如何使用带有额外列的多对多映射保存对象？

Posted 2023-02-26

【中文标题】如何使用带有额外列的多对多映射保存对象？

【英文标题】：How to save object with many-to-many mapping with extra column?

【发布时间】：2019-11-24 23:44:18

【问题描述】：

如何保存具有多对多映射和额外列的对象？专栏为“审批”。使用多对多注释，我只调用了 setUsersDocuments(users) 并且它工作正常......我怎样才能让它与额外的列一起工作？

文档

@JsonIgnore
    @OneToMany(mappedBy = "document")
    private List<UsersDocuments> documentsForUsers;

用户类

@OneToMany(mappedBy = "user", orphanRemoval = true, cascade= CascadeType.ALL)
private List<UsersDocuments> usersDocuments;

PK

@Embeddable
public class UserDocumentsId implements Serializable 

    @Column(name="user_id")
    private long user;

    @Column(name="document_id")
    private long document;

MANY-TO-MANY 表

    @Entity
@Table(name="users_documents")
public class UsersDocuments 

    @EmbeddedId
    private UserDocumentsId id;

    @ManyToOne(fetch = FetchType.LAZY)
    @MapsId("user")
    @JoinColumn(name = "user_id")
    private User user;

    @ManyToOne(fetch = FetchType.LAZY)
    @MapsId("document")
    @JoinColumn(name = "document_id")
    private Document document;

    @Column(name="approval")
    private boolean approval;

保存文档

Document document = new Document(title, desc);
        document.setUploadDatetime(new Date());
        document.setUser(user.get());

        List<User> users = userService.getUsersByRoles(roles);

//        document.setDocumentsForUsers(users); THIS WAS WHEN USING ONLY MANY TO MANY ANNOTATION

        documentService.saveDocument(document);

编辑：未成功保存对象 - document.getDocumentsForUsers().add(userDocuments) NULL。

Optional<User> user = userService.getUserByEmail(createdBy);
        Document document = new Document(title, desc);
        document.setUploadDatetime(new Date());
        document.setUser(user.get());

        List<User> users = userService.getUsersByRoles(roles);

        for(User userx : users)
            UsersDocuments userDocuments = new UsersDocuments();
            UserDocumentsId id = new UserDocumentsId();

            // Construct the Id with user and document
            id.setUser(userx.getId());
            id.setDocument(document.getId());

            userDocuments.setId(id);
            userDocuments.setApproval(true);

            // This is very important for saving and cascading to work.
            document.getDocumentsForUsers().add(userDocuments);
        

        documentService.saveDocument(document);

编辑：错误

java.lang.NullPointerException: null 在 com.patrikmaryska.bc_prace.bc_prace.controller.DocumentController.getDocumentFromClient(DocumentController.java:85) ~[classes/:na] 在 com.patrikmaryska.bc_prace.bc_prace.controller.DocumentController$$FastClassBySpringCGLIB$$3a9de86b.invoke() ~[classes/:na] 在 org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) ~[spring-core-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:684) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 com.patrikmaryska.bc_prace.bc_prace.controller.DocumentController$$EnhancerBySpringCGLIB$$b46e5706.getDocumentFromClient() ~[classes/:na] 在 java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na] 在 java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na] 在 java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na] 在 java.base/java.lang.reflect.Method.invoke(Method.java:567) ~[na:na] 在 org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:892) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1039) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:908) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 javax.servlet.http.HttpServlet.service(HttpServlet.java:660) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.21.jar:9.0.21] 在 org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.springframework.boot.actuate.web.trace.servlet.HttpTraceFilter.doFilterInternal(HttpTraceFilter.java:88) ~[spring-boot-actuator-2.1.6.RELEASE.jar:2.1.6.RELEASE] 在 org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:320) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:127) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:91) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:119) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:137) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:170) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.oauth2.provider.authentication.OAuth2AuthenticationProcessingFilter.doFilter(OAuth2AuthenticationProcessingFilter.java:176) ~[spring-security-oauth2-2.3.4.RELEASE.jar:na] 在 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:116) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:74) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:215) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:178) ~[spring-security-web-5.1.5.RELEASE.jar:5.1.5.RELEASE] 在 org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:357) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:270) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.filterAndRecordMetrics(WebMvcMetricsFilter.java:114) ~[spring-boot-actuator-2.1.6.RELEASE.jar:2.1.6.RELEASE] 在 org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:104) ~[spring-boot-actuator-2.1.6.RELEASE.jar:2.1.6.RELEASE] 在 org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] 在 org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 com.patrikmaryska.bc_prace.bc_prace.config.CorsConfig.doFilter(CorsConfig.java:34) ~[classes/:na] 在 org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:853) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1587) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na] 在 java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na] 在 org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.21.jar:9.0.21] 在 java.base/java.lang.Thread.run(Thread.java:835) ~[na:na]

【问题讨论】：

显示定义多对多依赖关系的映射

您已经拥有UsersDocuments，这似乎是一个实体。在那里添加额外的属性/列有什么问题？

@Maciej Kowalski 完成。抱歉，我复制了坏表。现在应该没问题了。

@Thomas 添加额外的列不是问题，问题是保存它。我不知道如何将其保存到数据库中...

好吧，在保存新文档或与用户的新关系时，您会以某种方式创建UsersDocuments 实体。假设document.setDocumentsForUsers(users); 这样做了，您可以在那里设置附加数据。在任何情况下，您都需要区分创建和保存UserDocuments 以及向该实体添加其他数据。你问的是后者，但我觉得你实际上对前者有问题。如果您在保存 UserDocuments 时一般没有问题，那么我不明白您的问题 - 您能详细说明一下吗？

【参考方案1】：

1) 在 Document 实体中添加级联到 UserDocuments 关系：

@OneToMany(mappedBy = "document", cascade= CascadeType.ALL)
private List<UsersDocuments> usersDocuments;

2) 您需要以不同方式设置实体：

Document document = new Document(title, desc);
document.setUploadDatetime(new Date());

List<User> users = userService.getUsersByRoles(roles);

for(Use user: users)
    UserDocuments userDocuments = new UserDocuments();
    UserDocumentsId id = new UserDocumentsId();

    // Construct the Id with user and document
    id.setUser(user);
    id.setDocument(document);

    userDocuments.setDocumentsId(id);
    userDocuments.setActivtity(true);

    // This is very important for saving and cascading to work.
    document.getUserDocuments().add(userDocuments);


documentService.saveDocument(document);

【讨论】：

我根据您的回答用我的保存对象版本编辑了我的帖子。它抛出 NULL 指针异常...

只需将该列表设置为例如在构造函数中的新 ArrayList 或直接在字段上..

您指的是哪个列表？我不太确定，你现在的意思是什么...... :(

document.getDocumentsForUsers()

我已经这样做了：在 Document() 构造函数中我有：documentsForUsers = new ArrayList(); - 但同样的问题:(