如何保存带有额外列的多对多映射的对象？特别栏目是"审批"。对于多对多注释，我只调用了setUsersDocuments(users)，它工作正常...如何使其与额外的列一起使用？
公文
@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;
多对多表
@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：未成功完全保存对象 - 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 at com.patrikmaryska.bc_prace.bc_prace.controller.DocumentController.getDocumentFromClient(DocumentController.java：85) ~[classes/：na] at com.patrikmaryska.bc_prace.bc_prace.controller.DocumentController$$FastClassBySpringCGLIB$$3a9de86b.invoke() ~[classes/：na] at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java：218) ~[spring-core-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java：684) ~[spring-aop-5.1.8.RELEASE.jar：5.1.8.RELEASE] at com.patrikmaryska.bc_prace.bc_prace.controller.DocumentController$$EnhancerBySpringCGLIB$$b 46e5706.getDocumentFromClient() ~[classes/：na] at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na：na] at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java：62) ~[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：190) ~[spring-web-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java：138) ~[spring-web-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java：104) ~[spring-webmvc-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java：892) ~[spring-webmvc-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java：797) ~[spring-webmvc-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java：87) ~[spring-webmvc-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java：1039) ~[spring-webmvc-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java：942) ~[spring-webmvc-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java：1005) ~[spring-webmvc-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java：908) ~[spring-webmvc-5.1.8.RELEASE.jar：5.1.8.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java：660) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java：882) ~[spring-webmvc-5.1.8.RELEASE.jar：5.1.8.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java：741) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java：231) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java：166) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java：53) ~[tomcat-embed-websocket-9.0.21.jar：9.0.21] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java：193) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java：166) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.springframework.boot.actuate.web.trace.servlet.HttpTraceFilter.doFilterInternal(HttpTraceFilter.java：88) ~[spring-boot-actuator-2.1.6.RELEASE.jar：2.1.6.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java：109) ~[spring-web-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java：193) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java：166) ~[tomcat-embed-core-9.0.21.jar：9.0.21]at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java：320) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java：127) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java：91) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java：334) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java：119) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java：334) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java：137) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java：334) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java：170) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java：334) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java：63) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java：334) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.oauth2.provider.authentication.OAuth2AuthenticationProcessingFilter.doFilter(OAuth2AuthenticationProcessingFilter.java：176) ~[spring-security-oauth2-2.3.4.RELEASE.jar：na] at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java：334) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java：116) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java：334) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java：74) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java：109) ~[spring-web-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java：334) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java：105) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java：334) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java：56) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java：109) ~[spring-web-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java：334) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java：215) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java：178) ~[spring-security-web-5.1.5.RELEASE.jar：5.1.5.RELEASE] at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java：357) ~[spring-web-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java：270) ~[spring-web-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java：193) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java：166) ~[tomcat-embed-core-9.0.21.jar：9.0.21]at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java：92) ~[spring-web-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java：109) ~[spring-web-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java：193) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java：166) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java：93) ~[spring-web-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java：109) ~[spring-web-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java：193) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java：166) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.filterAndRecordMetrics(WebMvcMetricsFilter.java：114) ~[spring-boot-actuator-2.1.6.RELEASE.jar：2.1.6.RELEASE] at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java：104) ~[spring-boot-actuator-2.1.6.RELEASE.jar：2.1.6.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java：109) ~[spring-web-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java：193) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java：166) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java：200) ~[spring-web-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java：109) ~[spring-web-5.1.8.RELEASE.jar：5.1.8.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java：193) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java：166) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at com.patrikmaryska.bc_prace.bc_prace.config.CorsConfig.doFilter(CorsConfig.java：34) ~[classes/：na] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java：193) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java：166) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java：202) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java：96) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java：490) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java：139) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java：92) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java：74) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java：343) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java：408) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java：66) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java：853) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java：1587) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java：49) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java：1128) ~[na：na] at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java：628) ~[na：na] at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java：61) ~[tomcat-embed-core-9.0.21.jar：9.0.21] at java.base/java.lang.Thread.run(Thread.java：835) ~[na：na]
1)在文档实体中添加级联到用户文档关系：
@OneToMany(mappedBy = "document", cascade= CascadeType.ALL)
private List<UsersDocuments> usersDocuments;
2)您需要以不同的方式设置实体：
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);