private static String encodeChunk(String value, FragmentType type, Charset charset) {
    byte[] data = value.getBytes(charset);
    ByteArrayOutputStream encoded = new ByteArrayOutputStream();
    // 依次對每個byte編碼
    for (byte b : data) {
      // 對于一些字符不進(jìn)行編碼
      if (type.isAllowed(b)) {
        encoded.write(b);
      } else {
        /* percent encode the byte */
        pctEncode(b, encoded);
      }
    }
    return new String(encoded.toByteArray());
  }
 
boolean isAllowed(int c) {
        return this.isPchar(c) || (c == '/');
      }
 
protected boolean isPchar(int c) {
      return this.isUnreserved(c) || this.isSubDelimiter(c) || c == ':' || c == '@';
    }
 
protected boolean isUnreserved(int c) {
      return this.isAlpha(c) || this.isDigit(c) || c == '-' || c == '.' || c == '_' || c == '~';
    }
 
protected boolean isAlpha(int c) {
      return (c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z');
    }
 
protected boolean isDigit(int c) {
      return (c >= '0' && c <= '9');
    }
 
protected boolean isSubDelimiter(int c) {
      return (c == '!') || (c == '$') || (c == '&') || (c == '\'') || (c == '(') || (c == ')')
          || (c == '*') || (c == '+') || (c == ',') || (c == ';') || (c == '=');
    }

// 2、SynchronousMethodHandler.invoke 
public Object invoke(Object[] argv) throws Throwable {
    // 2-1、先實(shí)例化RequestTemplate 此處encode參數(shù)
    RequestTemplate template = buildTemplateFromArgs.create(argv);
    Retryer retryer = this.retryer.clone();
    while (true) {
      try {
        return executeAndDecode(template);
      } catch (RetryableException e) {
        try {
          retryer.continueOrPropagate(e);
        } catch (RetryableException th) {
          Throwable cause = th.getCause();
          if (propagationPolicy == UNWRAP && cause != null) {
            throw cause;
          } else {
            throw th;
          }
        }
        if (logLevel != Logger.Level.NONE) {
          logger.logRetry(metadata.configKey(), logLevel);
        }
        continue;
      }
    }
  }
 
  Object executeAndDecode(RequestTemplate template) throws Throwable {
    // 2-2、executeAndDecode方法，將RequestTemplate build為request
    Request request = targetRequest(template);
 
    if (logLevel != Logger.Level.NONE) {
      logger.logRequest(metadata.configKey(), logLevel, request);
    }
 
    Response response;
    long start = System.nanoTime();
    try {
      // 2-3、execute 執(zhí)行 訪問原程服務(wù)
      response = client.execute(request, options);
    } catch (IOException e) {
      if (logLevel != Logger.Level.NONE) {
        logger.logIOException(metadata.configKey(), logLevel, e, elapsedTime(start));
      }
      throw errorExecuting(request, e);
    }
    long elapsedTime = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - start);
 
    boolean shouldClose = true;
    try {
      if (logLevel != Logger.Level.NONE) {
        response =
            logger.logAndRebufferResponse(metadata.configKey(), logLevel, response, elapsedTime);
      }
      if (Response.class == metadata.returnType()) {
        if (response.body() == null) {
          return response;
        }
        if (response.body().length() == null ||
            response.body().length() > MAX_RESPONSE_BUFFER_SIZE) {
          shouldClose = false;
          return response;
        }
        // Ensure the response body is disconnected
        byte[] bodyData = Util.toByteArray(response.body().asInputStream());
        return response.toBuilder().body(bodyData).build();
      }
      if (response.status() >= 200 && response.status() < 300) {
        if (void.class == metadata.returnType()) {
          return null;
        } else {
          Object result = decode(response);
          shouldClose = closeAfterDecode;
          return result;
        }
      } else if (decode404 && response.status() == 404 && void.class != metadata.returnType()) {
        Object result = decode(response);
        shouldClose = closeAfterDecode;
        return result;
      } else {
        throw errorDecoder.decode(metadata.configKey(), response);
      }
    } catch (IOException e) {
      if (logLevel != Logger.Level.NONE) {
        logger.logIOException(metadata.configKey(), logLevel, e, elapsedTime);
      }
      throw errorReading(request, response, e);
    } finally {
      if (shouldClose) {
        ensureClosed(response.body());
      }
    }
  }
 
  long elapsedTime(long start) {
    return TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - start);
  }
 
  Request targetRequest(RequestTemplate template) {
    // 此處會先執(zhí)行攔截器
    for (RequestInterceptor interceptor : requestInterceptors) {
      interceptor.apply(template);
    }
    return target.apply(template);
  }
 
  Object decode(Response response) throws Throwable {
    try {
      // 2-4、將response decode 
      return decoder.decode(response, metadata.returnType());
    } catch (FeignException e) {
      throw e;
    } catch (RuntimeException e) {
      throw new DecodeException(response.status(), e.getMessage(), e);
    }
  }

@FeignClient(
?? ?name = "ocr-api",
?? ?url = "${orc.idcard-url}",
?? ?fallbackFactory = OcrClientFallbackFactory.class
)
public interface OcrClient {
?
?? ?@PostMapping(
?? ??? ?value = "/v1/demo/idcard",
?? ??? ?headers = {"content-type=application/x-www-form-urlencoded"}
?? ?)
?? ?OcrBaseResponse<IdCardResponse> getIdCarInfo(@RequestBody MultiValueMap<String, Object> request);
}

? ? // 測試代碼
?? ?@Resource
?? ?private OcrClient ocrClient;
?? ?@GetMapping("getIdCardInfo")
?? ?public Message getIdCardInfo() {
?? ??? ?MultiValueMap<String, Object> req = new LinkedMultiValueMap<>();
?? ??? ?req.add("request_id", 12343531123L);
?? ??? ?req.add("img_url", "xxx.jpg");
?? ??? ?req.add("source", -1);
?? ??? ?req.add("out_business_id", 1321434234L);
?? ??? ?OcrBaseResponse<IdCardResponse> idCarInfo = ocrClient.getIdCarInfo(req);
?? ??? ?return Message.success(idCarInfo);
?? ?}