순환참조 해결..?

@Entity
@Getter
@NoArgsConstructor
public class Post extends Timestamped{
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    public Long id;

    @Column(nullable = false)
    private String title;

    @Column(nullable = false)
    private String username;

    @Column(nullable = false)
    private String content;
    @OrderBy(value = "modifiedAt desc")
    @OneToMany(fetch = FetchType.LAZY)
    private List<Comment> comments = new ArrayList<>();

@Entity
@Getter
@NoArgsConstructor
public class Comment extends Timestamped{
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @Column(nullable = false)
    private String username;

    @Column(nullable = false)
    private String content;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "Post_Id", nullable = false)
    private Post post;

 

코멘트를 작성하려고 하면, 

{

"timestamp": "2023-01-02T12:03:26.590+00:00",

"status": 500,

"error": "Internal Server Error",

"trace": "org.springframework.dao.DataIntegrityViolationException: could not execute statement; SQL [n/a]; constraint [null]\n\tat org.springframework.orm.jpa.vendor.HibernateJpaDialect.convertHibernateAccessException(HibernateJpaDialect.java:270)\n\tat org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:233)\n\tat org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:566)\n\tat org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:743)\n\tat org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:711)\n\tat org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:654)\n\tat org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:407)\n\tat org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:119)\n\tat org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184)\n\tat org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:752)\n\tat org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:703)\n\tat com.example.project_1_post.service.CommentService$$SpringCGLIB$$0.createComment(<generated>)\n\tat com.example.project_1_post.controller.CommentController.createComment(CommentController.java:49)\n\tat java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)\n\tat java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)\n\tat java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)\n\tat java.base/java.lang.reflect.Method.invoke(Method.java:568)\n\tat org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:207)\n\tat org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:152)\n\tat org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117)\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:884)\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797)\n\tat org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)\n\tat org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1080)\n\tat org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:973)\n\tat org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1003)\n\tat org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:906)\n\tat jakarta.servlet.http.HttpServlet.service(HttpServlet.java:731)\n\tat org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:880)\n\tat jakarta.servlet.http.HttpServlet.service(HttpServlet.java:814)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:223)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:158)\n\tat org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:185)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:158)\n\tat org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:185)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:158)\n\tat org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:185)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:158)\n\tat org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:185)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:158)\n\tat org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197)\n\tat org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)\n\tat org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)\n\tat org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:119)\n\tat org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)\n\tat org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)\n\tat org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357)\n\tat org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:400)\n\tat org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)\n\tat org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861)\n\tat org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1739)\n\tat org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)\n\tat org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)\n\tat org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)\n\tat org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)\n\tat java.base/java.lang.Thread.run(Thread.java:833)\nCaused by: org.hibernate.exception.ConstraintViolationException: could not execute statement\n\tat org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:60)\n\tat org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:56)\n\tat org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:109)\n\tat org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:95)\n\tat org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:200)\n\tat org.hibernate.engine.jdbc.batch.internal.NonBatchingBatch.addToBatch(NonBatchingBatch.java:39)\n\tat org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3386)\n\tat org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3991)\n\tat org.hibernate.action.internal.EntityInsertAction.execute(EntityInsertAction.java:103)\n\tat org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:612)\n\tat org.hibernate.engine.spi.ActionQueue.lambda$executeActions$1(ActionQueue.java:483)\n\tat java.base/java.util.LinkedHashMap.forEach(LinkedHashMap.java:721)\n\tat org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:480)\n\tat org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:329)\n\tat org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:39)\n\tat org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:107)\n\tat org.hibernate.internal.SessionImpl.doFlush(SessionImpl.java:1422)\n\tat org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:476)\n\tat org.hibernate.internal.SessionImpl.flushBeforeTransactionCompletion(SessionImpl.java:2233)\n\tat org.hibernate.internal.SessionImpl.beforeTransactionCompletion(SessionImpl.java:1929)\n\tat org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.beforeTransactionCompletion(JdbcCoordinatorImpl.java:439)\n\tat org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.beforeCompletionCallback(JdbcResourceLocalTransactionCoordinatorImpl.java:183)\n\tat org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.commit(JdbcResourceLocalTransactionCoordinatorImpl.java:281)\n\tat org.hibernate.engine.transaction.internal.TransactionImpl.commit(TransactionImpl.java:101)\n\tat org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:562)\n\t... 60 more\nCaused by: org.h2.jdbc.JdbcSQLIntegrityConstraintViolationException: NULL not allowed for column \"USERNAME\"; SQL statement:\ninsert into comment (content, created_at, modified_at, post_id, username, id) values (?, ?, ?, ?, ?, ?) [23502-214]\n\tat org.h2.message.DbException.getJdbcSQLException(DbException.java:508)\n\tat org.h2.message.DbException.getJdbcSQLException(DbException.java:477)\n\tat org.h2.message.DbException.get(DbException.java:223)\n\tat org.h2.message.DbException.get(DbException.java:199)\n\tat org.h2.table.Column.validateConvertUpdateSequence(Column.java:365)\n\tat org.h2.table.Table.convertInsertRow(Table.java:926)\n\tat org.h2.command.dml.Insert.insertRows(Insert.java:167)\n\tat org.h2.command.dml.Insert.update(Insert.java:135)\n\tat org.h2.command.dml.DataChangeStatement.update(DataChangeStatement.java:74)\n\tat org.h2.command.CommandContainer.update(CommandContainer.java:169)\n\tat org.h2.command.Command.executeUpdate(Command.java:252)\n\tat org.h2.jdbc.JdbcPreparedStatement.executeUpdateInternal(JdbcPreparedStatement.java:209)\n\tat org.h2.jdbc.JdbcPreparedStatement.executeUpdate(JdbcPreparedStatement.java:169)\n\tat com.zaxxer.hikari.pool.ProxyPreparedStatement.executeUpdate(ProxyPreparedStatement.java:61)\n\tat com.zaxxer.hikari.pool.HikariProxyPreparedStatement.executeUpdate(HikariProxyPreparedStatement.java)\n\tat org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:197)\n\t... 80 more\n",

"message": "could not execute statement; SQL [n/a]; constraint [null]",

"path": "/api/1/newcomment"

}

 

내가 보냈던 요청

{

"content" : "안녕112"

}

 

이렇게 바꿈

{

"username" : "admin",

"content" : "안녕112"

}

 

아놔 그랬더니 되네?

 

생각해보니 username을 Nullable = False 로 해놨는데 내가 내용만 보냈었다..

 

 

순환참조를 막으려면 Dto에 담아서 반환?

왜 바로 리턴할 때만 Dto에 값이 담아지지?

 

Post post = postRepository.findById(id).get();

optional 안주고 이렇게 할 수 있구나 .get()을 붙이면