背景

使用Spring Cloud Gateway作为网关时有时候一个请求是既包含excel又包含json的表单数据,出于各种层面考虑网关需要获取并更新其中的json数据

依赖

  • Spring Boot版本:2.7.15
  • Hutool: 5.8.21
  • Java: 11

实现逻辑

实现分为2个部分

  1. 使用上文提到的ModifyRequestBodyGatewayFilterFactory类来修改请求体,这样最后就不用我们手动包装
  2. 核心service通过将表单转为String,然后根据其中的boundary进行分割,提取修改json报文部分后再进行组装

注意:示例代码的核心service处理的表单内容只是2个,Json数据的key指定为json,另一个excel文件流

自定义filter

@Component@Slf4jpublic class RequestModifyFilter implements GlobalFilter, Ordered {    @Autowired    private ModifyRequestBodyGatewayFilterFactory modifyRequestBodyFilter;    @Autowired    private JsonRequestBodyRewriteService jsonRequestBodyRewriteService;    @Autowired    private FormDataRequestBodyRewriteService formDataRequestBodyRewriteService;    @Override    public Mono filter(ServerWebExchange exchange, GatewayFilterChain chain) {        MediaType mediaType = exchange.getRequest().getHeaders().getContentType();        if (MediaType.APPLICATION_JSON.isCompatibleWith(mediaType)) {            // 纯json报文处理逻辑            return modifyRequestBodyFilter                    .apply(                            new ModifyRequestBodyGatewayFilterFactory.Config()                                    .setRewriteFunction(byte[].class, byte[].class, jsonRequestBodyRewriteService))                    .filter(exchange, chain);        } else if (MediaType.MULTIPART_FORM_DATA.isCompatibleWith(mediaType)) {            // form表单数据处理            return modifyRequestBodyFilter                    .apply(                            new ModifyRequestBodyGatewayFilterFactory.Config()                                    .setRewriteFunction(byte[].class, byte[].class, formDataRequestBodyRewriteService))                    .filter(exchange, chain);        } else {            return filter(exchange, chain);        }    }    @Override    public int getOrder() {        return OrderConstant.REQUEST_MODIFY_FILTER.getOrder();    }}

核心service

@Service@Slf4jpublic class FormDataRequestBodyRewriteService implements RewriteFunction {    private final String BOUNDARY_PREFIX_IN_CONTENT_TYPE = "----WebKitFormBoundary";    private final String BOUNDARY_PREFIX_IN_FORM_DATA = "------WebKitFormBoundary";    private final String BOUNDARY_SUFFIX = "--\r\n";    @Override    public Publisher apply(ServerWebExchange exchange, byte[] body) {        String finalResultString = "";        // 将表单转为字符串格式从而根据boundary分割表单数据。注意这里不能用默认编码        String request = StrUtil.str(body, StandardCharsets.ISO_8859_1);        // 获取boundary的随机字符信息        String contentType = exchange.getRequest().getHeaders().getContentType().toString();        String randomStr = contentType.substring(contentType.indexOf(BOUNDARY_PREFIX_IN_CONTENT_TYPE) + BOUNDARY_PREFIX_IN_CONTENT_TYPE.length());        // 这里和前端约定json数据的表单key为json        String keyPart = "^\r\nContent-Disposition: form-data; name=\"json\"";        Pattern r = Pattern.compile(keyPart);        // 根据表单内分割线进行分割。并通过关键段落keyPart来找到目标json数据        String[] split = request.split(BOUNDARY_PREFIX_IN_FORM_DATA + randomStr);        for (int x = 0; x < split.length - 1; x++) {            Matcher m = r.matcher(split[x]);            if (m.find()) {                // 找到了json报文部分数据                String originalJsonString = split[x];                // 找到 JSON 数据的起始和结束位置                int startIndex = originalJsonString.indexOf("{\"");                int endIndex = originalJsonString.indexOf("\"}") + 2;                // 提取 JSON 数据                String jsonData = originalJsonString.substring(startIndex, endIndex);                log.info("原始报文为:{}", jsonData);                JSONObject jsonObject = JSONUtil.parseObj(jsonData);                jsonObject.set("empId", "2345");                jsonObject.set("department", "Engineering");                String modifiedString = originalJsonString.substring(0, startIndex) + jsonObject + originalJsonString.substring(endIndex);                log.info("修改后报文为:{}", modifiedString);                // 重新组装split数组                finalResultString = finalResultString + modifiedString + BOUNDARY_PREFIX_IN_FORM_DATA + randomStr;            } else {                // 重组表单数据                finalResultString = finalResultString + split[x] + BOUNDARY_PREFIX_IN_FORM_DATA + randomStr;            }        }        // 补上最后一截数据        finalResultString = finalResultString + BOUNDARY_SUFFIX;        return Mono.just(finalResultString.getBytes(StandardCharsets.ISO_8859_1));    }}

相关代码

https://github.com/eastcukt/demo-gatway

其他

核心service获取表单中的json数据逻辑挺复杂,根本原因是没有合适的方法进行对象转换,如果有像使用@RequestPart(value = “json”)注解一样方便的方法将会非常方便也不用自己截取,各位大佬有更方便的方法感谢分享一下

参考

https://blog.csdn.net/qq_36966137/article/details/128536391