We will start with creating a service returning a hardcoded string. After that, we will discuss an example returning a proper JSON response. We will also look at an example of passing a path parameter.
Let's start with creating a simple REST service returning a welcome message:
@RestController
class BasicController {
@GetMapping("/welcome")
fun welcome() = "Hello World"
}A comparable Java method is shown as follows. A major difference is how we are able to define a function in one line in Kotlin--fun welcome() = "Hello World":
@GetMapping("/welcome")
public String welcome() {
return "Hello World";
}If we run FirstWebServiceWithKotlinApplication.kt as a Kotlin application, it will start up the embedded Tomcat container. We can launch up the URL (http://localhost:8080/welcome) in the browser, as shown in the following screenshot:
