gateway 2.2.5.RELEASE Mono<Void> filter 怎么拦截post请求 并添加参数

可以通过实现GatewayFilter接口来拦截post请求，并在请求中添加参数。

以下是一个示例代码，你可以在其中编写自己的逻辑：

@Component
public class CustomGatewayFilter implements GatewayFilter {

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        ServerHttpRequest request = exchange.getRequest();
        ServerHttpRequest.Builder builder = request.mutate();
        if (request.getMethod() == HttpMethod.POST) {
            // 添加参数
            MultiValueMap<String, String> queryParams = new LinkedMultiValueMap<>();
            queryParams.add("param1", "value1");
            queryParams.add("param2", "value2");

            // 替换请求体
            Flux<DataBuffer> body = exchange.getRequest().getBody();
            String bodyStr = DataBufferUtils.join(body).block().toString(StandardCharsets.UTF_8);
            bodyStr += "&" + URLEncodedUtils.format(queryParams, StandardCharsets.UTF_8);
            byte[] bytes = bodyStr.getBytes(StandardCharsets.UTF_8);
            DataBuffer buffer = exchange.getResponse().bufferFactory().wrap(bytes);
            builder = builder.method(request.getMethod())
                    .headers(httpHeaders -> {
                        httpHeaders.addAll(request.getHeaders());
                    })
                    .body(Mono.just(buffer));

            // 设置Content-Type
            exchange.getResponse().getHeaders().setContentType(MediaType.APPLICATION_FORM_URLENCODED);
        }
        ServerHttpRequest newRequest = builder.build();
        return chain.filter(exchange.mutate().request(newRequest).build());
    }
}

此过滤器将会在请求为POST方法时，添加两个参数param1和param2，并将参数拼接到请求体中。最后将请求体重新封装，并设置Content-Type为application/x-www-form-urlencoded。你可以根据自己的需要，修改这个过滤器的代码逻辑。