javaEE EJB 同时调用stateful sessionbean里面的两个方法

Question

我同时调用了stateful sessionbean里面的两个方法。报了一下错误，难道stateful sessionbean里面的不能并行被调用？这是为什么呢？信息: EJB5018: 在 [BatchProcessControllerBean] 上调用 EJB 时抛出异常
信息: javax.ejb.ConcurrentAccessException: SessionBean is executing another request. [session-key: a90c06700a81f-ffffffffba18a467-0]
at com.sun.ejb.containers.StatefulSessionContainer.handleConcurrentInvocation(StatefulSessionContainer.java:2624)
at com.sun.ejb.containers.StatefulSessionContainer._getContext(StatefulSessionContainer.java:2462)
at com.sun.ejb.containers.BaseContainer.getContext(BaseContainer.java:1709)
at com.sun.ejb.containers.BaseContainer.preInvoke(BaseContainer.java:1238)
at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:195)
at com.sun.ejb.containers.EJBLocalObjectInvocationHandlerDelegate.invoke(EJBLocalObjectInvocationHandlerDelegate.java:127)
at $Proxy156.getCombinationDegree(Unknown Source)
at pagecode.BatchProcess2.getCombinationDegree(BatchProcess2.java:462)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at javax.el.BeanELResolver.getValue(BeanELResolver.java:293)
at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:175)
at com.sun.faces.el.FacesCompositeELResolver.getValue(FacesCompositeELResolver.java:72)
at com.sun.el.parser.AstValue.getValue(AstValue.java:138)
at com.sun.el.parser.AstDiv.getValue(AstDiv.java:55)
at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:206)
at javax.faces.component.UICommand.getValue(UICommand.java:239)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at javax.faces.component.UIComponentBase$AttributesMap.get(UIComponentBase.java:1585)
at org.richfaces.component.UIProgressBar.broadcast(UIProgressBar.java:133)
at org.ajax4jsf.component.AjaxViewRoot.processEvents(AjaxViewRoot.java:321)
at org.ajax4jsf.component.AjaxViewRoot.broadcastAjaxEvents(AjaxViewRoot.java:340)
at org.ajax4jsf.application.AjaxViewHandler.processAjaxEvents(AjaxViewHandler.java:216)
at org.ajax4jsf.application.AjaxViewHandler.renderView(AjaxViewHandler.java:169)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:110)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:100)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:266)
at org.apache.catalina.core.ApplicationFilterChain.servletService(ApplicationFilterChain.java:427)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:333)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214)
at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:178)
at org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290)
at org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:368)
at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:495)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:246)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214)
at com.digi.cda.uidesign.filter.UrlFilter.doFilter(UrlFilter.java:38)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:246)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:313)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:287)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:218)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:648)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:593)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:94)
at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:98)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:222)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:648)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:593)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:587)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:1093)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:166)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:648)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:593)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:587)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:1093)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:291)
at com.sun.enterprise.web.connector.grizzly.DefaultProcessorTask.invokeAdapter(DefaultProcessorTask.java:666)
at com.sun.enterprise.web.connector.grizzly.DefaultProcessorTask.doProcess(DefaultProcessorTask.java:597)
at com.sun.enterprise.web.connector.grizzly.DefaultProcessorTask.process(DefaultProcessorTask.java:872)
at com.sun.enterprise.web.connector.grizzly.DefaultReadTask.executeProcessorTask(DefaultReadTask.java:341)
at com.sun.enterprise.web.connector.grizzly.DefaultReadTask.doTask(DefaultReadTask.java:263)
at com.sun.enterprise.web.connector.grizzly.DefaultReadTask.doTask(DefaultReadTask.java:214)
at com.sun.enterprise.web.portunif.PortUnificationPipeline$PUTask.doTask(PortUnificationPipeline.java:382)
at com.sun.enterprise.web.connector.grizzly.TaskBase.run(TaskBase.java:264)
at com.sun.enterprise.web.connector.grizzly.ssl.SSLWorkerThread.run(SSLWorkerThread.java:106)

Answer 1

我同时调用了stateful sessionbean里面的两个方法  
是你写错了吧，，，同时调用？？不可能的事情啊，，是一条一条执行的，，是不是你环境配置错了，

Answer 2

SessionBean is executing another request.你相同时调用 但是它不能同时调用 所以就报错了

Answer 3

每个stateful session bean 在bean实例的生命周期内都只服务于一个客户端；他就像是客户端的代理。不同于stateless session bean ，stateful session bean 的实例不会再不同的EJBObject间进行切换，也不会被置于实例池内。一旦stateful session bean被实例化，并被指派给了某个EJB object,它的整个生命周期内只会关联于该EJBobject。stateful session bean维护着会话状态，也就是说：bean class 的实例变量可以在不同的方法调用间维护特定于某个客户端的数据。这使得方法间的彼此依赖成为可能；如果某个方法调用修改了bean的状态，其后的方法调用也将受到影响。正因为如此，来自客户端的每次方法调用都必须由同一个实例来处理，从而，两次方法调用之间的实力状态变化是可预期的。相反，statelsess session bean并不再方法调用间维护于客户端相关的数据，因而任何实例都可以用来处理来自任何客户端的任何方法调用请求。