OpenJPA2.0.1一个疑问

最近在修改一个项目，有个问题困扰了很久一直没时间去解决。这次又在网上找了找，还是没有结果。闲话不多说了，错误代码：

 

<openjpa-2.0.1-r422266:989424 nonfatal user error> org.apache.openjpa.persistence.ArgumentException: Failed to execute query "null". Check the query syntax for correctness. See nested exception for details.
	at org.apache.openjpa.kernel.QueryImpl.execute(QueryImpl.java:870)
	at org.apache.openjpa.kernel.QueryImpl.execute(QueryImpl.java:792)
	at org.apache.openjpa.kernel.DelegatingQuery.execute(DelegatingQuery.java:542)
	at org.apache.openjpa.persistence.QueryImpl.execute(QueryImpl.java:288)
	at org.apache.openjpa.persistence.QueryImpl.getResultList(QueryImpl.java:302)
	at org.apache.openjpa.persistence.QueryImpl.getSingleResult(QueryImpl.java:326)
	at com.strong.module.tjbqxh.service.ht.TJbqxhHTServiceXianShiImpl.getFenYe(TJbqxhHTServiceXianShiImpl.java:64)
	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 org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:309)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
	at $Proxy74.getFenYe(Unknown Source)
	at com.strong.module.tjbqxh.controller.ht.TJbqxhHTControllerXianShi.XianShiLieBiaoJSON(TJbqxhHTControllerXianShi.java:49)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:176)
	at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:426)
	at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:414)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:790)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644)
	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:560)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:306)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:366)
	at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:109)
	at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
	at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:97)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
	at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:100)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
	at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:78)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
	at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
	at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:35)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
	at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:177)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
	at org.springframework.security.web.authentication.ui.DefaultLoginPageGeneratingFilter.doFilter(DefaultLoginPageGeneratingFilter.java:91)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
	at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:187)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
	at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
	at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:79)
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
	at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:167)
	at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:237)
	at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:244)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:244)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:550)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:380)
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:243)
	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:288)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
	at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.ClassCastException: org.apache.openjpa.util.IntId cannot be cast to [Ljava.lang.Object;
	at org.apache.openjpa.datacache.QueryCacheStoreQuery$CachedList.get(QueryCacheStoreQuery.java:505)
	at org.apache.openjpa.lib.rop.ListResultObjectProvider.getResultObject(ListResultObjectProvider.java:55)
	at org.apache.openjpa.kernel.QueryImpl$PackingResultObjectProvider.getResultObject(QueryImpl.java:2073)
	at org.apache.openjpa.kernel.QueryImpl.singleResult(QueryImpl.java:1325)
	at org.apache.openjpa.kernel.QueryImpl.toResult(QueryImpl.java:1237)
	at org.apache.openjpa.kernel.QueryImpl.execute(QueryImpl.java:1005)
	at org.apache.openjpa.kernel.QueryImpl.execute(QueryImpl.java:861)
	... 79 more

 出现原因描述：OpenJPA开启了缓存。如果设备（Sb）有个属性叫设备类型（Sblx）。他两是一对多的关系。单独分页查询设备类型没有问题。如果在添加设备的时候查询所有设备类型，也没有问题。但在去查询设备类型的时候就报上述错误。

挠头苦思半响，去掉缓存。居然就可以了。但是这样缓存用不上了，有点不心甘。最后发现。缓存开启、JPQL语句没有where条件的两个查询会出上述错误，select count(t) from TSblx  t（在分页查询时候要获取总数） 和 select t from TSblx t; 所以我就在查询所有设备类型时候多加个条件就可以了。

获取总数代码：

 

    EntityManager em = tsblxDAO.getEntityManager();
    CriteriaBuilder cb = em.getCriteriaBuilder();

    CriteriaQuery<Long> cq = cb.createQuery(Long.class);
    Root<TSblx> root = cq.from(TSblx.class);
    cq.select(cb.count(root));
    TypedQuery<Long> tq = em.createQuery(cq);
    tq.getSingleResult();

 查询所有代码：

 

    EntityManager em = tsblxDAO.getEntityManager();
    CriteriaBuilder cb = em.getCriteriaBuilder();
    CriteriaQuery<TSblx> cq = cb.createQuery(TSblx.class);
    Root<TSblx> root = cq.from(TSblx.class);
    cq.select(root);
 //在这加个查询条件
    TypedQuery<TSblx> tq = em.createQuery(cq);
    return tq.getResultList();

 

另外可以在操作之前清空缓存：

 

 

    EntityManagerFactory emf = tsbDAO.getEntityManagerFactory();
    OpenJPAEntityManagerFactory oemf = OpenJPAPersistence.cast(emf);
    Cache qcache = oemf.getCache();
    qcache.evictAll();