java.lang.String cannot be cast to com.alibaba.fastjson.JSONObject

调用api，发现执行

ResponseEntity res = HttpHelper.proxyToProduceParamURL(restTemplate, "POST", this.host + resource,
        headers, params, null);

这句时，返回到res为null。

debug进入后发现了错误。

是数据格式的问题：

对于

["a"]

[{"a":"b","c":"d","e":[{"f":{"g":"h","i":"j","k":"l"}}]},{"m":"n","o":"p","q":[{"r":{"s":"t","u":"v","w":"x"}}]}]

{"a":"b","c":0,"d":2}

这类格式的参数值，要用

params.put("xxx", Arrays.asList(JSONObject.toJSONString(param.get("xxx"))));

来传参。

而不是

params.put("xxx", Arrays.asList(param.get("xxx").toString()));