在获取入参的时候，get方式的接口可以直接获取到，但是post形式的body获取以后会造成无法再使用，所以必须经过一层转换以后再读取。

直接上代码

@Component
public class CacheBodyGatewayFilter implements GlobalFilter, Ordered {
    public static final String CACHE_REQUEST_BODY_OBJECT_KEY = "cachedRequestBodyObject";

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        if (exchange.getRequest().getHeaders().getContentType() == null) {
            return chain.filter(exchange);
        } else {
            return DataBufferUtils.join(exchange.getRequest().getBody())
                    .flatMap(dataBuffer -> {
                        DataBufferUtils.retain(dataBuffer);
                        Flux<DataBuffer> cachedFlux = Flux
                                .defer(() -> Flux.just(dataBuffer.slice(0, dataBuffer.readableByteCount())));
                        ServerHttpRequest mutatedRequest = new ServerHttpRequestDecorator(
                                exchange.getRequest()) {
                            @Override
                            public Flux<DataBuffer> getBody() {
                                return cachedFlux;
                            }

                        };
                        exchange.getAttributes().put(CACHE_REQUEST_BODY_OBJECT_KEY, cachedFlux);

                        return chain.filter(exchange.mutate().request(mutatedRequest).build());
                    });
        }
    }

    @Override
    public int getOrder() {
    	//这个代表了执行顺序，值越小越先执行 
        return Ordered.HIGHEST_PRECEDENCE;
    }
}

接下来是读取方法

@Component
public class AccessLogGlobalFilter implements GlobalFilter, Ordered {
    public static final String CACHE_REQUEST_BODY_OBJECT_KEY = "cachedRequestBodyObject";


    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        ServerHttpRequest request = exchange.getRequest();

        //Record only http requests (including https)
        String schema = request.getURI().getScheme();
        if ((!"http".equals(schema) && !"https".equals(schema))) {
            return chain.filter(exchange);
        }
		//我自定义的实体类，如果不需要 你可以直接删掉
        LogDTO logDTO = new LogDTO();
        logDTO.setPath(request.getURI().getPath());
        logDTO.setQueryParams(request.getQueryParams());
        logDTO.setMethod(request.getMethod().name());
        logDTO.setIp(request.getRemoteAddress().getHostName());
        logDTO.setUserAgent(request.getHeaders().getFirst("User-Agent"));
        exchange.getAttributes().put("startTime", System.currentTimeMillis());


        //获取request body
        Flux<DataBuffer> cachedBody = exchange.getAttribute(CACHE_REQUEST_BODY_OBJECT_KEY);
        if(cachedBody!=null){
            String raw = toRaw(cachedBody);
            logDTO.setParams(raw);
        }


        return returnMono(chain, exchange, logDTO);
    }

    private Mono<Void> returnMono(GatewayFilterChain chain, ServerWebExchange exchange, LogDTO logDTO) {
        return chain.filter(exchange).then(Mono.fromRunnable(() -> {
            Long startTime = exchange.getAttribute("startTime");
            if (startTime != null) {
                long executeTime = (System.currentTimeMillis() - startTime);
                logDTO.setTime(executeTime);
                logDTO.setResultCode(Objects.requireNonNull(exchange.getResponse().getStatusCode()).value());
                StaticLog.info("=================================");
                StaticLog.info("请求方式：[{}]", logDTO.getMethod());
                StaticLog.info("路径：[{}]", logDTO.getPath());
                StaticLog.info("IP：[{}]", logDTO.getIp());
                StaticLog.info("UserAgent：[{}]", logDTO.getUserAgent());
                StaticLog.info("请求格式[{}]", exchange.getResponse().getHeaders().getContentType());
                StaticLog.info("时长：[{}]", executeTime);
                StaticLog.info("code：[{}]", logDTO.getResultCode());
                StaticLog.info("body：[{}]", logDTO.getParams());
            }
        }));
    }

    @Override
    public int getOrder() {
    	//这个filter的执行顺序要在 CacheBodyGatewayFilter 类之后 否则找不到缓存的值
        return Ordered.HIGHEST_PRECEDENCE+1;
    }

    /**
     * 用于获取请求参数
     *
     * @param body
     * @return
     */
    private static String toRaw(Flux<DataBuffer> body) {
        AtomicReference<String> rawRef = new AtomicReference<>();
        body.subscribe(buffer -> {
            byte[] bytes = new byte[buffer.readableByteCount()];
            buffer.read(bytes);
            DataBufferUtils.release(buffer);
            rawRef.set(Strings.fromUTF8ByteArray(bytes));
        });
        return rawRef.get();
    }

}