Hibernate: LazyInitializationException: could not initialize proxy - no Session

Question

board entity and member entity is not association mapping

board entity class...

@Entity(name = "BOARD")
@Table
@SequenceGenerator(name = "BOARD_SEQ_GENERATOR"
                    , sequenceName = "BOARD_SEQ"
                    , initialValue = 1)
public class BoardEntity {

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE
                    , generator = "BOARD_SEQ_GENERATOR")
    private long idx;

    @Lob
    private String contents;

    private String title;

    private long insNo;

    @Temporal(TemporalType.TIMESTAMP)
    private Date insDate;

    private long uptNo;

    @Temporal(TemporalType.TIMESTAMP)
    private Date uptDate;

    @Transient
    private String insName;
    .....
    getter / setter

member entity class...

@Entity
@Table(name = "MEMBER")
@SequenceGenerator(name = "MEMBERIDX_SEQ_GENERATOR"
                    , sequenceName = "MEMBERIDX_SEQ"
                    , initialValue = 1)
public class MemberEntity implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE
                    , generator = "MEMBERIDX_SEQ_GENERATOR")
    private long memberIdx;

    @Column(nullable = false)
    private String id;

    @Column(nullable = false)
    private String pwd;

    @Column(nullable = false)
    private String name;

    @Column(nullable = false)
    private int age;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(nullable = false)
    private Date insDate;
    .....
    getter / setter

MemberRepository class code...

@Repository
public interface MemberRepository extends JpaRepository<MemberEntity, Long> {

    @Query("select m from MemberEntity m where m.id=:id")
    public MemberEntity getMemberIDbyId(@Param("id") String id);
}

MemberService class code...

@Service
@Transactional
public class MemberService {

    @Autowired private MemberRepository memberRepository;

    public void addMember(MemberEntity member) {
        memberRepository.save(member);
    }

    public MemberEntity getMember(Long memberIdx) {
        return memberRepository.getOne(memberIdx);
    }
}

BoardController class code...

@Controller
@RequestMapping(value = "/board")
public class BoardController {

    @Autowired 
    private BoardService boardService;

    @Autowired
    private MemberService memberService;

    @RequestMapping(value = "/list", method = RequestMethod.GET)
    public String BoardList(HttpServletRequest req, HttpServletResponse resp, Model model) throws Exception {

        List<BoardEntity> resutlList = boardService.getBoardList();

        //resutlList.forEach(System.out::println);

        for (BoardEntity item : resutlList) {
            MemberEntity memberEntity = memberService.getMember(item.getInsNo());
            item.setInsName(memberEntity.getName());
        }

        model.addAttribute("boardList", resutlList);

        return "board/boardList";
    }
}

ErrorMessage

심각: Servlet.service() for servlet [dispatcher] in context with path [] threw exception [Request processing failed; nested exception is org.hibernate.LazyInitializationException: could not initialize proxy - no Session] with root cause org.hibernate.LazyInitializationException: could not initialize proxy - no Session at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:147) at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:260) at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:68) at com.knk.spring4.entity.member.MemberEntity_$$_jvst201_0.getName(MemberEntity_$$_jvst201_0.java) at com.knk.spring4.controller.board.BoardController.BoardList(BoardController.java:70) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221) at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:114) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Unknown Source)

ERD

The InsNo and UptNo columns in the Board table contain the MemberIdx values of the member who created and edited the post.

I want to import the ID column of the membership table using the InsNo column or the UptNo column of the bulletin board table.

How do I handle the current error if there is no mapping of associations?

See my answer on "Could not initialize proxy - no Session".

Murat Yıldız
– Murat Yıldız

2023-01-25 11:59:47 +00:00
Commented Jan 25, 2023 at 11:59 — Murat Yıldız
– Murat Yıldız, Commented Jan 25, 2023 at 11:59

Baptiste Beauvais · Accepted Answer · 2018-01-05 08:36:35Z

It's because you are using the JpaRepository.getOne method to retrieve members. According to the JPA repository Javadoc :

T getOne(ID id)

Returns a reference to the entity with the given identifier.

See Also:

EntityManager.getReference(Class, Object)

And and the EntityManager Javadoc:

T getReference(Class entityClass, Object primaryKey)

Get an instance, whose state may be lazily fetched.

Basically JpaRepository.getOne doesn't return an object build from a fetched database record but a proxy referencing the record that will get initialize on the first access to any member other than the refering id. So when you call MemberEntity.getName when the Session/EntityManager you get the LazyException when the proxy try to fetch the record.

To fix it in your case you have multiple option:

Using a OpenSessionInViewFilter to keep the session on the entire request, this one is an anti-pattern and not recommended
You can use the Hibernate annotation @Lazy and set the lazy property to false (it works in other similar case, not sure it will works here). Cons here is the annotation is not a JPA's one, so you'll tie your project tot he implementation and not the specification.
You can manually trigger the proxy when the Session/EntityManager is still open by calling any member.
The CrudReposiroty.findOne method return the object and not a proxy if i remember correctly.

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