官网相关案例：
Spring Cloud Gateway
https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the-modifyresponsebody-gatewayfilter-factory
ModifyRequestBodyGatewayFilterFactory类:
https://github.com/spring-cloud/spring-cloud-gateway/blob/3.1.x/spring-cloud-gateway-server/src/main/java/org/springframework/cloud/gateway/filter/factory/rewrite/ModifyResponseBodyGatewayFilterFactory.javahttps://github.com/spring-cloud/spring-cloud-gateway/blob/3.1.x/spring-cloud-gateway-server/src/main/java/org/springframework/cloud/gateway/filter/factory/rewrite/ModifyResponseBodyGatewayFilterFactory.java
相关代码：
import cn.hutool.core.collection.CollUtil;
import cn.hutool.core.util.StrUtil;
import com.alibaba.fastjson.JSONObject;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.SneakyThrows;
import lombok.extern.slf4j.Slf4j;
import org.reactivestreams.Publisher;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.NettyWriteResponseFilter;
import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferFactory;
import org.springframework.core.io.buffer.DataBufferUtils;
import org.springframework.core.io.buffer.DefaultDataBufferFactory;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.http.server.reactive.ServerHttpResponseDecorator;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;import java.util.List;/*** @Author: meng* @Description: 自定义返回体 - 借鉴原生类ModifyRequestBodyGatewayFilterFactory实现* https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#the* -modifyresponsebody-gatewayfilter-factory* @Date: 2023/4/18 13:37* @Version: 1.0*/
@Slf4j
@Component
public class ResponseGatewayFilterFactory extends AbstractGatewayFilterFactory<ResponseGatewayFilterFactory.Config> {public ResponseGatewayFilterFactory() {super(Config.class);}@Data@AllArgsConstructor@NoArgsConstructorpublic static class Config {// 不需要自定义的接口List<String> pathExclude;}@Overridepublic GatewayFilter apply(Config config) {RewriteResponseGatewayFilter rewriteResponseGatewayFilter = new RewriteResponseGatewayFilter(config);return rewriteResponseGatewayFilter;}public class RewriteResponseGatewayFilter implements GatewayFilter, Ordered {private Config config;public RewriteResponseGatewayFilter(Config config) {this.config = config;}@Overridepublic Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {// 不需要自定义的接口，直接返回log.info("pathExclude:{}", config.pathExclude);if (CollUtil.isNotEmpty(config.pathExclude)) {long count = config.pathExclude.stream().filter(uri -> StrUtil.contains(exchange.getRequest().getPath().toString(), uri)).count();if (count > 0) {return chain.filter(exchange);}}String appId = exchange.getRequest().getHeaders().getFirst("X-APPID");if (StrUtil.isBlank(appId)) {return buildResponse(exchange, HttpStatus.UNAUTHORIZED.value(), "appId不能为空");}ServerHttpResponse originalResponse = exchange.getResponse();DataBufferFactory bufferFactory = originalResponse.bufferFactory();try {ServerHttpResponseDecorator decoratedResponse = new ServerHttpResponseDecorator(originalResponse) {@Overridepublic Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {if (body instanceof Flux) {Flux<? extends DataBuffer> fluxBody = Flux.from(body);return super.writeWith(fluxBody.buffer().map(dataBuffers -> {byte[] newContent = new byte[0];try {DataBufferFactory dataBufferFactory = new DefaultDataBufferFactory();DataBuffer join = dataBufferFactory.join(dataBuffers);byte[] content = new byte[join.readableByteCount()];join.read(content);DataBufferUtils.release(join);// 获取响应数据String responseStr = new String(content, "UTF-8");// 修改响应数据JSONObject jsonObject = new JSONObject();jsonObject.put("code", HttpStatus.UNAUTHORIZED.value());jsonObject.put("message", "请求成功");jsonObject.put("data", responseStr);String message = jsonObject.toJSONString();newContent = message.getBytes("UTF-8");originalResponse.getHeaders().setContentLength(newContent.length);}catch (Exception e) {log.error("appId:{}, responseStr exchange error:{}", appId, e);throw new RuntimeException(e);}return bufferFactory.wrap(newContent);}));}return super.writeWith(body);}@Overridepublic Mono<Void> writeAndFlushWith(Publisher<? extends Publisher<? extends DataBuffer>> body) {return writeWith(Flux.from(body).flatMapSequential(p -> p));}};return chain.filter(exchange.mutate().response(decoratedResponse).build());}catch (Exception e) {log.error("RewriteResponse error:{}", e);return Mono.error(new Exception("RewriteResponse fail", e));}}@Overridepublic int getOrder() {return NettyWriteResponseFilter.WRITE_RESPONSE_FILTER_ORDER - 2;}}@SneakyThrowspublic static Mono<Void> buildResponse(ServerWebExchange exchange, int code, String message) {ServerHttpResponse response = exchange.getResponse();response.setStatusCode(HttpStatus.OK);response.getHeaders().add(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_UTF8_VALUE);JSONObject jsonObject = new JSONObject();jsonObject.put("code", code);jsonObject.put("message", message);jsonObject.put("data", "");byte[] bytes = jsonObject.toJSONString().getBytes("UTF-8");DataBuffer bodyDataBuffer = response.bufferFactory().wrap(bytes);return response.writeWith(Mono.just(bodyDataBuffer));}}
