Whitelabel Error Page error (Spring Boot + React)

Question

localhost:9000 is opening fine on the browser. And if I navigate to a link from the menu like localhost:9000/about, it is working fine.

But if I hit localhost:9000/about directly without going to localhost:9000 then nothing happens on the local and if I do the same on server, following error is produced:

Whitelabel Error Page This application has no explicit mapping for /error, so you are seeing this as a fallback.

Mon Feb 12 14:09:05 IST 2018 There was an unexpected error (type=Not Found, status=404). No message available

Please help!!

Answer 1

When you hit http://localhost:9090/about directly, SpringBoot redirect To a /login.html. So, Redirect every page to index.html .

https://github.com/geowarin/boot-react/blob/master/backend/src/main/java/react/config/SinglePageAppConfig.java

The WebMvcConfigurer interface, starting with Spring 5, contains default implementations for all its methods. As a result, the abstract adapter (WebMvcConfigurerAdapter) class was marked as deprecated.

package your.package.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.util.StringUtils;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.resource.ResourceResolver;
import org.springframework.web.servlet.resource.ResourceResolverChain;

import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;

/**
 * Redirects every page to index.html
 * Used to handle the router
 */
@Configuration
public class SinglePageAppConfig implements WebMvcConfigurer {

  @Override
  public void addResourceHandlers(ResourceHandlerRegistry registry) {
    registry.addResourceHandler("/**")
      .addResourceLocations("classpath:/static/")
      .resourceChain(false)
      .addResolver(new PushStateResourceResolver());
  }

  private class PushStateResourceResolver implements ResourceResolver {
    private Resource index = new ClassPathResource("/static/index.html");
    private List<String> handledExtensions = Arrays.asList("html", "js", "json", "csv", "css", "png", "svg", "eot", "ttf", "woff", "appcache", "jpg", "jpeg", "gif", "ico");
    private List<String> ignoredPaths = Arrays.asList("api");

    @Override
    public Resource resolveResource(HttpServletRequest request, String requestPath, List<? extends Resource> locations, ResourceResolverChain chain) {
      return resolve(requestPath, locations);
    }

    @Override
    public String resolveUrlPath(String resourcePath, List<? extends Resource> locations, ResourceResolverChain chain) {
      Resource resolvedResource = resolve(resourcePath, locations);
      if (resolvedResource == null) {
        return null;
      }
      try {
        return resolvedResource.getURL().toString();
      } catch (IOException e) {
        return resolvedResource.getFilename();
      }
    }

    private Resource resolve(String requestPath, List<? extends Resource> locations) {
      if (isIgnored(requestPath)) {
        return null;
      }
      if (isHandled(requestPath)) {
        return locations.stream()
          .map(loc -> createRelative(loc, requestPath))
          .filter(resource -> resource != null && resource.exists())
          .findFirst()
          .orElseGet(null);
      }
      return index;
    }

    private Resource createRelative(Resource resource, String relativePath) {
      try {
        return resource.createRelative(relativePath);
      } catch (IOException e) {
        return null;
      }
    }

    private boolean isIgnored(String path) {
      return ignoredPaths.contains(path);
    }

    private boolean isHandled(String path) {
      String extension = StringUtils.getFilenameExtension(path);
      return handledExtensions.stream().anyMatch(ext -> ext.equals(extension));
    }
  }
}

Answer 2

This is happening because in your application you have not defined what your application should do when it will get url request localhost:9000. For every Request mapping you need to define the operation you want to perform. In your case for localhost:9000 you have to write what you want to do as you have done for local:9000/about.

@RequestMapping("")
@ResponseBody
Function_For_HandlingRequest{}