spring - WebApplicationInitializer 被重复调用

Question

我有一个基于 Spring 3.1 的应用程序托管在 Tomcat 7.x(最新版本)下。该应用程序仅使用 Java 配置(无 web.xml，无 Spring XML 配置)。所有单元测试都通过了，包括使用 Spring Java 配置 (@ContextConfiguration) 的单元测试。

问题是当部署应用程序时，WebApplicationInitializer 实现被调用多次。过滤器和监听器的重复注册会导致异常，并且应用程序永远不会启动。

我没想到 WebApplicationInitializer.onStartup() 会被重复调用，如果可能的话我想消除这种行为。如果有人对为什么会发生这种情况以及如何阻止它提出建议，我将不胜感激。

更新 我认为问题出在初始化类本身之外，但这里是为了防止我弄错了...

public class DeploymentDescriptor implements WebApplicationInitializer {

    private static final Logger LOGGER = LoggerFactory.getLogger("org.ghc.web-app-initializer");

    @Override
    public void onStartup (ServletContext servletContext) throws ServletException {
        // This is the programmatic way of declaring filters. This allows you to order
        // Filters. The order of these security filters DOES MATTER!
        FilterRegistration.Dynamic mockSecurityFilter       = servletContext.addFilter ("mockSecurityFilter", "org.ghc.security.MockSecurityFilter");
        mockSecurityFilter.addMappingForUrlPatterns         (EnumSet.of (REQUEST), true, "/*");

        FilterRegistration.Dynamic siteMinderSecurityFilter = servletContext.addFilter ("siteMinderSecurityFilter", "org.ghc.security.SiteMinderSecurityFilter");
        siteMinderSecurityFilter.addMappingForUrlPatterns   (EnumSet.of (REQUEST), true, "/*");

        FilterRegistration.Dynamic userDetailsStoreFilter   = servletContext.addFilter ("userDetailsStoreFilter", "org.ghc.security.UserDetailsStoreFilter");
        userDetailsStoreFilter.addMappingForUrlPatterns     (EnumSet.of (REQUEST), true, "/*");


        // Static resource handling using "default" servlet
        servletContext.getServletRegistration ("default").addMapping ("*.js", "*.css", "*.jpg", "*.gif", "*.png");
        // Map jspf files to jsp servlet
        servletContext.getServletRegistration ("jsp").addMapping ("*.jspf");


        // Spin up the Spring 3.1 class that can scan a package tree for classes
        // annotated with @Configuration. See org.ghc.spring3.ControllerConfiguration for
        // this example.
        final AnnotationConfigWebApplicationContext dispatcherContext = new AnnotationConfigWebApplicationContext ();
        dispatcherContext.setServletContext (servletContext);
        dispatcherContext.register(ScProviderDirectory.class);
        dispatcherContext.refresh ();

        // Spin up the Spring DispatcherServlet (just like before) passing the just built
        // application context. Load it like the regular Servlet that it is!
        final ServletRegistration.Dynamic servlet = servletContext.addServlet ("spring", new DispatcherServlet(dispatcherContext));
        servlet.setLoadOnStartup (1);
        servlet.addMapping ("/");  // Make sure this is NOT "/*"!
    }
}

更新 2 这很奇怪。 Tomcat 日志似乎标识了我的 DeploymentDescriptor 类的两个实例。我确认在我的 .war 文件中只有一个此类实例。我不知道第二个(幻影)实例来自哪里，但至少这解释了为什么类被扫描两次...

logs/localhost.2012-10-09.log:INFO: Spring WebApplicationInitializers detected on classpath: [org.ghc.configuration.DeploymentDescriptor@3b29642c]
logs/localhost.2012-10-09.log:INFO: Spring WebApplicationInitializers detected on classpath: [org.ghc.configuration.DeploymentDescriptor@432c4c7a]

Answer 1

这里的问题是 Maven Overlay 将 crap 一个 Spring xml 配置文件转储到我的应用程序中。无论出于何种原因，这都会导致 WebApplicationInitializer.onStartup() 被调用两次。可能是应用程序上下文和 servlet 上下文的初始化。关闭叠加层，应用程序正在按预期进行初始化。