Spring injection in Filter implementation mapped in web.xml

Question

web.xml:

    myFilter
    com.mypackage.MyFilter


         


        

Answer 1

Since Filter is not a spring bean(it is a web component) the injections won't work inside them. Springs wont inject inside web component.

use a DelegatingFilterProxy, this is a filter implementation that takes a springbean name as init param and delegates the filter request to that bean.

<filter>
  <filter-name>myFilter</filter-name>
  <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
  <init-param>
    <param-name>targetBeanName</param-name>
    <param-value>myFilterBean</param-value>
  </init-param>
</filter>

<filter-mapping>
  <filter-name>myFilter</filter-name>
  <url-pattern>/myFilterPattern/*</url-pattern>
</filter-mapping>

And create a Bean with name myFilterBean in your spring context.

public class MyFilter extends GenericFilterBean {

    @Autowired
    InjectedBean someInjectedBean;
 
    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
      FilterChain chain) throws IOException, ServletException {
        chain.doFilter(request, response);
    }
}