spring boot lazy-loading 사용시 에러

spring boot를 사용하여 새로운 프로젝트를 구성하고 있다.

@OneToMany(mappedBy = "configs" , fetch=FetchType.LAZY)
private List<Category> categories;

LAZY Fetch 전략을 사용해서 categories 들을 읽어오는 로직을 사용했는데 

아래와 같이 에러가 발생했다. 

failed to lazily initialize a collection of role .... could not initialize proxy - no Session

 

application.yml에 아래와 같은 설정을 추가했지만 동일한 에러 발생

spring.jpa.open-in-view: true 
spring.jpa.properties.hibernate.enable_lazy_load_no_trans=true

JAVA Config 파일에 WebMvcConfigurationSupport을 상속받도록 하고
Spring에서 제공하는 OpenEntityManagerInViewInterceptor 를 추가하여 해결

@Configuration 
public class AdminWebAppConfig extends WebMvcConfigurationSupport {  

  @Override     
  protected void addInterceptors(InterceptorRegistry registry) {     
    registry.addWebRequestInterceptor(openEntityManagerInViewInterceptor()).addPathPatterns("/**");
  }   
  
  @Bean   
  public OpenEntityManagerInViewInterceptor openEntityManagerInViewInterceptor() {     
    return new OpenEntityManagerInViewInterceptor();
  } 
 
}

 

추가내용
spring.jpa.open-in-view: true 설정을 하게 되면 JpaWebConfiguration이 활성화 된다.
( OSIV Interceptor를 registry에 등록하는 소스가 포함되어 있다.)

org.springframework.boot.autoconfigure.orm.jpa.JpaWebConfiguration

@Configuration
@ConditionalOnWebApplication(type = Type.SERVLET)
@ConditionalOnClass(WebMvcConfigurer.class)
@ConditionalOnMissingBean({ OpenEntityManagerInViewInterceptor.class, OpenEntityManagerInViewFilter.class })
@ConditionalOnMissingFilterBean(OpenEntityManagerInViewFilter.class)
@ConditionalOnProperty(prefix = "spring.jpa", name = "open-in-view", havingValue = "true", matchIfMissing = true)
protected static class JpaWebConfiguration {
	// Defined as a nested config to ensure WebMvcConfigurerAdapter is not read when
	// not on the classpath
	@Configuration
	protected static class JpaWebMvcConfiguration implements WebMvcConfigurer {
		private static final Log logger = LogFactory.getLog(JpaWebMvcConfiguration.class);
		private final JpaProperties jpaProperties;
		protected JpaWebMvcConfiguration(JpaProperties jpaProperties) {
			this.jpaProperties = jpaProperties;
		}
		@Bean
		public OpenEntityManagerInViewInterceptor openEntityManagerInViewInterceptor() {
			if (this.jpaProperties.getOpenInView() == null) {
				logger.warn("spring.jpa.open-in-view is enabled by default. "
						+ "Therefore, database queries may be performed during view "
						+ "rendering. Explicitly configure " + "spring.jpa.open-in-view to disable this warning");
			}
			return new OpenEntityManagerInViewInterceptor();
		}
		@Override
		public void addInterceptors(InterceptorRegistry registry) {
			registry.addWebRequestInterceptor(openEntityManagerInViewInterceptor());
		}
	}
}

 

하지만 내가 생성한 Configuration파일에서는 WebMvcConfigurationSupport를 상속받아서 설정했기 때문에
JpaWebConfiguration 을 추가하는 WebMvcAutoConfiguration이  동작하지 않는다.

   WebMvcAutoConfiguration:
      Did not match: 																
         - @ConditionalOnBean (types: org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport; SearchStrategy: all) found beans of type 'org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport' adminWebAppConfig (OnBeanCondition)
      Matched:
         - @ConditionalOnClass found required classes 'javax.servlet.Servlet', 'org.springframework.web.servlet.DispatcherServlet', 'org.springframework.web.servlet.config.annotation.WebMvcConfigurer' (OnClassCondition)
         - found 'session' scope (OnWebApplicationCondition)

 

Configuration을 아래와 같이 변경하면 application.yml에 설정한대로 동작한다.

 

@Configuration 
public class AdminWebAppConfig implements WebMvcConfigurer  {  

}

또는

@EnableWebMvc
@Configuration 
public class AdminWebAppConfig  {  

}