将Filter bean添加到ServletContext

Question

I am using Java configuration and know I can add a custom filter like this:

@Override
public void onStartup(final ServletContext servletContext) throws ServletException {
    super.onStartup(servletContext);
    DelegatingFilterProxy filter = new DelegatingFilterProxy("springSecurityFilterChain");
    filter.setServletContext(servletContext);
    filter.setContextAttribute("org.springframework.web.servlet.FrameworkServlet.CONTEXT.dispatcher");
    servletContext.addFilter("corsFilter", CorsFilter.class).addMappingForUrlPatterns(null, false, "/*");
    servletContext.addFilter("springSecurityFilterChain", filter).addMappingForUrlPatterns(null, true, "/*");
}

This works fine, but feels like I am hacking around the edges of Spring.

What I would like to do is add my CORS filter to the DelegationFilterProxy.

In my root config I added:

@Bean
@Order(Ordered.HIGHEST_PRECEDENCE)
public Filter CorsFilter() {
    return new CorsFilter();
}

and removed the adding of the custom filter in onStartup. Now it does not work at all.

How do I add a bean to my filter chain and make sure it is called first?

Answer 1

You can add it same way as you are adding springSecurityFilteChain in your onStartUp() method like...

@Override
public void onStartup(final ServletContext servletContext) throws ServletException {
    super.onStartup(servletContext);
    DelegatingFilterProxy filter1 = new DelegatingFilterProxy("springSecurityFilterChain");
    filter1.setServletContext(servletContext);
    filter1.setContextAttribute("org.springframework.web.servlet.FrameworkServlet.CONTEXT.dispatcher");
    DelegatingFilterProxy filter2 = new DelegatingFilterProxy("corsFilter");
    servletContext.addFilter("springSecurityFilterChain", filter1).addMappingForUrlPatterns(null, true, "/*");
    servletContext.addFilter("corsFilter",filter2).addMappingForUrlPatterns(null, false, "/*");
}

Answer 2

To simply globally enable the CORS filter using Java config, try this: https://spring.io/blog/2015/06/08/cors-support-in-spring-framework#javaconfig

@Configuration
@EnableWebMvc
public class WebConfig extends WebMvcConfigurerAdapter {

    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**");
    }
}