Spring @PostMapping can’t create entity from provided JSON

I am learning springboot and I’ve encountered problem while creating new entities through POST requests. While creating one entity I can use Json in POST request but while creating others I can’t.

Method working as expected

The one working properly looks like this.

@Entity
@Getter
@Setter
public class AccountingGroup {
  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Long groupId;
  private Long userId;
  private String groupName;
  @OneToMany
  @JoinColumn(name = "groupId", updatable = false, insertable = false)
  List<Participant> participants;
}

I have also created data transfer object for this entity:

@Getter
@Setter
@Builder
public class GroupDto {
  private Long groupId;
  private Long userId;
  private String groupName;
}

and data transfer object mapper:

public class GroupDtoMapper {
  private  GroupDtoMapper() {

  }
  public static List<GroupDto> mapToGroupDto(List<AccountingGroup> groups){
    return groups.stream()
        .map(gr -> mapToDto(gr))
        .collect(Collectors.toList());
  }

  public static GroupDto mapToDto(AccountingGroup group) {
    return GroupDto.builder()
        .groupId(group.getGroupId())
        .userId(group.getUserId())
        .groupName(group.getGroupName())
        .build();
  }

}

controller for creating this entity looks like this:

@RestController
@RequiredArgsConstructor
public class GroupsController {

  private final GroupService groupService;

  @PostMapping(path="/group")
  public GroupDto addAccountingGroup(@RequestBody AccountingGroup group){
    return groupService.addGroup(group);
  }
}

and GroupService looks like this:

@Service
@RequiredArgsConstructor
public class GroupService {

  private final GroupRepository groupRepository;

  public GroupDto addGroup(AccountingGroup group) {
    group.setParticipants(null);
    return GroupDtoMapper.mapToGroupDto(Collections.singletonList(groupRepository.save(group))).get(0);
  }

Swagger-ui console for this method looks like this:swagger-console-group

and the response looks like expected:swagger-response-group

Malfunctioning method

Then I have another entity called Participant that is connected with AccountingGroup through a relation:

@Entity
@Getter
@Setter
public class Participant {
  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Long participantId;
  private String name;
  private Long groupId;

  @OneToMany
  @JoinColumn(name = "expenditureId", updatable = false, insertable = false)
  List<Expenditure> expenditures;

  @OneToMany
  @JoinColumn(name="participantId", updatable = false, insertable = false)
  List<Debtors> owing;
}

it also has it’s data transfer object:

@Getter
@Setter
@Builder
public class ParticipantDto {
  private Long participantId;
  private String name;
  private List<ExpenditureDto> expenditureDto;
}

public class ParticipantDtoMapper {

  private  ParticipantDtoMapper() {

  }
  public static List<ParticipantDto> mapToParticipantDtos(List<Participant> participants) {
    return participants.stream()
        .map(participant -> mapToDtos(participant))
        .collect(Collectors.toList());
  }

  public static ParticipantDto mapToDtos(Participant participant) {
    return ParticipantDto.builder()
        .participantId(participant.getParticipantId())
        .name(participant.getName())
        .build();
  }
}

and controller:

@RestController
@RequiredArgsConstructor
public class ParticiapntsController {
  public final ParticipantService participantService;
  
  @PostMapping(path="/participant")
  public ParticipantDto addParticipant(@RequestBody Participant participant){
    return participantService.addParticipant(participant);
  }
}

@Service
@RequiredArgsConstructor
public class ParticipantService {
 public ParticipantDto addParticipant(Participant participant) {
    groupRepository.findById(participant.getGroupId()).orElseThrow();
    participant.setOwing(null);
    participant.setExpenditures(null);
    return ParticipantDtoMapper.mapToParticipantDtos(Collections.singletonList(participantRepository.save(participant))).get(0);
  }
}

So logic here is similar to this in AccountingGroup. However here I can’t send Json object in the POST request. Swagger-ui console looks like this:swagger-console-participant and the response looks like this:swagger-response-participant So participant is added correctly however I can’t use Json in the requet and I don’t know why. When I tried to make a POST request with json through Python it worked fine for AccountingGroup but for Particiapnt I got this error:

import requests

url = "http://localhost:8080/participant"
params = {"groupId": 4,
          "name": 'next user'}
resp = requests.post(url, json=params)

java.lang.IllegalArgumentException: The given id must not be null!
    at org.springframework.util.Assert.notNull(Assert.java:201) ~[spring-core-5.3.9.jar:5.3.9]
    at org.springframework.data.jpa.repository.support.SimpleJpaRepository.findById(SimpleJpaRepository.java:297) ~[spring-data-jpa-2.5.4.jar:2.5.4]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:78) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Method.java:567) ~[na:na]
    at org.springframework.data.repository.core.support.RepositoryMethodInvoker$RepositoryFragmentMethodInvoker.lambda$new$0(RepositoryMethodInvoker.java:289) ~[spring-data-commons-2.5.4.jar:2.5.4]
    at org.springframework.data.repository.core.support.RepositoryMethodInvoker.doInvoke(RepositoryMethodInvoker.java:137) ~[spring-data-commons-2.5.4.jar:2.5.4]
    at org.springframework.data.repository.core.support.RepositoryMethodInvoker.invoke(RepositoryMethodInvoker.java:121) ~[spring-data-commons-2.5.4.jar:2.5.4]
    at org.springframework.data.repository.core.support.RepositoryComposition$RepositoryFragments.invoke(RepositoryComposition.java:529) ~[spring-data-commons-2.5.4.jar:2.5.4]
    at org.springframework.data.repository.core.support.RepositoryComposition.invoke(RepositoryComposition.java:285) ~[spring-data-commons-2.5.4.jar:2.5.4]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$ImplementationMethodExecutionInterceptor.invoke(RepositoryFactorySupport.java:599) ~[spring-data-commons-2.5.4.jar:2.5.4]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.9.jar:5.3.9]
    at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.doInvoke(QueryExecutorMethodInterceptor.java:163) ~[spring-data-commons-2.5.4.jar:2.5.4]
    at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.invoke(QueryExecutorMethodInterceptor.java:138) ~[spring-data-commons-2.5.4.jar:2.5.4]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.9.jar:5.3.9]
    at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:80) ~[spring-data-commons-2.5.4.jar:2.5.4]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.9.jar:5.3.9]
    at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:123) ~[spring-tx-5.3.9.jar:5.3.9]
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:388) ~[spring-tx-5.3.9.jar:5.3.9]
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:119) ~[spring-tx-5.3.9.jar:5.3.9]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.9.jar:5.3.9]
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:137) ~[spring-tx-5.3.9.jar:5.3.9]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.9.jar:5.3.9]
    at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:174) ~[spring-data-jpa-2.5.4.jar:2.5.4]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.9.jar:5.3.9]
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:97) ~[spring-aop-5.3.9.jar:5.3.9]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.9.jar:5.3.9]
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:215) ~[spring-aop-5.3.9.jar:5.3.9]
    at jdk.proxy2/jdk.proxy2.$Proxy97.findById(Unknown Source) ~[na:na]
    at pl.wzyla.accounting.service.ParticipantService.addParticipant(ParticipantService.java:86) ~[classes/:na]
    at pl.wzyla.accounting.controller.ParticiapntsController.addParticipant(ParticiapntsController.java:38) ~[classes/:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:78) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Method.java:567) ~[na:na]
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:197) ~[spring-web-5.3.9.jar:5.3.9]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:141) ~[spring-web-5.3.9.jar:5.3.9]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106) ~[spring-webmvc-5.3.9.jar:5.3.9]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.3.9.jar:5.3.9]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.9.jar:5.3.9]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.9.jar:5.3.9]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1064) ~[spring-webmvc-5.3.9.jar:5.3.9]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) ~[spring-webmvc-5.3.9.jar:5.3.9]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.9.jar:5.3.9]
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909) ~[spring-webmvc-5.3.9.jar:5.3.9]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:681) ~[tomcat-embed-core-9.0.52.jar:4.0.FR]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.9.jar:5.3.9]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.52.jar:4.0.FR]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.52.jar:9.0.52]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.9.jar:5.3.9]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.9.jar:5.3.9]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.9.jar:5.3.9]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.9.jar:5.3.9]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.9.jar:5.3.9]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.9.jar:5.3.9]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1726) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.52.jar:9.0.52]
    at java.base/java.lang.Thread.run(Thread.java:831) ~[na:na]

Answer

I finally solved this problem. In GroupsController I had the following import

import org.springframework.web.bind.annotation.RequestBody;

and in ParticipantsController

import io.swagger.v3.oas.annotations.parameters.RequestBody;

When I set both imports to this one from GroupsController everything works as expected.