Spring Boot #Autowired custom application.properties - spring

Question

i am trying to get my custon application.properties fields working within a kotlin spring boot application.
My Current Setup:
ApplicationProperties.kt:
#Configuration
#ConfigurationProperties("mt")
class ApplicationProperties {
var initDatabase: Boolean? = null
val kafka = Kafka()
class Kafka {
lateinit var host: String
lateinit var port: String
}
}
application.properties:
mt.kafka.host=localhost
mt.kafka.port=9092
mt.init-database=true
And a class where i want to use my application:
InitApp.kt
#Component
#EnableTransactionManagement
#EnableConfigurationProperties(ApplicationProperties::class)
class InitApp {
#Autowired
lateinit var conf: ApplicationProperties
#Bean
fun createKafkaConsumer() {
log.info("${conf.kafka.host}")
}
}
Sadly this doesn't work because i get a:
Caused by: kotlin.UninitializedPropertyAccessException: lateinit property conf has not been initialized
I followed this "guide" Bootiful Kotlin by Sébastien Deleuze and Josh Long # Spring I/O 2018 and i am using these versions:
kotlinVersion = '1.2.51'
springBootVersion = '2.0.5.RELEASE'
apply plugin: 'kotlin-kapt' is in my build.gradle, but this should not mess with the #Autowired since, as far as i understood, it is for autocompletion in my application.properties.
Update 1:
I had a look at: Building web applications with Spring Boot and Kotlin and added the #EnableConfigurationProperties at Application level. This didn't work either
Update 2:
Full stacktrace:
2018-10-10 16:17:53.058 ERROR 23619 --- [ restartedMain] o.s.boot.SpringApplication : Application run failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'producerFactory' defined in class path resource [de/mikatiming/de/test/InitApp.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.kafka.core.ProducerFactory]: Factory method 'producerFactory' threw exception; nested exception is kotlin.UninitializedPropertyAccessException: lateinit property applicationProperties has not been initialized
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:590) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1247) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1096) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:535) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:495) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:759) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:869) ~[spring-context-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:780) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:412) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:333) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1277) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1265) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at de.mikatiming.de.test.TestApplicationKt.main(TestApplication.kt:15) [main/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_172]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_172]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_172]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_172]
at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-2.0.5.RELEASE.jar:2.0.5.RELEASE]
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.kafka.core.ProducerFactory]: Factory method 'producerFactory' threw exception; nested exception is kotlin.UninitializedPropertyAccessException: lateinit property applicationProperties has not been initialized
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:582) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
... 23 common frames omitted
Caused by: kotlin.UninitializedPropertyAccessException: lateinit property applicationProperties has not been initialized
at de.mikatiming.de.test.InitApp.getApplicationProperties(InitApp.kt:36) ~[main/:na]
at de.mikatiming.de.test.InitApp.producerFactory(InitApp.kt:58) ~[main/:na]
at de.mikatiming.de.test.InitApp$$EnhancerBySpringCGLIB$$c3b698bb.CGLIB$producerFactory$10(<generated>) ~[main/:na]
at de.mikatiming.de.test.InitApp$$EnhancerBySpringCGLIB$$c3b698bb$$FastClassBySpringCGLIB$$b315799f.invoke(<generated>) ~[main/:na]
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228) ~[spring-core-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:365) ~[spring-context-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at de.mikatiming.de.test.InitApp$$EnhancerBySpringCGLIB$$c3b698bb.producerFactory(<generated>) ~[main/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_172]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_172]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_172]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_172]
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
... 24 common frames omitted
Update 3:
I just found out that when i remove a specific bean from my InitApp:
#Bean
fun placeHolderConfigurer(): PropertySourcesPlaceholderConfigurer {
return PropertySourcesPlaceholderConfigurer()
}
i get an other error message:
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'de.mikatiming.messageengine.configuration.ApplicationProperties' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {#org.springframework.beans.factory.annotation.Autowired(required=true)}
So it looks like it is an issue with this bean!

Answer 1

I managed to get it working:
Annotations
#Service
#Configuration
#EnableConfigurationProperties
#EnableTransactionManagement
class AppConfig {
ApplicationProperties:
#ConfigurationProperties("mt")
class ApplicationProperties {
ApplicationClass:
#SpringBootApplication
#EnableConfigurationProperties(ApplicationProperties::class)
abstract class MessageengineApplication
Beans
i needed to remove the following Bean from AppConfig:
#Bean
fun placeHolderConfigurer(): PropertySourcesPlaceholderConfigurer {
return PropertySourcesPlaceholderConfigurer()
}

Answer 2

This is ought to work:
#Component
#EnableTransactionManagement
#Configuration
#EnableConfigurationProperties(ApplicationProperties::class)
class InitApp {
#Autowired
lateinit var conf: ApplicationProperties
// ...
}
#ConfigurationProperties("mt")
class ApplicationProperties {
var initDatabase: Boolean? = null
val kafka = Kafka()
class Kafka {
lateinit var host: String
lateinit var port: String
}
}
Note that you need to put #Configuration on InitApp, not on ApplicationProperties.
I also have these in my build.gradle:
apply plugin: 'kotlin-spring'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'
depencencies {
compile "org.springframework.boot:spring-boot-starter-web"
compileOnly "org.springframework.boot:spring-boot-configuration-processor"
}
dependencyManagement {
imports { mavenBom("org.springframework.boot:spring-boot-dependencies:${springBootVersion}") }
}
You need the "org.springframework.boot:spring-boot-configuration-processor" dependency in place in order for this whole thing to work.

Answer 3

#EnableConfigurationProperties is usually put on classes marked with #Configuration annotation.
In the code snippet class InitApp should be marked as a #Configuration and then you can (I don't know Kotlin, so I'll provide a java equivalent):
#Configuration
#EnableTransactionManagement
#EnableConfigurationProperties(ApplicationProperties.class)
public class InitApp {
#Bean
public <<BeanThatYouNeed>> kafkaConsumer(ApplicationProperties props) {
log.info(props.getKafka().getHost());
}
}

Answer 4

you dont need those #Configuration, #ConfigurationProperties("mt") in the header of class ApplicationProperties
you can use #Value annotation to directly get the props from application.properties file
`
#Component
#EnableTransactionManagement
class InitApp {
#Autowired
lateinit var conf: ApplicationProperties
#Bean
fun createKafkaConsumer(#Value("${mt.kafka.host}") String host,
#Value("${mt.kafka.host}") String port) {
//you have host, port now
}
}
`