Spring MVC JSONMap异常错误：无法初始化代理-无会话

mrwjdhj3  于 2022-11-14  发布在  Spring
关注(0)|答案(6)|浏览(155)

我正在构建一个使用和返回JSON的REST风格的Web服务。当我尝试通过服务层从数据库中提取ESRBRAating对象时，遇到了以下堆栈跟踪。但是，当我将Spring Data JPA存储库直接注入控制器并使用它按ID提取ESRBRAating时，它工作正常。但是，当通过服务层调用时，它不工作。我已经提供了堆栈跟踪和下面的代码。有人能给我解释一下为什么在通过服务层时会发生这种情况，而在直接通过Spring Data JPA存储库时不会发生这种情况吗？我该如何解决这个问题？
堆栈追踪

Caused by: org.hibernate.LazyInitializationException: could not initialize proxy - no Session
    at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:165)
    at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:286)
    at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:185)
    at net.jkratz.igdb.model.ESRBRating_$$_jvst319_0.getId(ESRBRating_$$_jvst319_0.java)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:466)
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:639)
    ... 76 more

主计长

@RestController
@RequestMapping(produces = "application/json", value="/esrbrating")
public class ESRBRatingController {

    @Inject
    ESRBRatingService esrbRatingService;

    @Inject
    ESRBRatingRepository esrbRatingRepository;

    private Logger logger = LoggerFactory.getLogger(getClass());

    /**
     * Returns all ESRB ratings in database
     * 
     * @return List of ESRBRating objects
     * @see ESRBRating
     */
    @RequestMapping(value = {"","/"}, method = RequestMethod.GET)
    public ResponseEntity<List<ESRBRating>> getESRBRatings() {
        List<ESRBRating> esrbRatings = esrbRatingService.getESRBRatings();
        return new ResponseEntity<>(esrbRatings, HttpStatus.OK);
    }

    /**
     * Returns a single ESRB rating object if exists, otherwise returns HTTP status code 404
     *
     * @param id ID of the ESRB Rating
     * @return ESRB Rating when found
     * @see ESRBRating
     */
    @RequestMapping(value = "/{id}", method = RequestMethod.GET)
    public ResponseEntity<?> getUser(@PathVariable("id") Long id) {
        logger.debug("Attempting to fetch ESRB rating with ID: {}", id);
        ESRBRating esrbRating = esrbRatingService.getESRBRating(id);
        //ESRBRating esrbRating = esrbRatingRepository.findOne(id);

        if (esrbRating == null) {
            return new ResponseEntity<>("ESRB Rating not found", HttpStatus.NOT_FOUND);
        } else {
            return new ResponseEntity<>(esrbRating, HttpStatus.OK);
        }
    }

}

服务

@Service
@Transactional
public class ESRBRatingServiceImpl implements ESRBRatingService {

    @Value("#{paging.games.maxPageSize}")
    private static int DEFAULT_PAGE_SIZE;

    @Value("#{paging.games.maxPageSize}")
    private static int MAX_PAGE_SIZE;

    @Inject
    private ESRBRatingRepository esrbRatingRepository;

    @Override
    public List<ESRBRating> getESRBRatings() {
        List<ESRBRating> ratings =  esrbRatingRepository.findAll();
        return ratings;
    }

    @Override
    public ESRBRating getESRBRating(Long id) {
        return esrbRatingRepository.getOne(id);
    }

    @Override
    public ESRBRating saveESRBRating(ESRBRating esrbRating) {
        return esrbRatingRepository.saveAndFlush(esrbRating);
    }

    @Override
    public boolean deleteESRBRating(Long id) {
        esrbRatingRepository.delete(id);
        return true;
    }
}

资料档案库

package net.jkratz.igdb.repository;

import net.jkratz.igdb.model.ESRBRating;

import org.springframework.data.jpa.repository.JpaRepository;

public interface ESRBRatingRepository extends JpaRepository<ESRBRating, Long> {

}

型号

@Entity
@Table(name = "esrb_rating", schema = "igdb")
@JsonIgnoreProperties(ignoreUnknown = true)
public class ESRBRating implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @NotNull
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id", nullable = false)
    private Long id;

    @NotNull
    @Size(min = 1, max = 255)
    @Column(name = "title", nullable = false, length = 255)
    private String title;

    @Size(max = 65535)
    @Column(length = 65535)
    private String description;

    @OneToMany(cascade = CascadeType.ALL, mappedBy = "esrbRating")
    private List<Game> games;

    public ESRBRating() {
    }

    public ESRBRating(Long id, String title, String description) {
        this.id = id;
        this.title = title;
        this.description = description;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        ESRBRating that = (ESRBRating) o;

        return Objects.equal(this.id, that.id) &&
                Objects.equal(this.title, that.title) &&
                Objects.equal(this.description, that.description);
    }

    @Override
    public int hashCode() {
        return Objects.hashCode(id, title, description);
    }

    @Override
    public String toString() {
        return Objects.toStringHelper(this)
                .add("id", id)
                .add("title", title)
                .add("description", description)
                .toString();
    }
}

这个控制器代码工作正常，直接通过存储库。

@RestController
@RequestMapping(produces = "application/json", value="/esrbrating")
public class ESRBRatingController {

@Inject
ESRBRatingService esrbRatingService;

@Inject
ESRBRatingRepository esrbRatingRepository;

private Logger logger = LoggerFactory.getLogger(getClass());

/**
 * Returns all ESRB ratings in database
 * 
 * @return List of ESRBRating objects
 * @see ESRBRating
 */
@RequestMapping(value = {"","/"}, method = RequestMethod.GET)
public ResponseEntity<List<ESRBRating>> getESRBRatings() {
    List<ESRBRating> esrbRatings = esrbRatingService.getESRBRatings();
    return new ResponseEntity<>(esrbRatings, HttpStatus.OK);
}

/**
 * Returns a single ESRB rating object if exists, otherwise returns HTTP status code 404
 *
 * @param id ID of the ESRB Rating
 * @return ESRB Rating when found
 * @see ESRBRating
 */
@RequestMapping(value = "/{id}", method = RequestMethod.GET)
public ResponseEntity<?> getUser(@PathVariable("id") Long id) {
    logger.debug("Attempting to fetch ESRB rating with ID: {}", id);
    ESRBRating esrbRating = esrbRatingRepository.findOne(id);

    if (esrbRating == null) {
        return new ResponseEntity<>("ESRB Rating not found", HttpStatus.NOT_FOUND);
    } else {
        return new ResponseEntity<>(esrbRating, HttpStatus.OK);
    }
}

}
最新消息：
我听从了Randall Harleigh的建议，用@JsonIgnore设置了反向集合。但是现在我得到了一个完全不同的堆栈跟踪。现在Jackson/ Spring似乎不知道如何序列化ESRBRAating。对此有什么提示吗？

org.springframework.http.converter.HttpMessageNotWritableException: Could not write content: No serializer found for class org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) ) (through reference chain: net.jkratz.igdb.model.ESRBRating_$$_jvstb5c_0["handler"]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: No serializer found for class org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) ) (through reference chain: net.jkratz.igdb.model.ESRBRating_$$_jvstb5c_0["handler"])
    at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.writeInternal(AbstractJackson2HttpMessageConverter.java:238)
    at org.springframework.http.converter.AbstractHttpMessageConverter.write(AbstractHttpMessageConverter.java:208)
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:158)
    at org.springframework.web.servlet.mvc.method.annotation.HttpEntityMethodProcessor.handleReturnValue(HttpEntityMethodProcessor.java:138)
    at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:71)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:122)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:781)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:721)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:118)
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:154)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:150)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.authentication.ui.DefaultLoginPageGeneratingFilter.doFilter(DefaultLoginPageGeneratingFilter.java:155)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:199)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:110)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:50)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192)
    at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:344)
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:261)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)
Caused by: com.fasterxml.jackson.databind.JsonMappingException: No serializer found for class org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) ) (through reference chain: net.jkratz.igdb.model.ESRBRating_$$_jvstb5c_0["handler"])
    at com.fasterxml.jackson.databind.ser.impl.UnknownSerializer.failForEmpty(UnknownSerializer.java:59)
    at com.fasterxml.jackson.databind.ser.impl.UnknownSerializer.serialize(UnknownSerializer.java:26)
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:505)
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:639)
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:152)
    at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:114)
    at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:1887)
    at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.writeInternal(AbstractJackson2HttpMessageConverter.java:231)
    ... 72 more

更新二：
我最后在ESRBRAating类上放置了@Proxy（lazy = false），现在它工作得很好。

@Entity
@Table(name = "esrb_rating", schema = "igdb")
@JsonIgnoreProperties(ignoreUnknown = false)
@Proxy(lazy = false)
public class ESRBRating implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @NotNull
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id", nullable = false)
    private Long id;

    @NotNull
    @Size(min = 1, max = 255)
    @Column(name = "title", nullable = false, length = 255)
    private String title;

    @Size(max = 65535)
    @Column(length = 65535)
    private String description;

    @OneToMany(cascade = CascadeType.ALL, mappedBy = "esrbRating")
    private List<Game> games;

    public ESRBRating() {
    }

    public ESRBRating(Long id, String title, String description) {
        this.id = id;
        this.title = title;
        this.description = description;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    @JsonIgnore
    public List<Game> getGames() {
        return games;
    }

    public void setGames(List<Game> games) {
        this.games = games;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        ESRBRating that = (ESRBRating) o;

        return Objects.equal(this.id, that.id) &&
                Objects.equal(this.title, that.title) &&
                Objects.equal(this.description, that.description);
    }

    @Override
    public int hashCode() {
        return Objects.hashCode(id, title, description);
    }

    @Override
    public String toString() {
        return Objects.toStringHelper(this)
                .add("id", id)
                .add("title", title)
                .add("description", description)
                .toString();
    }
}

按要求这里是游戏类

@Entity
@Table(name = "game", schema = "igdb",
        indexes = {@Index(name = "idx_game_title", columnList = ("title"), unique = false),
                @Index(name = "idx_game_developer", columnList = ("developer"), unique = false),
                @Index(name = "idx_game_publisher", columnList = ("publisher"), unique = false)})
@JsonIgnoreProperties(ignoreUnknown = true)
public class Game implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @NotNull
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id", nullable = false)
    private Long id;

    @NotNull
    @Size(min = 1, max = 255)
    @Column(name = "title", nullable = false, length = 255)
    private String title;

    @Size(max = 65535)
    @Column(name = "description", length = 65535)
    private String description;

    @Size(max = 255)
    @Column(name = "developer", length = 255)
    private String developer;

    @Size(max = 255)
    @Column(name = "publisher", length = 255)
    private String publisher;

    @NotNull
    @Size(max = 4)
    @Column(name = "players", nullable = false)
    private short players;

    @NotNull
    @Column(name = "cooperative", nullable = false)
    private boolean cooperative;

    @NotNull
    @Column(name = "release_date", nullable = false)
    @Temporal(TemporalType.DATE)
    private Date releaseDate;

    @Size(max = 255)
    @Column(name = "image", length = 255)
    private String image;

    @JoinColumn(name = "esrb_rating_id", referencedColumnName = "id", nullable = false)
    @ManyToOne(optional = false, fetch = FetchType.EAGER)
    private ESRBRating esrbRating;   

    @OneToMany(cascade = CascadeType.ALL, mappedBy = "game")
    private List<GamePlatformMap> gamePlatformMap;

    @OneToMany(cascade = CascadeType.ALL, mappedBy = "game")
    private List<GameGenreMap> gameGenreMap;

    public Game() {

    }

    public Game(Long id, String title, String description, String developer,
            String publisher, short players, boolean cooperative,
            Date releaseDate, String image, ESRBRating esrbRating) {
        super();
        this.id = id;
        this.title = title;
        this.description = description;
        this.developer = developer;
        this.publisher = publisher;
        this.players = players;
        this.cooperative = cooperative;
        this.releaseDate = releaseDate;
        this.image = image;
        this.esrbRating = esrbRating;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public String getDeveloper() {
        return developer;
    }

    public void setDeveloper(String developer) {
        this.developer = developer;
    }

    public String getPublisher() {
        return publisher;
    }

    public void setPublisher(String publisher) {
        this.publisher = publisher;
    }

    public short getPlayers() {
        return players;
    }

    public void setPlayers(short players) {
        this.players = players;
    }

    public boolean isCooperative() {
        return cooperative;
    }

    public void setCooperative(boolean cooperative) {
        this.cooperative = cooperative;
    }

    public Date getReleaseDate() {
        return releaseDate;
    }

    public void setReleaseDate(Date releaseDate) {
        this.releaseDate = releaseDate;
    }

    public String getImage() {
        return image;
    }

    public void setImage(String image) {
        this.image = image;
    }

    public ESRBRating getEsrbRating() {
        return esrbRating;
    }

    public void setEsrbRating(ESRBRating esrbRating) {
        this.esrbRating = esrbRating;
    }

    @JsonIgnore
    public List<GamePlatformMap> getGamePlatformMap() {
        return gamePlatformMap;
    }

    public void setGamePlatformMap(List<GamePlatformMap> gamePlatformMap) {
        this.gamePlatformMap = gamePlatformMap;
    }

    @JsonIgnore
    public List<GameGenreMap> getGameGenreMap() {
        return gameGenreMap;
    }

    public void setGameGenreMap(List<GameGenreMap> gameGenreMap) {
        this.gameGenreMap = gameGenreMap;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        Game that = (Game) o;

        return Objects.equal(this.id, that.id) &&
                Objects.equal(this.title, that.title) &&
                Objects.equal(this.description, that.description) &&
                Objects.equal(this.developer, that.developer) &&
                Objects.equal(this.publisher, that.publisher) &&
                Objects.equal(this.players, that.players) &&
                Objects.equal(this.cooperative, that.cooperative) &&
                Objects.equal(this.releaseDate, that.releaseDate) &&
                Objects.equal(this.image, that.image) &&
                Objects.equal(this.esrbRating, that.esrbRating);
    }

    @Override
    public int hashCode() {
        return Objects.hashCode(id, title, description, developer, publisher, players,
                cooperative, releaseDate, image, esrbRating);
    }

    @Override
    public String toString() {
        return Objects.toStringHelper(this)
                .add("id", id)
                .add("title", title)
                .add("description", description)
                .add("developer", developer)
                .add("publisher", publisher)
                .add("players", players)
                .add("cooperative", cooperative)
                .add("releaseDate", releaseDate)
                .add("image", image)
                .add("esrbRating", esrbRating)
                .toString();
    }
}
spring-mvc

6条答案

按热度按时间
carvr3hs

carvr3hs1#

这通常发生在通过@Responsebody返回对象时（或者在您的情况下通过@RestController的响应主体），并且对象正在序列化，但在LAZY集合中有尚未引用的子对象。（就像你在@Service中启动的那个）你可以让你的获取策略EAGER，在你的事务中通过引用引入你的集合，或者让你的LAZY集合JSON Transient。

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x6492ojm

x6492ojm2#

首先根据jackson-core版本下载jackson-datatype-hibernate4-2.2.3.jar或更高版本，然后在config文件中使用这段代码，就可以使用抓取策略LAZY而不会出错。

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.datatype.hibernate4.Hibernate4Module;

public class ApplicationConfig extends WebMvcConfigurerAdapter
{
public MappingJackson2HttpMessageConverter jacksonMessageConverter(){
    MappingJackson2HttpMessageConverter messageConverter = new  MappingJackson2HttpMessageConverter();

    ObjectMapper mapper = new ObjectMapper();
    //Registering Hibernate4Module to support lazy objects
    mapper.registerModule(new Hibernate4Module());

    messageConverter.setObjectMapper(mapper);
    return messageConverter;

}

@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
    //Here we add our custom-configured HttpMessageConverter
    converters.add(jacksonMessageConverter());
    super.configureMessageConverters(converters);
}
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vx6bjr1n

vx6bjr1n3#

@JsonIgnore注解可能会解决您的问题，但是它会导致您最初设置为FetchType.LAZY的特定字段被完全忽略。

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o2g1uqev

o2g1uqev4#

我也遇到过同样的错误，但没有答案帮我。
看起来问题出在jpa.open-in-view=false中。我已经删除了它，现在一切都按预期工作。

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tjrkku2a

tjrkku2a5#

通过将以下内容添加到gradle.build，解决了Sping Boot 2.3.0的问题：
实现'com.fasterxml.Jackson.数据类型：jackson-数据类型-休眠5：2.11.3'
并声明另一个bean：

@Bean
public Module datatypeHibernateModule() {
    return new Hibernate5Module();
}
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jdgnovmf

jdgnovmf6#

在我的情况下，我只需要添加

spring.jpa.properties.hibernate.enable_lazy_load_no_trans=true

在我的application.properties文件中

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