我试图在仅使用Java注释的Spring环境中仅使用Java注释来设置Spring Web Flow。但是，当我尝试访问我的流时，我得到以下异常
SEVERE: Servlet.service() for servlet [dispatcher] in context with path [/forms] threw exception [Request processing failed; nested exception is org.springframework.webflow.execution.FlowExecutionException: Exception thrown in state 'referral' of flow 'test-flow'] with root cause
java.lang.ClassCastException: org.springframework.context.support.GenericApplicationContext cannot be cast to org.springframework.web.context.WebApplicationContext
at org.springframework.web.servlet.support.RequestContext.initContext(RequestContext.java:235)
at org.springframework.web.servlet.support.RequestContext.<init>(RequestContext.java:202)
at org.springframework.web.servlet.view.AbstractView.createRequestContext(AbstractView.java:316)
at org.springframework.web.servlet.view.AbstractView.createMergedOutputModel(AbstractView.java:296)
at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:265)
at org.springframework.webflow.mvc.servlet.ServletMvcView.doRender(ServletMvcView.java:55)
at org.springframework.webflow.mvc.view.AbstractMvcView.render(AbstractMvcView.java:196)
at org.springframework.webflow.engine.ViewState.render(ViewState.java:293)
at org.springframework.webflow.engine.ViewState.refresh(ViewState.java:242)
at org.springframework.webflow.engine.ViewState.resume(ViewState.java:220)
at org.springframework.webflow.engine.Flow.resume(Flow.java:537)
at org.springframework.webflow.engine.impl.FlowExecutionImpl.resume(FlowExecutionImpl.java:259)
at org.springframework.webflow.executor.FlowExecutorImpl.resumeExecution(FlowExecutorImpl.java:169)
at org.springframework.webflow.mvc.servlet.FlowHandlerAdapter.handle(FlowHandlerAdapter.java:228)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:938)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:870)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:852)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:957)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:423)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1079)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:620)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2476)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2465)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
我已经将错误的来源跟踪到RequestContext对象的实例化，该对象被传递给视图以便他们访问ApplicationContext（以及其他内容）。由于Spring能够调用我的流，因此我认为由于我的Web Flow文件中某处的配置错误而导致抛出此异常。我已经多次审核过它们，找不到任何看似明显的东西。您可以在下面找到我的Web Flow配置文件：
DispatcherConfig
@Configuration
@ComponentScan(basePackages = "----")
public class DispatcherConfig {
@Autowired
private FlowDefinitionRegistry flowDefinitionRegistry;
@Autowired
private FlowExecutor flowExecutor;
@Autowired
private AnnotationConfigWebApplicationContext appContext;
@Bean
public FlowHandlerAdapter flowHandlerAdapter()
{
FlowHandlerAdapter flowHandlerAdapter = new FlowHandlerAdapter();
flowHandlerAdapter.setFlowExecutor(flowExecutor);
return flowHandlerAdapter;
}
@Bean
public FlowHandlerMapping flowHandlerMapping()
{
FlowHandlerMapping mapping = new FlowHandlerMapping();
mapping.setFlowRegistry(flowDefinitionRegistry);
mapping.setApplicationContext(appContext);
mapping.setOrder(-1);
return mapping;
}
}
WebFlowConfig
@Configuration
public class WebFlowConfig extends AbstractFlowConfiguration {
@Autowired
private List<ViewResolver> viewResolvers;
@Autowired
private ConversionService conversionService;
@Autowired
private AnnotationConfigWebApplicationContext appContext;
@Bean
public FlowDefinitionRegistry flowRegistry()
{
return getFlowDefinitionRegistryBuilder()
.setBasePath("/WEB-INF/flows")
.addFlowLocationPattern("/**/*-flow.xml")
.setFlowBuilderServices(getFlowBuilderServices())
.build();
}
@Bean
public FlowExecutor flowExecutor()
{
return getFlowExecutorBuilder(flowRegistry()).build();
}
public ExpressionParser getExpressionParser()
{
SpelExpressionParser spelExpressionParser = new SpelExpressionParser();
return new WebFlowSpringELExpressionParser(spelExpressionParser);
}
public FlowBuilderServices getFlowBuilderServices()
{
MvcViewFactoryCreator creator = new MvcViewFactoryCreator();
creator.setViewResolvers(viewResolvers);
creator.setApplicationContext(appContext);
creator.setUseSpringBeanBinding(true);
FlowBuilderServices services = new FlowBuilderServices();
services.setViewFactoryCreator(creator);
services.setConversionService(conversionService);
services.setExpressionParser(getExpressionParser());
return services;
}
}
WebMvcConfig
@EnableWebMvc
@Configuration
public class WebMvcConfig extends WebMvcConfigurerAdapter {
@Bean
public UrlBasedViewResolver velocityViewResolver()
{
UrlBasedViewResolver resolver = new VelocityViewResolver();
resolver.setSuffix(".vm");
resolver.setViewClass(VelocityView.class);
return resolver;
}
@Bean
public VelocityConfigurer velocityConfig()
{
VelocityConfigurer velocityConfigurer = new VelocityConfigurer();
velocityConfigurer.setResourceLoaderPath("/templates/views/");
return velocityConfigurer;
}
@Bean
public List<ViewResolver> viewResolvers()
{
List<ViewResolver> resolvers = new ArrayList<>();
resolvers.add(velocityViewResolver());
return resolvers;
}
}
我使用的视图技术是Velocity。 Spring Webflow版本2.4.1.RELEASE，Spring版本4.1.2.RELEASE，Java 1.8.0_45，Tomcat 7.0.62。
可能导致此异常的任何想法？
更新：已修复
感谢Roman提供答案。我制作了FlowBuilderServices和MvcViewFactoryCreator @Bean，这就摆脱了ClassCastException。但是，我的配置仍然存在一些问题。直到@Autowired之后，我的List<ViewResolver> viewResolvers MvcViewFactoryCreator才被实例化。因此，我必须创建一个为ViewResolver创建MvcViewFactoryCreator列表的方法。我正在研究如何使创作顺序正确，但现在这种方法有效。以下是我为使Web Flow正常运行而必须进行的更改
WebFlowConfig
@Configuration
public class WebFlowConfig extends AbstractFlowConfiguration {
@Autowired
===
-private List<ViewResolver> viewResolvers;
====
+private UrlBasedViewResolver viewResolver
===
...
@Autowired
===
-private AnnotationConfigWebApplicationContext appContext;
===
+private MvcViewFactoryCreator mvcViewFactoryCreator;
===
...
+public List<ViewResolver> getViewResolvers()
+{
+ List<ViewResolver> resolvers = new ArrayList<>();
+ resolvers.add(viewResolver);
+
+ return resolvers;
+}
...
+@Bean
+public MvcViewFactoryCreator mvcViewFactoryCreator()
+{
+ MvcViewFactoryCreator creator = new MvcViewFactoryCreator();
+ creator.setViewResolvers(getViewResolvers());
+ creator.setUseSpringBeanBinding(true);
+ return creator;
+}
@Bean
public FlowBuilderServices flowBuilderServices()
{
===
-MvcViewFactoryCreator creator = new MvcViewFactoryCreator();
-creator.setViewResolvers(viewResolvers);
-creator.setApplicationContext(appContext);
-creator.setUseSpringBeanBinding(true);
===
FlowBuilderServices services = new FlowBuilderServices();
===
-services.setViewFactoryCreator(creator);
===
+services.setViewFactoryCreator(mvcViewFactoryCreator);
===
services.setConversionService(conversionService);
services.setExpressionParser(getExpressionParser());
return services;
}
}
答案 0 :(得分：0)
FlowBuilderServices是一个Spring管理的bean，但在你的配置中它只是一个new实例。它喜欢ApplicationContextAware和InitializingBean，但只有在Spring管理下才会有效。
解决方案很简单：将@Bean放在getFlowBuilderServices()方法上。我认为您还应该MvcViewFactoryCreator单独@Bean而不要手动使用setApplicationContext()。