참고 : API 호출 시 무한루프 오류
문제 발생!
사용자의 주문 내역을 불러오는 과정에서 오류가 발생하였다.
com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No serializer found for class org.hibernate.proxy.pojo.bytebuddy.ByteBuddyInterceptor and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain: java.util.ArrayList[0]->jpabook.jpashop.domain.Order["member"]->jpabook.jpashop.domain.Member$HibernateProxy$hkIjGrBD["hibernateLazyInitializer"])
at com.fasterxml.jackson.databind.exc.InvalidDefinitionException.from(InvalidDefinitionException.java:77) ~[jackson-databind-2.11.3.jar:2.11.3]
at com.fasterxml.jackson.databind.SerializerProvider.reportBadDefinition(SerializerProvider.java:1277) ~[jackson-databind-2.11.3.jar:2.11.3]
at com.fasterxml.jackson.databind.DatabindContext.reportBadDefinition(DatabindContext.java:400) ~[jackson-databind-2.11.3.jar:2.11.3]
at com.fasterxml.jackson.databind.ser.impl.UnknownSerializer.failForEmpty(UnknownSerializer.java:71) ~[jackson-databind-2.11.3.jar:2.11.3]
at com.fasterxml.jackson.databind.ser.impl.UnknownSerializer.serialize(UnknownSerializer.java:33) ~[jackson-databind-2.11.3.jar:2.11.3]
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.3.jar:2.11.3]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:755) ~[jackson-databind-2.11.3.jar:2.11.3]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:178) ~[jackson-databind-2.11.3.jar:2.11.3]
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.3.jar:2.11.3]
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:755) ~[jackson-databind-2.11.3.jar:2.11.3]
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:178) ~[jackson-databind-2.11.3.jar:2.11.3]
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:145) ~[jackson-databind-2.11.3.jar:2.11.3]
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:107) ~[jackson-databind-2.11.3.jar:2.11.3]
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:25) ~[jackson-databind-2.11.3.jar:2.11.3]
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider._serialize(DefaultSerializerProvider.java:480) ~[jackson-databind-2.11.3.jar:2.11.3]
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:400) ~[jackson-databind-2.11.3.jar:2.11.3]
at com.fasterxml.jackson.databind.ObjectWriter$Prefetch.serialize(ObjectWriter.java:1512) ~[jackson-databind-2.11.3.jar:2.11.3]
at com.fasterxml.jackson.databind.ObjectWriter.writeValue(ObjectWriter.java:1006) ~[jackson-databind-2.11.3.jar:2.11.3]
at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.writeInternal(AbstractJackson2HttpMessageConverter.java:345) ~[spring-web-5.3.2.jar:5.3.2]
at org.springframework.http.converter.AbstractGenericHttpMessageConverter.write(AbstractGenericHttpMessageConverter.java:104) ~[spring-web-5.3.2.jar:5.3.2]
at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:277) ~[spring-webmvc-5.3.2.jar:5.3.2]
at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:181) ~[spring-webmvc-5.3.2.jar:5.3.2]
at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:78) ~[spring-web-5.3.2.jar:5.3.2]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:124) ~[spring-webmvc-5.3.2.jar:5.3.2]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:894) ~[spring-webmvc-5.3.2.jar:5.3.2]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.2.jar:5.3.2]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.2.jar:5.3.2]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1061) ~[spring-webmvc-5.3.2.jar:5.3.2]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:961) ~[spring-webmvc-5.3.2.jar:5.3.2]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.2.jar:5.3.2]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.2.jar:5.3.2]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) ~[tomcat-embed-core-9.0.41.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.2.jar:5.3.2]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) ~[tomcat-embed-core-9.0.41.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.41.jar:9.0.41]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.2.jar:5.3.2]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.2.jar:5.3.2]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.2.jar:5.3.2]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.2.jar:5.3.2]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.2.jar:5.3.2]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.2.jar:5.3.2]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:888) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1597) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at java.base/java.lang.Thread.run(Thread.java:829) ~[na:na]
@ManyToOne(fetch = LAZY)
@JoinColumn(name = "member_id")
private Member member;
@OneToMany(mappedBy = "order", cascade = CascadeType.ALL)
private List<OrderItem> orderItems = new ArrayList<>();
@OneToOne(fetch = LAZY, cascade = CascadeType.ALL)
@JoinColumn(name = "delivery_id")
private Delivery delivery;위는 Order에서 지연로딩으로 설정되어있는 필드이다.
X To One의 경우는 default가 Eager이기 때문에 Lazy로 설정했고,
X To Many의 경우는 default가 Lazy이다.
참고 : 지연로딩 vs 즉시로딩
즉시로딩(Eager)의 경우 예상치 못한 SQL이 나가거나, N+1의 문제가 발생할 수 있기에 지연로딩(Lazy)를 이용하고 성능 최적화의 경우 fetch join을 이용한다.
@GetMapping("/api/v1/simple-orders")
public List<Order> ordersV1() {
return orderRepository.findAllByString(new OrderSearch());
} 무한루프에서 이용했던 API를 다시 호출해 보겠다.
이 시점에서 또 에러가 발생!!!
Order 객체 정보를 JSON으로 변환하는 과정에서
Order를 serialize해주려는 순간, fetchType이 Lazy이기 때문에
실제 figure객체가 아닌 프록시로 감싸져있는 hibernateLazyInitializer를 serialize(직렬화) 하기 때문에 문제가 발생한다.
프록시 객체는 생성될 때 ByteBuddyInterCeptor 라이브러리를 이용하기 때문에 해당 문제가 발생하는 것이다.
(프록시 객체를 json으로 어떻게 생성할지 몰라 에러가 발생하는 것)
해결 방법
1. Lazy가 아닌 Eager로 fetchType을 변경
-> 즉시로딩을 이용할 시 예상하지 못한 SQL 및 N+1 문제가 발생할 수 있기 때문에 근본적인 해결책이 되지 못한다.
2. Hibernate5Module 을 스프링 빈으로 등록
- build.gradle에 다음 코드 추가
dependencies { implementation 'com.fasterxml.jackson.datatype:jackson-datatype-hibernate5' } - Application에 다음 코드 추가
@Bean Hibernate5Module hibernate5Module() { return new Hibernate5Module(); }
꾸준하게