在DelegatingFilterProxy上使用Spring和@Autowired [英] Spring and @Autowired on a DelegatingFilterProxy

问题描述

我正在尝试将Spring bean注入到过滤器中，但无法使其正常工作.

I'm trying to inject a spring bean into a filter, but can't make it work.

注入的bean始终为"null".我成功在Controllers和HandlerInterceptors中自动装配了相同的bean，因此已正确注释.

The bean injected is always "null". I succeed autowiring this same bean in Controllers and HandlerInterceptors so it's correctly annotated.

过滤器类位于其余Controllers的相同基本程序包中.

The filter class is under the same base-package of the rest of Controllers.

这是我的web.xml的相关部分

This is the relevant part of my web.xml

  <filter>
    <filter-name>CheckSession</filter-name>
    <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>CheckSession</filter-name>
    <url-pattern>/panel/*</url-pattern>
  </filter-mapping>

这是过滤器的代码

@Component 
public class CheckSession extends OncePerRequestFilter implements Filter {

    @Autowired private Usuario usuario;

    @Override
    protected void doFilterInternal(
        HttpServletRequest request,
        HttpServletResponse response, FilterChain chain)
    throws ServletException, IOException {

        //  always null
        System.out.println("autowired " + usuario);
        chain.doFilter(request,  response);
    }
}

过滤器在每个请求上触发.

The filter is triggering on every request.

这些是"Usuario" bean中的注释

These are the annotations in the "Usuario" bean

@Component
@Scope(value="session", proxyMode=ScopedProxyMode.TARGET_CLASS)
public class Usuario implements java.io.Serializable { ... }

我想念什么?谢谢！

推荐答案

尝试为您的CheckSession bean明确定义名称，看看是否有帮助...像这样:

Try to explicitly define the name for your CheckSession bean and see if that helps... Like this:

@Component("CheckSession")
public class CheckSession extends OncePerRequestFilter implements Filter {
    @Autowired private Usuario usuario;

    @Override
    protected void doFilterInternal(HttpServletRequest request,
            HttpServletResponse response, FilterChain chain)
            throws ServletException, IOException {

        //  always null
        System.out.println("autowired " + usuario);
        chain.doFilter(request,  response);
    }
}

关键部分是这样:@Component("CheckSession")

The key part is this: @Component("CheckSession")

为了使事情更漂亮和更容易处理，我将 camelCase 的名称并将其重命名为"checkSession"(取消首字母大写).

And to make things prettier and easier to deal with down the road, I would camelCase the name and rename it to "checkSession" everywhere (de-capitalize first letter).

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