Java 无法将GenericaApplicationContext强制转换为WebApplicationContext:Spring Web流_Java_Spring_Spring Mvc_Classcastexception_Spring Webflow 2

Java 无法将GenericaApplicationContext强制转换为WebApplicationContext:Spring Web流

java spring spring-mvc

Java 无法将GenericaApplicationContext强制转换为WebApplicationContext:Spring Web流,java,spring,spring-mvc,classcastexception,spring-webflow-2,Java,Spring,Spring Mvc,Classcastexception,Spring Webflow 2,我试图在一个也只使用Java注释的Spring环境中，仅使用Java注释来设置SpringWebFlow。然而，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.ex

我试图在一个也只使用Java注释的Spring环境中，仅使用Java注释来设置SpringWebFlow。然而，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)

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;
    }
}

@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;
     }
}

FlowBuilderServices

应该是一个Spring管理的bean，但在您的配置中它只是一个

新的

实例。它喜欢

ApplicationContextAware

和

InitializingBean

，但这只有在Spring管理下才能起作用

解决方案很简单：将

@Bean

放在

getFlowBuilderServices（）

方法上。我认为您还应该将

MvcViewFactoryCreator

作为一个单独的

@Bean

，而不是手动使用它的

setApplicationContext（）

@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;
    }
}

@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;
     }
}