您需要在 POST body 中发送 JSON，但您将其附加到查询参数中.

You need to send JSON in the POST body, but you are attaching it to the query parameters instead.

改用data，只对外部结构进行编码:

Use data instead, and only encode the outer structure:

result=req.post(wsAddr+methodPath,
                data=json.dumps({'composite': cType}),
                headers=headers)

如果您对 cType 进行编码，您将发送一个包含另一个 JSON 编码字符串的 JSON 编码字符串，该字符串又包含您的 cType 字典.

If you encoded cType, you'd send a JSON-encoded string containing another JSON-encoded string, which in turn contains your cType dictionary.