SpringMVC的filter怎么使用Autowired依赖注入bean

 

有的时候根据我们业务的需要，我们需要在web项目中定义一个自己的filter,并想在这个filter中使用@Autowired注入bean供我们使用。如果直接使用的话是不行的，需要我们在xml文件中进行配置。下面就根据我的一个项目写一个示例:

步骤一、定义一个ClientSessionFilter，在这个Filter中注入我们想要的bean

public class ClientSessionFilter implements Filter {
    private static Logger log = Logger.getLogger(ClientSessionFilter.class);
    @Autowired
    private RequestData requestData; //我们想要注入的bean
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        ObjectMapper mapper = new ObjectMapper();
        HttpServletRequest httpServletReq = (HttpServletRequest) request;
        String session = httpServletReq.getHeader("S");
        ClientSession cs;
        if(StringUtils.isNotBlank(session)) {
            try {
                cs = mapper.readValue(session, ClientSession.class);
            } catch (Exception e) {
                log.error("Session序列化错误" + e);
                throw new BusinessException(401, "Session序列化错误");
            }
            if(log.isDebugEnabled()) {
                log.debug(cs);
            }
            requestData.setClientSession(cs);
        }
        chain.doFilter(request, response);
    }
    @Override
    public void destroy() {
    }
}

步骤二、在spring的配置文件application.xml中配置我们想要的bean和自定义的filter

<bean id="requestData" scope="request" class="cn.ucmed.common.cache.RequestData">
    <aop:scoped-proxy/> //这个标签可以参考上一遍博客
</bean>

<bean id="clientSessionFilter" class="cn.ucmed.baseline.d2d.filter.ClientSessionFilter" />

步骤三、在web.xml中配置fileter

<filter>
  <filter-name>filterProxy</filter-name>
  <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
  <async-supported>true</async-supported>
  <init-param>
    <param-name>targetBeanName</param-name>
    <param-value>clientSessionFilter</param-value>
  </init-param>
  <init-param>
    <param-name>targetFilterLifecycle</param-name>
    <param-value>true</param-value>
  </init-param>
</filter>
<filter-mapping>
  <filter-name>filterProxy</filter-name>
  <url-pattern>/registeryuyue/*</url-pattern>
</filter-mapping>