How to run SPA webapp on Spring Boot 2.x

#java #javascript #spring #spa

TL;DR scroll down, get the sources below and taste it.

Most common web server with SPA flavor, All routes will forward to /index.html.
Yes. Spring boot also can do this. but it's pretty hard to figure it out until now. let's do this.

How much difficult to resolve this?
touch application.properties? NO.
write @Configuration? NOPE.
write @ControllerAdvice? NAH.
Why don't think easy peasy lemon squeezy?

just write a class with @Controller and implements ErrorController interface.
that's all. here's the code!

import org.springframework.boot.web.servlet.error.ErrorController;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@Controller
public class SpaErrorController implements ErrorController {

    @RequestMapping("/error")
    public Object error(HttpServletRequest request, HttpServletResponse response) {
        // place your additional code here (such as error logging...)
        if (request.getMethod().equalsIgnoreCase(HttpMethod.GET.name())) {
            response.setStatus(HttpStatus.OK.value()); // optional.
            return "forward:/index.html"; // forward to static SPA html resource.
        } else {
            return ResponseEntity.notFound().build(); // or your REST 404 blabla...
        }
    }

    @Override
    public String getErrorPath() {
        return "/error";
    }
}