JsonMappingException：无法初始化代理-没有会话

Z时代
2024-01-10
分类：问答

我正在构建使用并返回JSON的RESTful

Web服务。当我尝试通过服务层从数据库中获取ESRBRating对象时，遇到了以下堆栈跟踪。但是，当我将Spring Data

JPA存储库直接注入到控制器，并使用该ID通过ID获取ESRBRating时，它可以正常工作。但是，当通过服务层进行调用时，它不起作用。我在下面提供了堆栈跟踪和代码。有人可以向我解释为什么通过服务层而不是直接通过Spring

Data JPA存储库时会发生这种情况吗？我该如何解决这个问题？

堆栈跟踪

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

控制者

@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> {
}

模型

@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();
    }
}

此控制器代码可以正常工作，可以直接遍历存储库。

@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);
    }
}

}

更新：

我遵循Randall Harleigh的建议，并使用@JsonIgnore设置了反向集合。但是现在我得到了完全不同的堆栈跟踪。现在看来Jackson /

Spring不知道如何序列化ESRBRating。关于这个有什么提示吗？

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2：

我最终将@Proxy（lazy = false）放在ESRBRating类上，现在可以正常使用了。但是我很好奇这会对性能产生什么样的影响？

@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();
    }
}

根据要求，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();
    }
}