我的超能力建议您希望将 body 作为 json 字符串发送，而不是作为转换为字符串的字典发送.

My psychic powers suggest you want to send body as a string of json, not as a dictionary that's converted to a string.

body = '{"where" : {"deviceType" : "ios"}, "data" : {"alert" : "vvv"}}'

注意对 json 元素使用双引号.

Notice the use of double-quotes for the json elements.