Dialect does not support identity key generation

转载自：http://dong717.iteye.com/blog/696195

在使用struts2的json部分是遇到这样的一个异常如下：



org.hibernate.MappingException: Dialect does not support identity key generation
org.hibernate.dialect.Dialect.getIdentitySelectString(Dialect.java:598)
org.hibernate.dialect.Dialect.getIdentitySelectString(Dialect.java:587)
org.hibernate.persister.entity.AbstractEntityPersister.getIdentitySelectString(AbstractEntityPersister.java:2334)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.apache.struts2.json.JSONWriter.bean(JSONWriter.java:226)
org.apache.struts2.json.JSONWriter.processCustom(JSONWriter.java:178)
org.apache.struts2.json.JSONWriter.process(JSONWriter.java:168)
org.apache.struts2.json.JSONWriter.value(JSONWriter.java:134)
org.apache.struts2.json.JSONWriter.map(JSONWriter.java:447)
org.apache.struts2.json.JSONWriter.process(JSONWriter.java:154)
org.apache.struts2.json.JSONWriter.value(JSONWriter.java:134)
org.apache.struts2.json.JSONWriter.add(JSONWriter.java:401)
org.apache.struts2.json.JSONWriter.bean(JSONWriter.java:231)
org.apache.struts2.json.JSONWriter.processCustom(JSONWriter.java:178)
org.apache.struts2.json.JSONWriter.process(JSONWriter.java:168)
org.apache.struts2.json.JSONWriter.value(JSONWriter.java:134)
org.apache.struts2.json.JSONWriter.add(JSONWriter.java:401)
org.apache.struts2.json.JSONWriter.bean(JSONWriter.java:231)
org.apache.struts2.json.JSONWriter.processCustom(JSONWriter.java:178)
org.apache.struts2.json.JSONWriter.process(JSONWriter.java:168)
org.apache.struts2.json.JSONWriter.value(JSONWriter.java:134)
org.apache.struts2.json.JSONWriter.add(JSONWriter.java:401)
org.apache.struts2.json.JSONWriter.bean(JSONWriter.java:231)
org.apache.struts2.json.JSONWriter.processCustom(JSONWriter.java:178)
org.apache.struts2.json.JSONWriter.process(JSONWriter.java:168)
org.apache.struts2.json.JSONWriter.value(JSONWriter.java:134)
org.apache.struts2.json.JSONWriter.add(JSONWriter.java:401)
org.apache.struts2.json.JSONWriter.bean(JSONWriter.java:231)
org.apache.struts2.json.JSONWriter.processCustom(JSONWriter.java:178)
org.apache.struts2.json.JSONWriter.process(JSONWriter.java:168)
org.apache.struts2.json.JSONWriter.value(JSONWriter.java:134)
org.apache.struts2.json.JSONWriter.add(JSONWriter.java:401)
org.apache.struts2.json.JSONWriter.bean(JSONWriter.java:231)
org.apache.struts2.json.JSONWriter.processCustom(JSONWriter.java:178)
org.apache.struts2.json.JSONWriter.process(JSONWriter.java:168)
org.apache.struts2.json.JSONWriter.value(JSONWriter.java:134)
org.apache.struts2.json.JSONWriter.write(JSONWriter.java:102)
org.apache.struts2.json.JSONUtil.serialize(JSONUtil.java:107)
org.apache.struts2.json.JSONResult.createJSONString(JSONResult.java:203)
org.apache.struts2.json.JSONResult.execute(JSONResult.java:177)
com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:369)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:273)
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.
4000
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)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:423)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1079)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:625)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)
java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Unknown Source)解决办法：

这个问题极有可能是由于使用了googlecode的jsonplugin，json是用来实例化bean的；如果action中引用了service，则它也会去试图实例化，这样出错了。方法：可以将service的get方法去掉；或者在其get方法上面加：@JSON(serialize = false)
 

亲测好用！