SpringBoot Kotlin Controllers

Controllers help define API endpoints that an application exposes. You can use one of the below ways to define controllers in SpringBoot.

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@Controller §

package starter.main.content
 
import org.springframework.web.bind.annotation.GetMapping
import org.springframework.web.bind.annotation.RestController
 
@Controller
class StarterController {
 
    @GetMapping("/")
    fun sayHello(): String {
        return "hello.html"
    }
}

Warning hello.html should be located within Resources/static

Should return a ModelAndView object or a String view name

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@RestController §

package starter.main.content
 
import org.springframework.web.bind.annotation.GetMapping
import org.springframework.web.bind.annotation.RestController
 
@RestController
class StarterController {
 
    @GetMapping("/")
    fun sayHello(): String {
        return "Hello"
    }
}

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@Controller (RESTful) §

package starter.main.content
 
import org.springframework.web.bind.annotation.GetMapping
import org.springframework.web.bind.annotation.RestController
 
@Controller
class StarterController {
 
    @GetMapping("/")
    @ResponseBody
    fun sayHello(): String {
        return "Hello"
    }
}

@ResponseBody is mandatory for @Controller in a REST api endpoint as we typically return data directly

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Related §

• SpringBoot Whitelabel Error Page