如何在 Spring Boot 2 中定义默认处理程序

Question

How can I define a default handler, or controller action, that will be invoked when no other handler is found for a given URL?

I tried by using a catch-all pattern /** (syntax is Kotlin):

@Controller
class DefaultController {

    @RequestMapping("/**")
    fun default(...) {
        ...
    }
}

But this gets matched with higher precedence that Spring's own handlers, for example the static file path configured in spring.mvc.static-path-pattern is no longer available. I need my default handler to have the lowest precedence.

Answer 1

You would have to add your implementation of HandlerMapping and add it to list of handlers. You need to specify the order of handlers taking care of request as well:

@Bean
public SimpleUrlHandlerMapping simpleUrlHandlerMapping() {
    SimpleUrlHandlerMapping simpleUrlHandlerMapping
      = new SimpleUrlHandlerMapping();
    Map<String, Object> urlMap = new HashMap<>();
    urlMap.put("/**", defaultController());
    simpleUrlHandlerMapping.setUrlMap(urlMap);
    simpleUrlHandlerMapping.setOrder(1);
    return simpleUrlHandlerMapping;
}

Here the defaultController() method returns a @Controller , that you have defined for the given mapping, so DefaultController . The setOrder method defines a priority (order) of handlers, starting from 0. Of course some default HandlerMapping must be defined as a @Bean as well. More about such configuration you can find here .

Edit with some thoughts from @Tobia:

You need to remove the @RequestMapping annotation so that the controller is not picked up by RequestMappingHandlerMapping and implement the AbstractController interface to override the definition of controller in handleRequestInternal() .