Guice：在ServletModule中注入攔截器

我想通過由Guice創建的Vaadin應用程序實例注入攔截器。我已經按照在Vaadin Wiki和在Guice Wiki上攔截DI的documenation爲Vaadin - 吉斯一體化的文檔：Guice：在ServletModule中注入攔截器

public class RecruitmentServletConfig extends GuiceServletContextListener { 

    @Override 
    protected Injector getInjector() { 

     ServletModule servletModule = new ServletModule() { 

      @Override 
      protected void configureServlets() { 
       ... 
       bind(Application.class).to(RecruitmentApplication.class).in(ServletScopes.SESSION); 
       SecurityGuard securityGuard = new SecurityGuard(); 
       requestInjection(securityGuard); 
       bindInterceptor(Matchers.subclassesOf(CustomComponent.class), Matchers.annotatedWith(AllowedRoles.class), securityGuard); 
      } 
     }; 
     return Guice.createInjector(servletModule); 
    } 
}

的保全攔截：

public class SecurityGuard implements MethodInterceptor { 
    @Inject private Application application; 

    public Object invoke(MethodInvocation invocation) throws Throwable { 
     AllowedRoles allowedRoles = invocation.getMethod().getAnnotation(AllowedRoles.class); 
     if (((User) application.getUser()).hasRole(allowedRoles.value())) { 
      return invocation.proceed(); 
     } else { 
      return null; 
     } 
}

不過，我得到一個OutOfScopeException在服務器啓動時：

SEVERE: Exception sending context initialized event to listener instance of class de.embl.eicat.recruit.ioc.RecruitmentServletConfig 
com.google.inject.CreationException: Guice creation errors: 
1) Error in custom provider, com.google.inject.OutOfScopeException: Cannot access scoped object. Either we are not currently inside an HTTP Servlet request, or you may have forgotten to apply com.google.inject.servlet.GuiceFilter as a servlet filter for this request. 
at recruit.ioc.RecruitmentServletConfig$1.configureServlets(RecruitmentServletConfig.java:86)

來源

2012-01-03 Nial Darbey

注：應用實例需要對方法被調用在每個新用戶會話（因此。在（ServletScopes.SESSION）然而，該配置（）/ configureServlets（）被創建服務器在創建任何用戶會話之前啓動，我想解釋一下OutOfScopeException。這是真的，應該在哪裏調用requestInjection（securityGuard）？ – 2012-01-03 14:12:11

如果包裝您的Application在Provider？上Application.class範圍

public class SecurityGuard implements MethodInterceptor { 
    @Inject private Provider<Application> application; 

    public Object invoke(MethodInvocation invocation) throws Throwable { 
     AllowedRoles allowedRoles = invocation.getMethod().getAnnotation(AllowedRoles.class); 
     if (((User) application.get().getUser()).hasRole(allowedRoles.value())) { 
      return invocation.proceed(); 
     } else { 
      return null; 
     } 
}

來源

2012-01-03 18:22:22 eiden

是的，這很好，Eiden！非常感謝！ – 2012-01-04 09:13:58

這是正確的解決方案。一個提供者而不是直接引用，Guice將每次調用提供者*應用程序需要時，而不是試圖在前面完成。假設提供者將在* vaadin會話回調期間被調用*，它將成功地通過拉動應用程序來自會話範圍，其中已經設置在堆棧上。 – 2012-01-05 14:39:59

Guice：在ServletModule中注入攔截器

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