Can't read list property in controller

Question

I try to use list property defined in application.yml in controller. But IllegalArgumentException error occured.

I'm trying to use topics property in IndexController.

application.yml

application:
  topics:
    -
      id: 0
      topic: first topic
    -
      id: 1
      topic: second topic

IndexController.java

...
@Controller
@RequiredArgsConstructor
@EnableConfigurationProperties
public class IndexController {
//    private final Topics topics;

    @Value("${application.topics}")
    @Setter
    private final List<Topic> topics;
...

Topic.java

...
@Data
public class Topic {
    private int id;
    private String topic;
}

Error message

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'indexController': Injection of autowired dependencies failed; nested exception is java.lang.IllegalArgumentException: Could not resolve placeholder 'application.topics' in value "${application.topics}"
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:405) ~[spring-beans-5.3.28.jar:5.3.28]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1431) ~[spring-beans-5.3.28.jar:5.3.28]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:619) ~[spring-beans-5.3.28.jar:5.3.28]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.28.jar:5.3.28]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.28.jar:5.3.28]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.28.jar:5.3.28]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.28.jar:5.3.28]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.28.jar:5.3.28]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:955) ~[spring-beans-5.3.28.jar:5.3.28]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:920) ~[spring-context-5.3.28.jar:5.3.28]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.28.jar:5.3.28]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:147) ~[spring-boot-2.7.13.jar:2.7.13]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:731) ~[spring-boot-2.7.13.jar:2.7.13]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:408) ~[spring-boot-2.7.13.jar:2.7.13]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) ~[spring-boot-2.7.13.jar:2.7.13]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1303) ~[spring-boot-2.7.13.jar:2.7.13]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1292) ~[spring-boot-2.7.13.jar:2.7.13]
    at com.acapella.pella.chat.Application.main(Application.java:10) ~[main/:na]
Caused by: java.lang.IllegalArgumentException: Could not resolve placeholder 'application.topics' in value "${application.topics}"
    at org.springframework.util.PropertyPlaceholderHelper.parseStringValue(PropertyPlaceholderHelper.java:180) ~[spring-core-5.3.28.jar:5.3.28]
    at org.springframework.util.PropertyPlaceholderHelper.replacePlaceholders(PropertyPlaceholderHelper.java:126) ~[spring-core-5.3.28.jar:5.3.28]
    at org.springframework.core.env.AbstractPropertyResolver.doResolvePlaceholders(AbstractPropertyResolver.java:239) ~[spring-core-5.3.28.jar:5.3.28]
    at org.springframework.core.env.AbstractPropertyResolver.resolveRequiredPlaceholders(AbstractPropertyResolver.java:210) ~[spring-core-5.3.28.jar:5.3.28]
    at org.springframework.context.support.PropertySourcesPlaceholderConfigurer.lambda$processProperties$0(PropertySourcesPlaceholderConfigurer.java:191) ~[spring-context-5.3.28.jar:5.3.28]
    at org.springframework.beans.factory.support.AbstractBeanFactory.resolveEmbeddedValue(AbstractBeanFactory.java:936) ~[spring-beans-5.3.28.jar:5.3.28]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1332) ~[spring-beans-5.3.28.jar:5.3.28]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1311) ~[spring-beans-5.3.28.jar:5.3.28]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.resolveFieldValue(AutowiredAnnotationBeanPostProcessor.java:657) ~[spring-beans-5.3.28.jar:5.3.28]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:640) ~[spring-beans-5.3.28.jar:5.3.28]
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:119) ~[spring-beans-5.3.28.jar:5.3.28]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399) ~[spring-beans-5.3.28.jar:5.3.28]
    ... 17 common frames omitted

But if I read list property by using Property Class, It works well. Can you guys tell me the problem?

Check this [question](https://stackoverflow.com/questions/12576156/reading-a-list-from-properties-file-and-load-with-spring-annotation-value) — dauthDaert06, Jul 27 '23 at 13:37
@dauthDaert06 I'm not sure what's your point. But I use yaml not properties file. — Junyoung Yun, Jul 27 '23 at 13:47

score 0 · Answer 1 · answered Jul 27 '23 at 14:17

You can do it in following way

@Configuration
@ConfigurationProperties("application") // full path except last token
@Data
public class ApplicationConfig {

    private List<Topic> topics;     // property name must match YAML attribute
}

then inject this bean into your service or controller.

Example of usage:

@Service
@RequiredArgsConstructor
public class TestService {

    private final ApplicationConfig applicationConfig;

    @PostConstruct
    public void test() {
        applicationConfig.getTopics().forEach(System.out::println);
    }
}

that outputs

Topic(id=0, topic=first topic)
Topic(id=1, topic=second topic)

Thanks for your answer. Is there any way to get property in controller directly not using `ApplicationConfig` class? — Junyoung Yun, Jul 27 '23 at 23:38

Can't read list property in controller

1 Answers1