Reverse proxy using spring-cloud-gateway-mvc

ReverseProxyController.java

package com.example.reverseproxy;

import com.example.ApiResponse;
import org.springframework.cloud.gateway.mvc.ProxyExchange;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletRequest;
import java.util.Objects;

@RestController
@RequestMapping(ReverseProxyController.PROXY_MAPPING_PREFIX)
public class ReverseProxyController {

    public static final String PROXY_MAPPING_PREFIX = "/proxy/";

    @RequestMapping("/**")
    public ResponseEntity<?> postProxy(ProxyExchange<ApiResponse> proxyExchange, HttpServletRequest request) {
        String path = proxyExchange.path(PROXY_MAPPING_PREFIX);
        String queryString = request.getQueryString();
        if (null != queryString) path = path + "?" + queryString;
        proxyExchange.uri("http://localhost:8092/" + path);
        return switch (Objects.requireNonNull(HttpMethod.resolve(request.getMethod()))) {
            case POST -> proxyExchange.post(responseEntity -> {
                if (responseEntity.getStatusCode() == HttpStatus.OK) {
                    System.out.printf("POST Response: %s\n", responseEntity.getBody());
                }
                return responseEntity;
            });
            case GET -> proxyExchange.get(responseEntity -> {
                if (responseEntity.getStatusCode() == HttpStatus.OK) {
                    System.out.printf("GET Response: %s\n", responseEntity.getBody());
                }
                return responseEntity;
            });
            default -> ResponseEntity.status(HttpStatus.METHOD_NOT_ALLOWED).build();
        };
    }

}