实体类和数据表的映射异常（XXX is not mapping[ ]）

在使用SSH框架开发过程，使用hibernate框架提供的工具类实现与数据库数据交互，在执行cmd操作时，如果出现以下异常：

org.hibernate.hql.ast.QuerySyntaxException: xxx is not mapped [from xxx] 或者

nested exception is org.hibernate.hql.internal.ast.QuerySyntaxException

详细异常信息

21:08:31,951 ERROR DefaultDispatcherErrorHandler:42 - Exception occurred during processing request: Customer is not mapped [from Customer]; nested exception is org.hibernate.hql.internal.ast.QuerySyntaxException: Customer is not mapped [from Customer]
org.springframework.orm.hibernate5.HibernateQueryException: Customer is not mapped [from Customer]; nested exception is org.hibernate.hql.internal.ast.QuerySyntaxException: Customer is not mapped [from Customer]at org.springframework.orm.hibernate5.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:176)at org.springframework.orm.hibernate5.HibernateTemplate.doExecute(HibernateTemplate.java:344)at org.springframework.orm.hibernate5.HibernateTemplate.executeWithNativeSession(HibernateTemplate.java:309)at org.springframework.orm.hibernate5.HibernateTemplate.find(HibernateTemplate.java:863)at cn.itheima.ssh_exem.dao.impl.CustomerDaoImpl.findAllCustomer(CustomerDaoImpl.java:26)at cn.itheima.ssh_exem.service.impl.CustomerServiceImpl.findAllCustomer(CustomerServiceImpl.java:22)at cn.itheima.ssh_exem.action.CustomerAction.findCustomer(CustomerAction.java:38)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 ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:870)at ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:1293)at ognl.ObjectMethodAccessor.callMethod(ObjectMethodAccessor.java:68)at com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethodWithDebugInfo(XWorkMethodAccessor.java:117)at com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethod(XWorkMethodAccessor.java:108)at ognl.OgnlRuntime.callMethod(OgnlRuntime.java:1369)at ognl.ASTMethod.getValueBody(ASTMethod.java:90)at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212)at ognl.SimpleNode.getValue(SimpleNode.java:258)at ognl.Ognl.getValue(Ognl.java:494)at ognl.Ognl.getValue(Ognl.java:458)at com.opensymphony.xwork2.ognl.OgnlUtil$2.execute(OgnlUtil.java:309)at com.opensymphony.xwork2.ognl.OgnlUtil.compileAndExecute(OgnlUtil.java:340)at com.opensymphony.xwork2.ognl.OgnlUtil.getValue(OgnlUtil.java:307)at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:423)at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:287)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:250)at org.apache.struts2.interceptor.DeprecationInterceptor.intercept(DeprecationInterceptor.java:41)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:167)at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265)at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:76)at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229)at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229)at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:191)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:73)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at org.apache.struts2.interceptor.DateTextFieldInterceptor.intercept(DateTextFieldInterceptor.java:125)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:91)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:253)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171)at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:139)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:193)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:189)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54)at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:564)at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:81)at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)at org.springframework.orm.hibernate5.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:151)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.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:505)at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:436)at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1078)at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:625)at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)at java.util.concurrent.ThreadPoolExecutor$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)