public static String getHeaders(final HttpHeaders headers) {
        Map<String, String> map = headers.entrySet().stream()
                .collect(Collectors.toMap(Map.Entry::getKey, entry -> String.join(",", entry.getValue())));
        return JsonUtils.toJson(map);
    }
get request header string.

@param headers request headers
@return header string
shenyu-plugin/shenyu-plugin-logging/shenyu-plugin-logging-common/src/main/java/org/apache/shenyu/plugin/logging/common/utils/LogCollectUtils.java