spring cloud gateway中如何读取请求参数

import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferUtils;
import org.springframework.Http.HttpMethod;
import org.springframework.http.server.Reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpRequestDecorator;
import org.springframework.stereotype.Component;
import org.springframework.WEB.server.ServerWebExchange;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
 
import java.NIO.charset.StandardCharsets;
import java.util.Map;
import java.util.stream.Collectors;
 

@Slf4j
@Component
public class LoggerFilter implements GlobalFilter {
 
	@Override
	public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
		ServerHttpRequest request = exchange.getRequest();
		String method = request.getMethodValue();
 
		if (HttpMethod.POST.matches(method)) {
			return DataBufferUtils.join(exchange.getRequest().getBody())
					.flatMap(dataBuffer -> {
						byte[] bytes = new byte[dataBuffer.readableByteCount()];
						dataBuffer.read(bytes);
						String bodyString = new String(bytes, StandardCharsets.UTF_8);
						logtrace(exchange, bodyString);
						exchange.getAttributes().put("POST_BODY", bodyString);
						DataBufferUtils.release(dataBuffer);
						Flux<DataBuffer> cachedFlux = Flux.defer(() -> {
							DataBuffer buffer = exchange.getResponse().bufferFactory()
									.wrap(bytes);
							return Mono.just(buffer);
						});
 
						ServerHttpRequest mutatedRequest = new ServerHttpRequestDecorator(
								exchange.getRequest()) {
							@Override
							public Flux<DataBuffer> getBody() {
								return cachedFlux;
							}
						};
						return chain.filter(exchange.mutate().request(mutatedRequest)
								.build());
					});
		} else if (HttpMethod.GET.matches(method)) {
			Map m = request.getQueryParams();
			logtrace(exchange, m.toString());
		}
		return chain.filter(exchange);
	}
 
	
	private void logtrace(ServerWebExchange exchange, String param) {
		ServerHttpRequest serverHttpRequest = exchange.getRequest();
		String path = serverHttpRequest.getURI().getPath();
		String method = serverHttpRequest.getMethodValue();
		String headers = serverHttpRequest.getHeaders().entrySet()
				.stream()
				.map(entry -> "            " + entry.geTKEy() + ": [" + String.join(";", entry.getValue()) + "]")
				.collect(Collectors.joining("\n"));
		log.info("\n" + "----------------             ----------------             ---------------->>\n" +
						"HttpMethod : {}\n" +
						"Uri        : {}\n" +
						"Param      : {}\n" +
						"Headers    : \n" +
						"{}\n" +
						"\"<<----------------             ----------------             ----------------"
				, method, path, param, headers);
	}
 
}

// 参考api文档中GatewapFilter中“添加请求参数拦截器”：AddRequestParameterGatewayFilterFactory.java
 
            //记录日志
            //logger.info("全局参数处理: {} url：{} 参数：{}",method.toString(),serverHttpRequest.getURI().getRawPath(),newRequestQueryParams.toString());
            // 获取原参数
            URI uri = serverHttpRequest.getURI();
            StringBuilder query = new StringBuilder();
            String originalQuery = uri.getRawQuery();
            if (org.springframework.util.StringUtils.hasText(originalQuery)) {
                query.append(originalQuery);
                if (originalQuery.charAt(originalQuery.length() - 1) != '&') {
                    query.append('&');
                }
            }
            // 添加查询参数
            query.append(ServiceConstants.COMMON_PARAMETER_ENTERPRISEID+"="+authenticationVO.getEnterpriseId()
                    +"&"+ServiceConstants.COMMON_PARAMETER_USERID+"="+authenticationVO.getUserId());
 
            // 替换查询参数
            URI newUri = UriComponentsBuilder.fromUri(uri)
                    .replaceQuery(query.toString())
                    .build(true)
                    .toUri();
 
            ServerHttpRequest request = exchange.getRequest().mutate().uri(newUri).build();
            return chain.filter(exchange.mutate().request(request).build());

//从请求里获取Post请求体
                    String bodyStr = resolveBodyFromRequest(serverHttpRequest);
                    String userId = "123";
// 这种处理方式，必须保证post请求时，原始post表单必须有数据过来，不然会报错
                    if (StringUtils.isEmpty(bodyStr)) {
                        logger.error("请求异常：{} POST请求必须传递参数", serverHttpRequest.getURI().getRawPath());
                        ServerHttpResponse response = exchange.getResponse();
                        response.setStatusCode(httpstatus.BAD_REQUEST);
                        return response.setComplete();
                    }
                    //application/x-www-fORM-urlencoded和application/JSON才添加参数
                    //其他上传文件之类的，不做参数处理，因为文件流添加参数，文件原格式就会出问题了
                   
                    // 新增body参数
                    if (MediaType.APPLICATION_jsON_VALUE.equalsIgnoreCase(contentType)) {
                        JSONObject jsonObject = new JSONObject(bodyStr);
                        jsonObject.put("userId", userId);
                        bodyStr = jsonObject.toString();
                    }
                    //记录日志
                    logger.info("全局参数处理: {} url：{} 参数：{}", method.toString(), serverHttpRequest.getURI().getRawPath(), bodyStr);
                    //下面的将请求体再次封装写回到request里，传到下一级，否则，由于请求体已被消费，后续的服务将取不到值
                    URI uri = serverHttpRequest.getURI();
                    URI newUri = UriComponentsBuilder.fromUri(uri).build(true).toUri();
                    ServerHttpRequest request = exchange.getRequest().mutate().uri(newUri).build();
                    DataBuffer bodyDataBuffer = stringBuffer(bodyStr);
                    Flux<DataBuffer> bodyFlux = Flux.just(bodyDataBuffer);
                    // 定义新的消息头
                    HttpHeaders headers = new HttpHeaders();
                    headers.putAll(exchange.getRequest().getHeaders());
                    // 添加消息头
//                    headers.set(ServiceConstants.shiro_SESSION_PRINCIPALS,GsonUtils.toJson(authenticationVO));
                    // 由于修改了传递参数，需要重新设置CONTENT_LENGTH，长度是字节长度，不是字符串长度
                    int length = bodyStr.getBytes().length;
                    headers.remove(HttpHeaders.CONTENT_LENGTH);
                    headers.setContentLength(length);
                    // 设置CONTENT_TYPE
                    if (StringUtils.isEmpty(contentType)) {
                        headers.set(HttpHeaders.CONTENT_TYPE, contentType);
                    }
                    // 由于post的body只能订阅一次，由于上面代码中已经订阅过一次body。所以要再次封装请求到request才行，不然会报错请求已经订阅过
                    request = new ServerHttpRequestDecorator(request) {
                        @Override
                        public HttpHeaders getHeaders() {
                            long contentLength = headers.getContentLength();
                            HttpHeaders httpHeaders = new HttpHeaders();
                            httpHeaders.putAll(super.getHeaders());
                            if (contentLength > 0) {
                                httpHeaders.setContentLength(contentLength);
                            } else {
                                // TODO: this causes a 'HTTP/1.1 411 Length Required' on httpbin.org
                                httpHeaders.set(HttpHeaders.TRANSFER_ENcoding, "chunked");
                            }
                            return httpHeaders;
                        }
                        @Override
                        public Flux<DataBuffer> getBody() {
                            return bodyFlux;
                        }
                    };
                    //封装request，传给下一级
                    request.mutate().header(HttpHeaders.CONTENT_LENGTH, Integer.toString(bodyStr.length()));
                    return chain.filter(exchange.mutate().request(request).build());
   
    private String resolveBodyFromRequest(ServerHttpRequest serverHttpRequest) {
        //获取请求体
        Flux<DataBuffer> body = serverHttpRequest.getBody();
        AtomicReference<String> bodyRef = new AtomicReference<>();
        body.subscribe(buffer -> {
            CharBuffer charBuffer = StandardCharsets.UTF_8.decode(buffer.asByteBuffer());
            DataBufferUtils.release(buffer);
            bodyRef.set(charBuffer.toString());
        });
        //获取request body
        return bodyRef.get();
    }

private DataBuffer stringBuffer(String value) {
byte[] bytes = value.getBytes(StandardCharsets.UTF_8);
NettyDataBufferFactory nettyDataBufferFactory = new NettyDataBufferFactory(ByteBufAllocator.DEFAULT);
DataBuffer buffer = nettyDataBufferFactory.allocateBuffer(bytes.length);
buffer.write(bytes);
return buffer;
}