在Gwt的请求工厂中,什么是ReportableException:请求的类型不是default-instantiable

Question

今天我们开始在生产中遇到这个未知错误

2012 02 06 08:19:39,270 ERROR GWTSpringRequestFactoryServlet$CustomExceptionHandler:34 – Server error
com.google.web.bindery.requestfactory.server.ReportableException: The requested type is not default-instantiable
at com.google.web.bindery.requestfactory.server.ServiceLayerDecorator.report(ServiceLayerDecorator.java:255)
at com.google.web.bindery.requestfactory.server.ReflectiveServiceLayer.createDomainObject(ReflectiveServiceLayer.java:94)
at com.google.web.bindery.requestfactory.server.ServiceLayerDecorator.createDomainObject(ServiceLayerDecorator.java:51)
at com.google.web.bindery.requestfactory.server.LocatorServiceLayer.createDomainObject(LocatorServiceLayer.java:41)
at com.google.web.bindery.requestfactory.server.ServiceLayerDecorator.createDomainObject(ServiceLayerDecorator.java:51)
at com.google.web.bindery.requestfactory.server.RequestState.getBeansForIds(RequestState.java:238)
at com.google.web.bindery.requestfactory.server.RequestState.getBeansForPayload(RequestState.java:147)
at com.google.web.bindery.requestfactory.server.SimpleRequestProcessor.processOperationMessages(SimpleRequestProcessor.java:501)
at com.google.web.bindery.requestfactory.server.SimpleRequestProcessor.process(SimpleRequestProcessor.java:210)
at com.google.web.bindery.requestfactory.server.SimpleRequestProcessor.process(SimpleRequestProcessor.java:127)
at com.google.web.bindery.requestfactory.server.RequestFactoryServlet.doPost(RequestFactoryServlet.java:133)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:368)
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$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:97)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:100)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:78)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:35)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:177)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
at org.springframework.security.web.authentication.ui.DefaultLoginPageGeneratingFilter.doFilter(DefaultLoginPageGeneratingFilter.java:91)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:187)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:79)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:380)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:169)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:237)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:291)
at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:190)
at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:291)
at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:776)
at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:705)
at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:898)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:690)
at java.lang.Thread.run(Thread.java:662)

我们正在使用GWT 2.4,不确定我们在部署上运行的是什么JRE.

我发现这个错误的唯一结果是实际的源代码:

http://code.google.com/p/google-web-toolkit/source/browse/trunk/user/src/com/google/gwt/requestfactory/server/ReflectiveServiceLayer.java?r=9271

调查错误周围的源代码,我们发现第74行的createDomainObject()表示它尝试为某个对象启动构造函数但是失败,因为NoSuchMethodException引发(第82行)然后调用报告这个输出的方法.可能是改变了类/ jar文件的东西.

这里的问题是它不是确定性的,有时它可以工作而有时它失败,运行相同的代码(由客户端的数据网格调用启动).

Answer 1

问题出在我们使用的代理之一DoubleRangeProxy上.这是Apache的DoubleRange类的代理.

该类没有默认构造函数,我们在编译时就被警告过:

/home/gal/gwtapp/proxy/DoubleRangeProxy.java:18: warning: The domain type DoubleRange has no default constructor. Calling RequestContext.create(DoubleRangeProxy.class) will cause a server error.

所以我们用自己的类替换了类,并添加了一个默认的构造函数.

本课程一如既往地阅读(并且不要忽略)编译时警告.