Use prefix define special prefix to match properties in configuration file. If you want get properties from special file instead of application.properties. You can create SpecialProperties as following.

@Configuration
@ConfigurationProperties(locations="classpath:server.properties",prefix = "server.info")
public class SpecialProperties {
    private String address;
    private String username;
    private String password;

    //getter and setter methods

    @Override
    public String toString() {
        return "SpecialProperties{" +
                "address='" + address + '\'' +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

The only difference is add locations property in @ConfigurationProperties.

In order to start this project we need a controller.

@RestController
@EnableAutoConfiguration
@ComponentScan(value = "com.henry.xi.properties")
public class SimpleController {
    @Autowired
    private DefaultProperties defaultProperties;

    @Autowired
    private SpecialProperties specialProperties;

    @RequestMapping(value = "/properties", method = RequestMethod.GET)
    public String getProperties() {
        return defaultProperties.toString() + "<br>" + specialProperties.toString();
    }

    public static void main(String[] args) {
        SpringApplication.run(SimpleController.class, args);
    }
}

Run main method in SimpleController and access http://localhost:8080/properties you will see the result as following.

DefaultProperties{address='192.168.1.1', username='user1', password='password'}
SpecialProperties{address='192.168.1.2', username='user2', password='password2'}

That's all, happy learning.