How can I use properties from a configuration (properties/yml) file in my Spring Boot application?

Question

how can I use external configurations within my Spring application?

package hello.example2.Container

import org.springframework.web.bind.annotation.PathVariable
import org.springframework.web.bind.annotation.RequestMapping
import org.springframework.web.bind.annotation.RestController
import org.springframework.web.client.RestTemplate

@RestController
class ContainerController {
    @RequestMapping("/container/{cid}")
    public list(@PathVariable Integer cid) {
        def template = new RestTemplate();
        def container = template.getForObject("http://localhost:5050/container/" + cid.toString(), Container);
        return container;
    }
}

I want to replace "http://localhost:5050" with a configuration option (f.e. application.yml or application.properties).

This is my application file (Groovy):

package hello.example2

import groovy.transform.CompileStatic
import org.springframework.boot.SpringApplication
import org.springframework.boot.autoconfigure.EnableAutoConfiguration
import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.context.annotation.Configuration

@SpringBootApplication
@Configuration
@EnableAutoConfiguration
@CompileStatic
class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

I tried to set "@Configuration" and "@EnableAutoConfiguration" but to be honest I don't know what they are doing. I'm new to Java/Groovy and the Spring framework (but not to programming in general).

I have read these pages but there is no complete example only snippets:

[1] http://docs.spring.io/spring-boot/docs/current/reference/html/howto-properties-and-configuration.html

[2] https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-external-config.html

Answer 1

In your configuration file (application.yml or application.properties) add a new entry:

endpointUrl: http://localhost:5050

Then inject that property in your controller:

@RestController
class ContainerController {

    @Value("${endpointUrl}")
    private String ednpointUrl;

    @RequestMapping("/container/{cid}")
    public list(@PathVariable Integer cid) {
        def template = new RestTemplate();
        def container = template.getForObject(endpointUrl+"/container/" + cid.toString(), Container);
        return container;
    }
}