我需要在实现 InitializingBean 的类中自动装配 ServletContextResource

Question

我需要在实现InitializingBean的类中获取ServletContextResource，这怎么可能？我尝试使用以下代码，但它得到了该代码的期望。

代码：

public class InitBean implements InitializingBean {
    @Autowired private ServletContextResource context;

    @Override
    public void afterPropertiesSet() throws Exception {
        // load file from WEB-INF folder here
    }

}

dispatcher-servlet.xml：

<!-- InitBean -->
<bean id="initBean" class="InitBean">
<constructor-arg>
    <value>/WEB-INF/init.properties</value> 
</constructor-arg>

例外：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'initBean': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private org.springframework.web.context.support.ServletContextResource InitBean.context; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No matching bean of type [org.springframework.web.context.support.ServletContextResource] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:286)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1064)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:517)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:291)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:288)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.context.support.AbstractApplicationContext.initMessageSource(AbstractApplicationContext.java:755)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:413)
    at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:276)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:197)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:47)
    at org.mortbay.jetty.handler.ContextHandler.startContext(ContextHandler.java:548)
    at org.mortbay.jetty.servlet.Context.startContext(Context.java:136)
    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:185)
    at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:149)
    at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:219)
    at com.google.appengine.tools.development.DevAppServerMain$StartAction.apply(DevAppServerMain.java:164)
    at com.google.appengine.tools.util.Parser$ParseResult.applyArgs(Parser.java:48)
    at com.google.appengine.tools.development.DevAppServerMain.<init>(DevAppServerMain.java:113)
    at com.google.appengine.tools.development.DevAppServerMain.main(DevAppServerMain.java:89)

Answer 1

我认为您错误使用或误解了@Autowired。

@Autowired 意味着您告诉 Spring 在您的上下文中查找 ServletContextResource 类型的 bean（dispatcher-servlet.xml 文件或任何其他文件）您正在导入的上下文文件），并将其连接到 InitBean 实例中。

从错误消息来看，上下文中没有任何 ServletContextResource beans，因此失败。

您确定要自动装配这样的类型吗？相反，您可以简单地 将 Resource 注入到类中，并让 Spring 上下文解析诸如文件在磁盘上的位置等问题。

听起来您正在这条路径上，但我确实这样做不明白为什么您会尝试使用文件路径的constructor-arg配置bean，然后使用@Autowired。