Maybe any spring-user already solved this? How do you handle it?

Hey guys, does anybody have a hint for me on how to return from the following .onSuccess?

@GetMapping("/{id}")
    fun getEmployeeById(@PathVariable id: Long): ResponseEntity<EntityModel<Employee>> {
        runCatching { getUseCase.getEmployee(id) }
                .onFailure { throw ResourceNotFoundException("User with id $id not found.") }
                .onSuccess {
                    val entityModel = EntityModel(it, linkTo<EmployeeController> { getEmployeeById(id) }.withSelfRel())
                    return ResponseEntity(entityModel, HttpStatus.OK)
                }
    }

getUseCase.getEmployee(id)

can throw an exception that I want to map to an ResourceNotFoundException. I tried to do it in idiomatic Kotlin, but I got stuck at that point. I guess there is another way of achieving this that didn't come up to my mind yet. When there's no exception, the entityModel should be created and returned in an ResponseEntity.

As a noob who started learning Kotlin about a month ago (with almost no experience with Java, just skimmed through the Oracle’s Java 8 documentation before jumping into Kotlin) and just started with Spring framework, I want to ask for advice about how I should learn further. I followed the tutorial https://spring.io/guides/tutorials/spring-boot-kotlin/, but of course this just was merely getting a taste of it. Can anyone give some advice how I should further learn about the Spring framework efficiently? Some questions that I had in mind: 1. Is it better to go through Spring Framework’s documentation before going through Spring Boot’s documentation? 2. Is it better to start with simpler frameworks, such as Spring MVC, before jumping into Spring WebFlux?

A short question: Which annotation of Spring is handling the conversion between the Kotlin data class object and JSON? Or is this done by some other external library? I made a minimal example with Spring Boot + Kotlin, following this post https://grokonez.com/spring-framework/spring-boot/kotlin-springboot-jquery-ajax-postget. I wanted to learn about AJAX together with Spring Boot. I just changed the jQuery code into vanilla Javascript by myself. I chose in Spring Initializr: • Template Engine -> Thymeleaf (I’m not sure if this was really needed) • Web -> Web (MVC)

@RestController
class RestWebController {

    val custStore = mutableListOf<Customer>()

    @GetMapping("/getallcustomer")
    fun getAllCustomer(): Response {
        println("GET: getallcustomer $custStore")
        return Response("Done", custStore)
    }

    @PostMapping("/postcustomer")
    fun postCustomer(@RequestBody customer: Customer): Response {
        println("POST: postcustomer $customer")
        custStore.add(customer)
        return Response("Done", customer)
    }
}

data class Response(
    val status: String = "",
    val data : Any
)

data class Customer(
    val firstname: String = "",
    val lastname: String = ""
)

message has been deleted

I'm struggling with providing instances of Beans for SpringBoot tests, can anyone see what I'm doing wrong please:

@SpringBootApplication
class DemoApplication

fun main(args: Array<String>) {
    runApplication<DemoApplication>(*args)
}

@Component
class NormalComponent() {
    fun value() = "Hi"
}

Test:

@TestConfiguration
class TestConfig {

	@Bean
	fun normalComponentMock(): NormalComponent {
		val mock =  mock(NormalComponent::class.java)
		`when`(mock.value()).thenReturn("I AM A MOCK!")
		return mock
	}
}

@SpringBootTest
@Import(TestConfig::class)
class DemoApplicationTests(
	@Autowired val norm: NormalComponent
) {
	@Test
	fun normInjectedIntoTest() {
		assertEquals("I AM A MOCK!", norm.value())
	}
}

The error:

org.junit.jupiter.api.extension.ParameterResolutionException: Failed to resolve parameter [com.example.demo.NormalComponent norm] in constructor [public com.example.demo.DemoApplicationTests(com.example.demo.NormalComponent)]: No qualifying bean of type 'com.example.demo.NormalComponent' available: expected single matching bean but found 2: normalComponent,normalComponentMock

I know I could use

@MockBean

- this is just a simple example where the bean I want to inject to the instance. Bit confused why the mock conflict is happening when I have using the

@TestConfiguration

and the

@Import

annotation - thanks in advance 🙏

I'm having some issues with using hibernate with Kotlin. I have configured the no-args plugin with JPA https://kotlinlang.org/docs/reference/compiler-plugins.html#jpa-support , but still I get this error

No default constructor for entity

. Is there anything else I need to to concider?

Hey guys, since I couldn't find anything on the web I thought I might ask you guys: I get the same error in every single spring project I create:

<build>
        <sourceDirectory>${project.basedir}/src/main/kotlin</sourceDirectory>
        <testSourceDirectory>${project.basedir}/src/test/kotlin</testSourceDirectory>

Cannot resolve directory '$'{'project.basedir}'

I guess it's something with my configuration but I just can't point the finger at it. Any ideas? Thanks ahead!

next week, i’ll have an online free talk Migrating Spring Boot Config Annotations to Functional Kotlin https://www.meetup.com/Tech-Meetups-ING/events/269742393/

How can I access resources in src/main/resources from test?

hello! what is the preferred way to structure various configuration files, e.g. given some common configuration beans is it better to

@Configuration @Import([A, B])
class TopLevelConfig {
  // uses beans from A/B
  // defines beans used commonly by A and B
}

or

@Configuration
class CommonConfig { // common beans }

@Configuration @Import(CommonConfig)
class A

@Configuration @Import(CommonConfig)
class B

@Configuration @Import([A, B])
class TopLevelConfig { // use beans from A/B }

Hey Folks, we are running a little Webflux service in our team. We use

kotlinx.coroutins.reactor

package to bridge both worlds (reactive -> Coroutines). Now we want to build an custom

ReactiveHealthIndicator

. Therefore we inherit this interface

ReactiveHealthIndicator

from

package org.springframework.boot.actuate.health

which expects to implement an method with the signature of

fun health(): Mono<Health>

. So far, so good. The problem is that we need to call an suspending function Inside the

health()

method. Here is a little snippet, which should explain the problem a bit further:

@Component
class ClientHealthIndicator(private val client: SomeClient) : ReactiveHealthIndicator {
    private val logger = KotlinLogging.logger { }
    override fun health(): Mono<Health> =
        try {
            client.getPage("home") // THIS IS THE SUSPEND FUNCTION
            Health.up().build().let { Mono.just(it) }
        } catch (e: Exception) {
            logger.error(e) { "ContentClient health check failed" }
            Health.down(e).build().let { Mono.just(it) }
        }
}

We tried to use the MonoCoroutine Builder function from

kotlinx.coroutins.reactor

to build an scope which returns a Mono.

@Component
class ContentClientHealthIndicator(private val contentJsonClient: ContentJsonClient) : ReactiveHealthIndicator {
    private val logger = KotlinLogging.logger { }
    override fun health(): Mono<Health> = mono {
        try {
            contentJsonClient.getPage(it)
            Health.up().build()
        } catch (e: Exception) {
            logger.error(e) { "ContentClient health check failed" }
            Health.down(e).build()
        }
    }
}

This does look good, but fails as fullfiling solution because the only thing that get´s catched is this:

kotlinx.coroutines.JobCancellationException: MonoCoroutine was cancelled

I am a bit helpless here and would appreciate any help. Thanks in advance Dennis

I need to send temporary file content with webflux and coroutines, but I want do delete the file after that. Where can I run

zipFile.delete()

? Currently I have this:

suspend fun download(request: ServerRequest): ServerResponse {
	val zipFile = // get the temporary <http://java.io|java.io>.File from a different service
	ServerResponse.ok().contentLength(zipFile.length())
	.contentType(MediaType.parseMediaType("application/zip"))
        .header("Content-Disposition", "attachment; filename=\"file.zip\"")
        .bodyValueAndAwait(FileSystemResource(zipFile))
}

Is there any callback I can use? I don't want to read the file into temporary

ByteArray

.

hello! I’m hitting some weird problem with a custom

BeanPostProcessor

that my application context fails to load up as it fails to resolve some of the post processor dependencies complaining about unability to parse out

SPeL

value passed for one its parameters. My understanding is that Spring post processors should be applied at that point as they are

PriorityOrdered

so they take precedence over the regular ordered beans. Using Spring Boot 2.2.5.RELEASE It’s a longshot but just wondering if anyone here hit some similar issue.

Hey guys. I have a problem with such `RestControllerAdvice`:

@RestControllerAdvice
class ExceptionHandlingAdvice {

    @ExceptionHandler(NotImplementedError::class)
    fun notImplementedYet(exception: NotImplementedError): ResponseEntity<ErrorResponse> =
        exception.toNotImplementedErrorResponse()

    @ExceptionHandler(Throwable::class)
    fun unexpectedException(exception: Throwable): ResponseEntity<ErrorResponse> =
        exception.toInternalServerErrorResponse()
}

When I call

TODO()

method somewhere in the application the

kotlin.NotImplementedError

is occurred. However, the first hadler does not get it. Does anybody has such a problem?

Are there any guides on how to configure multiple datasources with Kotlin and Spring? I'm trying to follow Java-guide, but I'm having issues with the naming strategy of the Entities. It translates "TableName" to "tablename" instead of "table_name".

I'm trying to use

testCoroutineScope

in a

@SpringBootTest

. Having trouble. To get started, do you know any examples or docs for this?

I am using io.github.microutils:kotlin-logging:1.7.6 for logging. I am looking for ways to scrub , hide sensitive data in logs.

Hi guys, I am trying to offer kotlin as a language for next project in my company. I am preparing some presentation about the features of the language. I want to show the real numbers as well something like how many projects from spring initializr have chosen kotlin as a language. Who knows when can I get such information?

how to get the body of ServerRequest (in suspend style no bodyToMono) of a dataclass ?

awaitBody()

https://docs.spring.io/spring-framework/docs/5.2.6.RELEASE/kdoc-api/spring-framework/org.springframework.web.reactive.function.server/index.html

is it possible to instantiate 2 beans of the same data class eg.

@Configuration
class DataSourceConfig {

    companion object {
        private val logger = LoggerFactory.getLogger(DataSourceConfig::class.java)
    }

    @ConstructorBinding
    @ConfigurationProperties(prefix = "datasource.default")
    data class DefaultDataSource(
        val host: String,
        val port: Int,
        val database: String,
        val username: String,
        val password: String
    ) {
        init {
            <http://logger.info|logger.info>(toString())
        }
    }

    @ConstructorBinding
    @ConfigurationProperties(prefix = "datasource.write")
    data class WriteDataSource(
        val host: String,
        val port: Int,
        val database: String,
        val username: String,
        val password: String
    ) {
        init {
            <http://logger.info|logger.info>(toString())
        }
    }

    @Bean
    fun defaultFactory(defaultDataSource: DefaultDataSource): ConnectionFactory {
        return ConnectionFactories.get(
            ConnectionFactoryOptions.builder()
                .option(ConnectionFactoryOptions.DRIVER, "pool")
                .option(ConnectionFactoryOptions.PROTOCOL, "postgresql")
                .option(ConnectionFactoryOptions.HOST, defaultDataSource.host)
                .option(ConnectionFactoryOptions.PORT, defaultDataSource.port)
                .option(ConnectionFactoryOptions.USER, defaultDataSource.username)
                .option(ConnectionFactoryOptions.PASSWORD, defaultDataSource.password)
                .option(ConnectionFactoryOptions.DATABASE, defaultDataSource.database)
                .build()
        )
    }

    @Bean
    fun writeFactory(writeDataSource: WriteDataSource): ConnectionFactory {
        return ConnectionFactories.get(
            ConnectionFactoryOptions.builder()
                .option(ConnectionFactoryOptions.DRIVER, "pool")
                .option(
                    ConnectionFactoryOptions.PROTOCOL,
                    "postgresql"
                )
                .option(ConnectionFactoryOptions.HOST, writeDataSource.host)
                .option(ConnectionFactoryOptions.PORT, writeDataSource.port)
                .option(ConnectionFactoryOptions.USER, writeDataSource.username)
                .option(ConnectionFactoryOptions.PASSWORD, writeDataSource.password)
                .option(ConnectionFactoryOptions.DATABASE, writeDataSource.database)
                .build()
        )
    }


    @Bean
    @Primary
    fun databaseClient(@Qualifier("defaultFactory") connectionFactory: ConnectionFactory) =
        DatabaseClient.create(connectionFactory)


    @Bean
    fun writeDatabaseClient(@Qualifier("writeFactory") connectionFactory: ConnectionFactory) =
        DatabaseClient.create(connectionFactory)

}

Can I clean this up into something that scales when I need to coneect to multiple dbs

Nicely done... Love the slices idea 🙂

Hi everyone any idea how to create a json object with json array in your controller? As the example attached

@sandjelkovic Thank you for your comment : Can your example code be runnable like a daemon in background ?

Hi a newbie here learning Kotlin and Spring, and I have some questions regarding writing

@Entity

class: 1. Should one NOT use

data class

for defining

@Entity

class? I’ve found some articles which say that one shouldn’t, but then I’ve also seen many sources just using them. 2. When defining the properties for an

@Entity

class, is there a rule to be followed for either using

val

or

var

? 3. For

@Id

@GeneratedValue

property, what is the better way to define it: either as a nullable property initialized with

null

? or as a non-nullable property initialized with other dummy value?

Not with Gradle GraalVM integration but good point I should update the Kotlin sample to use Gradle KTS. Could you create an issue for that ? I will take care.

but the thing is in most cases you can use the jvm while in development and only use native-image once in a while to check it works

hello everyone, i’m a newbie to use kotlin to develop web/backend applications and i didn’t know how to start also, should I be familiar with spring to write web/backend applications using kotin?