Spring Boot with redirecting with single page angular2

If you’re tired of trying to solve this problem by following so many conflicting solutions – look here!!

After hours upon hours trying to follow all the scattered advice from dozens of stack overflow and blog posts, I’ve finally found the minimum PURE spring boot + angular 6 application to always redirect to index.html after a refresh on a non-root page WHILE maintaining all your REST API endpoint paths. No @EnableWebMvc, no @ControllerAdvice, no changes to application.properties, no custom ResourceHandlerRegistry modifications, just simplicity:

Very important pre-requisite

You *must* include the output of ng build into Spring’s resources/static folder. You can accomplish this via the maven-resources-plugin. Learn here: Copying multiple resource directories to independent target directories with maven

Code

@Controller
@SpringBootApplication
public class MyApp implements ErrorController {

    public static void main(String[] args) {
        SpringApplication.run(MyApp.class, args);
    }

    private static final String PATH = "/error";

    @RequestMapping(value = PATH)
    public String error() {
        return "forward:/index.html";
    }

    @Override
    public String getErrorPath() {
        return PATH;
    }
}

Reasoning

• Including the output of ng-build into resources/static at build time allows spring view redirects ("forward:/index.html") to succeed. It seems spring cannot redirect to anything outside of the resources folder so if you’re trying to access pages at the root of the site, it won’t work.
• With default functionality (i.e. no additions of @EnableWebMvc or changes to application.properties) navigating to / automatically serves the index.html (iff it was included in the resources/static folder) so no need to make changes there.
• With default functionality (as stated above), any error encountered in a spring boot app routes to /error and implementing ErrorController overrides that behavior to – you guessed it – route to index.html which allows Angular to take over the routing.

Remarks

• Don’t settle for the HashLocationStrategy to get over this problem as it is not recommended by Angular: https://angular.io/guide/router#which-strategy-is-best