在使用模型驱动封装的时候，要保证表单中name属性名和类中属性名一致，否则将会报错如下：
HTTP Status 500 - The given object has a null identifier: cn.itcast.entity.Customer; nested exception is org.hibernate.TransientObjectException: The given object has a null identifier: cn.itcast.entity.Customer type Exception report message The given object has a null identifier: cn.itcast.entity.Customer; nested exception is org.hibernate.TransientObjectException: The given object has a null identifier: cn.itcast.entity.Customer description The server encountered an internal error that prevented it from fulfilling this request. exception org.springframework.dao.InvalidDataAccessApiUsageException: The given object has a null identifier: cn.itcast.entity.Customer; nested exception is org.hibernate.TransientObjectException: The given object has a null identifier: cn.itcast.entity.Customer org.springframework.orm.hibernate5.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:191) org.springframework.orm.hibernate5.HibernateTemplate.doExecute(HibernateTemplate.java:344) org.springframework.orm.hibernate5.HibernateTemplate.executeWithNativeSession(HibernateTemplate.java:309) org.springframework.orm.hibernate5.HibernateTemplate.update(HibernateTemplate.java:643) org.springframework.orm.hibernate5.HibernateTemplate.update(HibernateTemplate.java:638) cn.itcast.dao.CustomerDaoImpl.update(CustomerDaoImpl.java:35) cn.itcast.service.CustomerService.update(CustomerService.java:39) cn.itcast.service.CustomerService$$FastClassBySpringCGLIB$$daf8667d.invoke(<generated>) org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204) org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:720) org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157) org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99) org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281) org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96) org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:655) cn.itcast.service.CustomerService$$EnhancerBySpringCGLIB$$74cc781b.update(<generated>) cn.itcast.action.CustomerAction.update(CustomerAction.java:92) sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) java.lang.reflect.Method.invoke(Method.java:498) ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:870) ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:1293) ognl.ObjectMethodAccessor.callMethod(ObjectMethodAccessor.java:68) com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethodWithDebugInfo(XWorkMethodAccessor.java:117) com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethod(XWorkMethodAccessor.java:108) ognl.OgnlRuntime.callMethod(OgnlRuntime.java:1369) ognl.ASTMethod.getValueBody(ASTMethod.java:90) ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212) ognl.SimpleNode.getValue(SimpleNode.java:258) ognl.Ognl.getValue(Ognl.java:494) ognl.Ognl.getValue(Ognl.java:458) com.opensymphony.xwork2.ognl.OgnlUtil$2.execute(OgnlUtil.java:309) com.opensymphony.xwork2.ognl.OgnlUtil.compileAndExecute(OgnlUtil.java:340) com.opensymphony.xwork2.ognl.OgnlUtil.getValue(OgnlUtil.java:307) com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:423) com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:287) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:250) org.apache.struts2.interceptor.DeprecationInterceptor.intercept(DeprecationInterceptor.java:41) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:167) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265) org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:76) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:191) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:73) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.interceptor.DateTextFieldInterceptor.intercept(DateTextFieldInterceptor.java:125) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:91) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:253) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:139) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:193) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:189) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54) org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:564) org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:81) org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99) root cause org.hibernate.TransientObjectException: The given object has a null identifier: cn.itcast.entity.Customer org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.getUpdateId(DefaultSaveOrUpdateEventListener.java:255) org.hibernate.event.internal.DefaultUpdateEventListener.getUpdateId(DefaultUpdateEventListener.java:53) org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsDetached(DefaultSaveOrUpdateEventListener.java:222) org.hibernate.event.internal.DefaultUpdateEventListener.performSaveOrUpdate(DefaultUpdateEventListener.java:38) org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:73) org.hibernate.internal.SessionImpl.fireUpdate(SessionImpl.java:703) org.hibernate.internal.SessionImpl.update(SessionImpl.java:695) org.hibernate.internal.SessionImpl.update(SessionImpl.java:690) org.springframework.orm.hibernate5.HibernateTemplate$14.doInHibernate(HibernateTemplate.java:647) org.springframework.orm.hibernate5.HibernateTemplate.doExecute(HibernateTemplate.java:341) org.springframework.orm.hibernate5.HibernateTemplate.executeWithNativeSession(HibernateTemplate.java:309) org.springframework.orm.hibernate5.HibernateTemplate.update(HibernateTemplate.java:643) org.springframework.orm.hibernate5.HibernateTemplate.update(HibernateTemplate.java:638) cn.itcast.dao.CustomerDaoImpl.update(CustomerDaoImpl.java:35) cn.itcast.service.CustomerService.update(CustomerService.java:39) cn.itcast.service.CustomerService$$FastClassBySpringCGLIB$$daf8667d.invoke(<generated>) org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204) org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:720) org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157) org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99) org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281) org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96) org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:655) cn.itcast.service.CustomerService$$EnhancerBySpringCGLIB$$74cc781b.update(<generated>) cn.itcast.action.CustomerAction.update(CustomerAction.java:92) sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) java.lang.reflect.Method.invoke(Method.java:498) ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:870) ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:1293) ognl.ObjectMethodAccessor.callMethod(ObjectMethodAccessor.java:68) com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethodWithDebugInfo(XWorkMethodAccessor.java:117) com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethod(XWorkMethodAccessor.java:108) ognl.OgnlRuntime.callMethod(OgnlRuntime.java:1369) ognl.ASTMethod.getValueBody(ASTMethod.java:90) ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212) ognl.SimpleNode.getValue(SimpleNode.java:258) ognl.Ognl.getValue(Ognl.java:494) ognl.Ognl.getValue(Ognl.java:458) com.opensymphony.xwork2.ognl.OgnlUtil$2.execute(OgnlUtil.java:309) com.opensymphony.xwork2.ognl.OgnlUtil.compileAndExecute(OgnlUtil.java:340) com.opensymphony.xwork2.ognl.OgnlUtil.getValue(OgnlUtil.java:307) com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:423) com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:287) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:250) org.apache.struts2.interceptor.DeprecationInterceptor.intercept(DeprecationInterceptor.java:41) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:167) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265) org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:76) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:191) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:73) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.interceptor.DateTextFieldInterceptor.intercept(DateTextFieldInterceptor.java:125) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:91) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:253) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:139) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:193) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:189) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54) org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:564) org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:81) org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99) note The full stack trace of the root cause is available in the Apache Tomcat/8.5.9 logs.
解决办法就是将提交表单中的name属性名改成和类属性名一样。