sharding-jdbc Parameter `null` should extends Comparable

Question

Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.transaction.TransactionSystemException: Could not commit JPA transaction; nested exception is javax.persistence.RollbackException: Error while committing the transaction] with root cause

com.dangdang.ddframe.rdb.sharding.exception.ShardingJdbcException: Parameter null should extends Comparable for sharding value.

at com.dangdang.ddframe.rdb.sharding.parsing.parser.context.condition.Condition.getValues(Condition.java:99) ~[sharding-jdbc-core-1.5.4.jar:na]
at com.dangdang.ddframe.rdb.sharding.parsing.parser.context.condition.Condition.getShardingValue(Condition.java:81) ~[sharding-jdbc-core-1.5.4.jar:na]
at com.dangdang.ddframe.rdb.sharding.routing.type.simple.SimpleRoutingEngine.getShardingValues(SimpleRoutingEngine.java:117) ~[sharding-jdbc-core-1.5.4.jar:na]
at com.dangdang.ddframe.rdb.sharding.routing.type.simple.SimpleRoutingEngine.routeTables(SimpleRoutingEngine.java:83) ~[sharding-jdbc-core-1.5.4.jar:na]
at com.dangdang.ddframe.rdb.sharding.routing.type.simple.SimpleRoutingEngine.route(SimpleRoutingEngine.java:67) ~[sharding-jdbc-core-1.5.4.jar:na]
at com.dangdang.ddframe.rdb.sharding.routing.router.ParsingSQLRouter.route(ParsingSQLRouter.java:117) ~[sharding-jdbc-core-1.5.4.jar:na]
at com.dangdang.ddframe.rdb.sharding.routing.router.ParsingSQLRouter.route(ParsingSQLRouter.java:84) ~[sharding-jdbc-core-1.5.4.jar:na]
at com.dangdang.ddframe.rdb.sharding.routing.PreparedStatementRoutingEngine.route(PreparedStatementRoutingEngine.java:57) ~[sharding-jdbc-core-1.5.4.jar:na]
at com.dangdang.ddframe.rdb.sharding.jdbc.core.statement.ShardingPreparedStatement.route(ShardingPreparedStatement.java:149) ~[sharding-jdbc-core-1.5.4.jar:na]
at com.dangdang.ddframe.rdb.sharding.jdbc.core.statement.ShardingPreparedStatement.executeUpdate(ShardingPreparedStatement.java:128) ~[sharding-jdbc-core-1.5.4.jar:na]
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:175) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3032) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3547) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.action.internal.EntityInsertAction.execute(EntityInsertAction.java:89) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:600) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:474) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:337) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:39) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.internal.SessionImpl.doFlush(SessionImpl.java:1437) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:494) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.internal.SessionImpl.flushBeforeTransactionCompletion(SessionImpl.java:3245) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.internal.SessionImpl.beforeTransactionCompletion(SessionImpl.java:2451) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.beforeTransactionCompletion(JdbcCoordinatorImpl.java:473) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.beforeCompletionCallback(JdbcResourceLocalTransactionCoordinatorImpl.java:156) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.access$100(JdbcResourceLocalTransactionCoordinatorImpl.java:38) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.commit(JdbcResourceLocalTransactionCoordinatorImpl.java:231) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.engine.transaction.internal.TransactionImpl.commit(TransactionImpl.java:68) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:536) ~[spring-orm-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:746) ~[spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:714) ~[spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:532) ~[spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:304) ~[spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) ~[spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ~[spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:135) ~[spring-data-jpa-2.0.8.RELEASE.jar:2.0.8.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:61) ~[spring-data-commons-2.0.8.RELEASE.jar:2.0.8.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at com.sun.proxy.$Proxy82.save(Unknown Source) ~[na:na]
at com.init.sharding.jdbc.controller.GoodsController.save(GoodsController.java:28) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209) ~[spring-web-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) ~[spring-web-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) ~[spring-webmvc-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:877) ~[spring-webmvc-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:783) ~[spring-webmvc-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) ~[spring-webmvc-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) ~[spring-webmvc-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974) ~[spring-webmvc-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:866) ~[spring-webmvc-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851) ~[spring-webmvc-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.31.jar:8.5.31]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) ~[spring-web-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) ~[spring-web-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.7.RELEASE.jar:5.0.7.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:496) [tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803) [tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790) [tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1468) [tomcat-embed-core-8.5.31.jar:8.5.31]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.31.jar:8.5.31]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_181]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_181]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.31.jar:8.5.31]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_181]

上面是报错异常，我是参考这篇文章做的DEMO
https://www.cnblogs.com/dalao...
请教一下怎么解决，我的项目可以启动正常，下面的是关键报错异常：
: Servlet.service() for servlet [] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.transaction.TransactionSystemException: Could not commit JPA transaction; nested exception is javax.persistence.RollbackException: Error while committing the transaction] with root cause

com.dangdang.ddframe.rdb.sharding.exception.ShardingJdbcException: Parameter null should extends Comparable for sharding value.

at com.dangdang.ddframe.rdb.sharding.parsing.parser.context.condition.Condition.getValues(Condition.java:99) ~[sharding-jdbc-core-1.5.4.jar:na]