基于Spring代码的配置 - IllegalArgumentException：需要ServletContext [英] Spring code-based configuration - IllegalArgumentException: A ServletContext is required

问题描述

我在这里找到了一个基于100％代码的弹簧配置的例子：

I have found an example of 100% code-based spring configuration here:

http://docs.spring.io/spring/docs/3.1.x/javadoc-api/org/springframework/web/WebApplicationInitializer.html

内容：

public class MyWebAppInitializer implements WebApplicationInitializer {

@Override
public void onStartup(ServletContext container) {
  // Create the 'root' Spring application context
  AnnotationConfigWebApplicationContext rootContext =
    new AnnotationConfigWebApplicationContext();
  rootContext.register(AppConfig.class);

  // Manage the lifecycle of the root application context
  container.addListener(new ContextLoaderListener(rootContext));

  // Create the dispatcher servlet's Spring application context
  AnnotationConfigWebApplicationContext dispatcherContext =
    new AnnotationConfigWebApplicationContext();
  dispatcherContext.register(DispatcherConfig.class);

  // Register and map the dispatcher servlet
  ServletRegistration.Dynamic dispatcher =
    container.addServlet("dispatcher", new DispatcherServlet(dispatcherContext));
  dispatcher.setLoadOnStartup(1);
  dispatcher.addMapping("/");
}

}

refresh（）注册配置类后。
但是API说 - 必须调用refresh（）才能使上下文完全处理新类。
所以我添加refresh（）每个寄存器语句

In the example above they never called refresh() after registering a configuration class. But API says - that refresh() must be called in order for the context to fully process the new class. So I added refresh() afrer each register statement

rootContext.register(AppConfig.class);
rootContext.refresh();

dispatcherContext.register(DispatcherConfig.class);
dispatcherContext.refresh();

结果：

SEVERE: ContainerBase.addChild: start: 
org.apache.catalina.LifecycleException: Failed to start component    [StandardEngine[Catalina].StandardHost[localhost].StandardContext[]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:726)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:702)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:699)
at org.apache.catalina.startup.HostConfig.manageApp(HostConfig.java:1647)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:300)
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
at org.apache.catalina.mbeans.MBeanFactory.createStandardContext(MBeanFactory.java:465)
at org.apache.catalina.mbeans.MBeanFactory.createStandardContext(MBeanFactory.java:415)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:300)
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
at javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1487)
at javax.management.remote.rmi.RMIConnectionImpl.access$300(RMIConnectionImpl.java:97)
at javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1328)
at javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1420)
at javax.management.remote.rmi.RMIConnectionImpl.invoke(RMIConnectionImpl.java:848)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:322)
at sun.rmi.transport.Transport$1.run(Transport.java:177)
at sun.rmi.transport.Transport$1.run(Transport.java:174)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:173)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:556)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:811)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:670)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:724)
    Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'defaultServletHandlerMapping' defined in class path resource [org/springframework/web/servlet/config/annotation/DelegatingWebMvcConfiguration.class]: Instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public org.springframework.web.servlet.HandlerMapping org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport.defaultServletHandlerMapping()] threw exception; nested exception is java.lang.IllegalArgumentException: A ServletContext is required to configure default servlet handling
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:592)

推荐答案

在这种情况下，这只对于 ApplicationContext 传递给 DispatcherServlet 。 DispatcherServlet 构造函数状态

In your case, this is only important for the ApplicationContext passed to the DispatcherServlet. That DispatcherServlet constructor states

给定的Web应用程序上下文可能尚未刷新。如果
尚未刷新（建议的方法），那么将会出现
：

The given web application context may or may not yet be refreshed. If it has not already been refreshed (the recommended approach), then the following will occur:

• 如果给定的上下文没有父级，则根应用上下文将被设置为父级。


• 如果给定的上下文尚未分配ID，则会为其分配一个


• ServletContext 和 ServletConfig 对象将被委派给应用程序上下文


• postProcessWebApplicationContext 将被调用


• 任何 ApplicationContextInitializers 通过
  指定contextInitializerClasses param或通过
  的setContextInitializers属性将被应用。如果上下文实现 ConfigurableApplicationContext
，将调用

• refresh li>


• If the given context does not already have a parent, the root application context will be set as the parent.
• If the given context has not already been assigned an id, one will be assigned to it
• ServletContext and ServletConfig objects will be delegated to the application context
• postProcessWebApplicationContext will be called
• Any ApplicationContextInitializers specified through the "contextInitializerClasses" init-param or through the setContextInitializers property will be applied.
• refresh() will be called if the context implements ConfigurableApplicationContext

如果上下文已经刷新，上面将不会出现
，假设用户有

因此，对于 DispatcherServlet ，您必须执行以下操作：

So for the DispatcherServlet, you have to do the following

AnnotationConfigWebApplicationContext dispatcherContext = new AnnotationConfigWebApplicationContext();
dispatcherContext.register(DispatcherConfig.class);

// will take care of calling refresh() on the ApplicationContext
ServletRegistration.Dynamic dispatcher = container.addServlet("dispatcher", new DispatcherServlet(dispatcherContext));

这是 DispatcherServlet 配置所必需的，因为由于 @EnableWebMvc （或等效的< mvc：annotation-driven> ）生成的一些bean需要 ServletContext 和/或 ServletConfig 由Servlet容器提供的对象。

This is necessary for the DispatcherServlet configuration because some of the beans generated because of @EnableWebMvc (or the equivalent <mvc:annotation-driven>) require the ServletContext and/or ServletConfig objects which are provided by the Servlet container.

根上下文不应该有这样的依赖，所以它是安全的做

The root context should not have such dependencies so it is safe to do

AnnotationConfigWebApplicationContext rootContext = new AnnotationConfigWebApplicationContext();
rootContext.register(AppConfig.class);
rootContext.refresh();

<通过将 @Configuration 类作为参数传递给它的构造函数。

Note that you could just create the AnnotationConfigWebApplicationContext object by passing the @Configuration classes as arguments to its constructor.

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