删除数据时，获取ID为空。注意检查请求时候的id能否获取到，或者是请求连接是否有误。

本文链接：https://blog.youkuaiyun.com/c1005351789/article/details/7006874
java.lang.IllegalArgumentException: attempt to create delete event with null entity
	org.hibernate.event.DeleteEvent.<init>(DeleteEvent.java:47)
	org.hibernate.impl.SessionImpl.delete(SessionImpl.java:772)
	org.springframework.orm.hibernate3.HibernateTemplate$25.doInHibernate(HibernateTemplate.java:852)
	org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:419)
	org.springframework.orm.hibernate3.HibernateTemplate.executeWithNativeSession(HibernateTemplate.java:374)
	org.springframework.orm.hibernate3.HibernateTemplate.delete(HibernateTemplate.java:846)
	org.springframework.orm.hibernate3.HibernateTemplate.delete(HibernateTemplate.java:842)
	com.dao.PftypeDAO.delete(PftypeDAO.java:42)
	com.biz.TypeBizImp.deleteType(TypeBizImp.java:32)
	sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	java.lang.reflect.Method.invoke(Method.java:597)
	org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)
	org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)
	org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
	org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)
	org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
	org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:89)
	org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
	org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
	$Proxy1.deleteType(Unknown Source)
	com.action.TypeAction.deleteType(TypeAction.java:87)
	sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	java.lang.reflect.Method.invoke(Method.java:597)
	com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:441)
	com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:280)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:243)
	com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:165)
	com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
	com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:252)
	org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
	com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
	com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:122)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
	com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
	com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
	com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
	com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
	com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:179)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
	org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
	org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:94)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
	org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:235)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
	com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:89)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
	com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:130)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
	org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:267)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
	com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:126)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
	com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:138)
	com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
	com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:165)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
	org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
	com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:179)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
	com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:176)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
	org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)
	org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:488)
	org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
	org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)
	org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:198)
	org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)