Properties in application.properties not getting loaded in Filter class

Question

I am trying to read the value from application.properties in one of the util library Filter we write.

My code is as below.

public class AuthorizationFilter extends GenericFilterBean
{

    @Value ("${application.identifier}")
    private String appId;
    ...
}

However the value appId is not read from application.properties though it is defined. The issue occurs only with Filter classes.

Any pointers on how to fix this?

Answer 1

Like @M.Deinum said , If you let spring-boot manage the life cycle of the filter bean, then you will be able use the @Value annotation :

@Component
@Order(1)
public class CustomFilter implements Filter {
 
@Value ("${application.identifier}")
private String appId;

    @Override
    public void doFilter
      ServletRequest request, 
      ServletResponse response, 
      FilterChain chain) throws IOException, ServletException {
  
        HttpServletRequest req = (HttpServletRequest) request;
        LOG.info(
          "Starting for req : {}", 
          req.getRequestURI());
  
        chain.doFilter(request, response);
        LOG.info(
          "Anything");
    }
 
    // other methods 
}

Keep in mind that if you provide your filter this way , you won't have to register it manually and if you want it to work for a particular url by registering it manually remember to remove the @Component annotation so that spring-boot won't take it up automatically.

Answer 2

Let the spring manage your filter class. You can register in your filter class like below :

@Bean
public FilterRegistrationBean registerFilter() {
    FilterRegistrationBean registration = new FilterRegistrationBean();
    registration.setFilter(this);
    registration.addUrlPatterns("/*");
    return registration;
}