我尝试使用Google App Engine以下Jaxb2Marshaller代码：
@Entity
@XmlRootElement
public class Incident {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Key incidentId;
我尝试将@XmlJavaTypeAdapter注释与我的特定适配器一起使用，或者@XMLTransiet只是跳过此字段，但我仍然收到以下错误消息。我该如何解决这个问题？
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'appView' defined in ServletContext resource [/WEB-INF/spring/appServlet/servlet-context.xml]: Cannot resolve reference to bean 'jaxbMarshaller' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jaxbMarshaller' defined in ServletContext resource [/WEB-INF/spring/appServlet/servlet-context.xml]: Invocation of init method failed; nested exception is java.lang.NoClassDefFoundError: Lcom/google/appengine/api/datastore/Key;
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:328)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:106)
at org.springframework.beans.factory.support.ConstructorResolver.resolveConstructorArguments(ConstructorResolver.java:630)
at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:148)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1035)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:939)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:485)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:585)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:913)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:464)
at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:631)
at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:588)
at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:645)
at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:508)
at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:449)
at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:133)
at javax.servlet.GenericServlet.init(GenericServlet.java:212)
at org.mortbay.jetty.servlet.ServletHolder.initServlet(ServletHolder.java:440)
at org.mortbay.jetty.servlet.ServletHolder.doStart(ServletHolder.java:263)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
at org.mortbay.jetty.servlet.ServletHandler.initialize(ServletHandler.java:685)
at org.mortbay.jetty.servlet.Context.startContext(Context.java:140)
at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1250)
at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:517)
at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:467)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)
at org.mortbay.jetty.Server.doStart(Server.java:224)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
at com.google.appengine.tools.development.JettyContainerService.startContainer(JettyContainerService.java:197)
at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:241)
at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:148)
at com.google.appengine.tools.development.DevAppServerMain$StartAction.apply(DevAppServerMain.java:259)
at com.google.appengine.tools.util.Parser$ParseResult.applyArgs(Parser.java:48)
at com.google.appengine.tools.development.DevAppServerMain.<init>(DevAppServerMain.java:162)
at com.google.appengine.tools.development.DevAppServerMain.main(DevAppServerMain.java:138)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jaxbMarshaller' defined in ServletContext resource [/WEB-INF/spring/appServlet/servlet-context.xml]: Invocation of init method failed; nested exception is java.lang.NoClassDefFoundError: Lcom/google/appengine/api/datastore/Key;
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1455)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:322)
... 42 more
Caused by: java.lang.NoClassDefFoundError: Lcom/google/appengine/api/datastore/Key;
at java.lang.Class.getDeclaredFields0(Native Method)
at java.lang.Class.privateGetDeclaredFields(Class.java:2291)
at java.lang.Class.getDeclaredFields(Class.java:1743)
at com.sun.xml.internal.bind.v2.model.nav.ReflectionNavigator.getDeclaredFields(ReflectionNavigator.java:238)
at com.sun.xml.internal.bind.v2.model.nav.ReflectionNavigator.getDeclaredFields(ReflectionNavigator.java:47)
at com.sun.xml.internal.bind.v2.model.impl.ClassInfoImpl.findFieldProperties(ClassInfoImpl.java:359)
at com.sun.xml.internal.bind.v2.model.impl.ClassInfoImpl.getProperties(ClassInfoImpl.java:290)
at com.sun.xml.internal.bind.v2.model.impl.RuntimeClassInfoImpl.getProperties(RuntimeClassInfoImpl.java:165)
at com.sun.xml.internal.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:232)
at com.sun.xml.internal.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:89)
at com.sun.xml.internal.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:70)
at com.sun.xml.internal.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:198)
at com.sun.xml.internal.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:84)
at com.sun.xml.internal.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:70)
at com.sun.xml.internal.bind.v2.model.impl.ModelBuilder.getTypeInfo(ModelBuilder.java:304)
at com.sun.xml.internal.bind.v2.model.impl.TypeRefImpl.calcRef(TypeRefImpl.java:81)
at com.sun.xml.internal.bind.v2.model.impl.TypeRefImpl.getTarget(TypeRefImpl.java:58)
at com.sun.xml.internal.bind.v2.model.impl.RuntimeTypeRefImpl.getTarget(RuntimeTypeRefImpl.java:47)