详解Java接口签名(Signature)实现方案

 //引用jackson依赖
    @Autowired
    private ObjectMapper objectMapper;
    @Value("${appsecret}")
    private String appSecret;
  
  /**
     * 验证签名
     * @param preInfoItem
     * @return
     */
    boolean checkSignature(PreInfoItem preInfoItem) throws JsonProcessingException, IllegalAccessException {
        String signature="signature";
        String appkey="appkey";
        String timestamp="timestamp";
        String noncestr="noncestr";
        HttpServletRequest request = ServletUtils.getRequest();
        String headerSignature = request.getHeader(signature);
        String headerAppkey = request.getHeader(appkey);
        String headerTimestamp = request.getHeader(timestamp);
        String headerNoncestr = request.getHeader(noncestr);
		//因为需要排序，直接使用TreeMap
        Map<String,Object> parms=new TreeMap<>();
        parms.put(appkey,headerAppkey);
        parms.put(timestamp,headerTimestamp);
        parms.put(noncestr,headerNoncestr);
        Map<String, Object> stringObjectMap = objectToMap(parms, preInfoItem);
        String s = buildSignature(stringObjectMap);
        //签名比对
        if (s.equals(headerSignature)){
            return true;
        }
        return false;
    }
    Map<String,Object> objectToMap(Map<String,Object> map,Object o){
        Field[] declaredFields = o.getClass().getDeclaredFields();
        for (Field field : declaredFields) {
            field.setAccessible(true);
            try {
                if (field.getName() instanceof String){
                    map.put(field.getName(),field.get(o));
                }
            }catch (IllegalAccessException e){
                throw new CustomException("对象转map异常");
            }
        }
        return map;
    }
  private String buildSignature(Map<String,Object> maps){
      String s2;
      try {
            StringBuffer s = null;
            String s1 = objectMapper.writeValueAsString(maps);
            //添加appSecret
            s.append(s1).append(appSecret);
             s2 = DigestUtils.md5DigestAsHex(s.toString().getBytes());
        }catch (JsonProcessingException e){
            throw new CustomException("map转json异常");
        }
        return s2;
    }