Question

我的后端可以返回JSON或纯字符串数据作为响应。

EVERY_SECOND

在回复回调中，如何检查回复let task = session.dataTask(with: request as URLRequest) { data, response, error in if error == nil { // Handle response data, but it could be JSON & it could also be String data, how to check and distinguish & handle respectively? if let data = data { // it fails here if the data is String if let jsonDataDict = try? JSONSerialization.jsonObject(with: data) as? JSONDataDict { } else { } } }是data格式还是JSON，如何分别处理？

Answer 1

尝试使用String初始化程序将UTf8作为字符串编码传递数据

if let data = data {
                // it fails here if the data is String
                if let jsonDataDict = try? JSONSerialization.jsonObject(with: data) as? JSONDataDict {

                } else {
                if let dataString = String(data: data, encoding: .utf8){
                      debugPrint(dataString)
                }
          }

    }

Answer 2

 let jsonDataDict = try? JSONSerialization.jsonObject(with: data) as? JSONDataDict

 if let strJSON = jsonDataDict as? [String:String] //you can cast in string as
 {
    if strJSON?.isEmpty == false {
        //It is empty
    } 

 }

Answer 3

if let data = data {
        if data is Data {
            //do operation with Data
            if let jsonDataDict = try? JSONSerialization.jsonObject(with: data) as? JSONDataDict {
            }
        }
        else if data is String {
            //do operation with string
        }
    }

AppleDoc

使用类型检查运算符（is）检查实例是否属于某些子类型。如果是，则类型检查运算符返回true instance属于该子类类型，如果不是，则为false。

分别处理回调中的JSON响应数据和字符串响应数据

3 个答案: