Whitelabel Error Page error (Spring Boot + React) - reactjs

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

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{}

Answer 2

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 3

in Application
#Bean
public WebServerFactoryCustomizer<ConfigurableWebServerFactory> webServerFactoryCustomizer() {
return factory -> {
ErrorPage error404Page = new ErrorPage(HttpStatus.NOT_FOUND, "/index.html");
factory.addErrorPages(error404Page);
};
}
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