How do I configure cache-control for webjars in spring boot

Question

I've seen a couple of existing answers but when I add the following all webjars start returning 404s. How can I configure cache control for all of my webjars?

@Configuration
public class HttpCacheControlConfig extends WebMvcConfigurerAdapter {


    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/webjars/**").setCachePeriod( 3600 * 24 );
    }
}

Answer 1

You haven't configured any resource locations for the handler. You need something like this:

registry.addResourceHandler("/webjars/**")
        .addResourceLocations("classpath:/META-INF/resources/webjars/")
        .setCachePeriod(3600 * 24);

Alternatively, if you're happy for all of your static resources to have the same cache period then you don't need a WebMvcConfigurerAdapter as you can just configure it with a property in application.properties:

spring.resources.cache-period = 86400