尝试将json解析为类对象失败

我需要帮助使用Swift解析json。我无法使用swift将它们解析为类对象的数组。我尝试的是将json键值绑定到一个对象数组中并返回。但是，我无法处理这些类型。这太令人困惑了

谁能帮帮我吗

我所拥有的json：

{ 
 "mass_info1":
  [{
    "mass_id":7780, 
    "mass_date":"5/1/2019", 
    "mass_time":"7:30 PM", 
    "mass_location":"", 
    "mass_description": “Blah1” 
  } ] , 
 "mass_info2":
  [ { 
    "mass_id":7781, 
    "mass_date":"6/10/2019", 
    "mass_time":"7:30 PM", 
    "mass_location”:”1234 some place Los Angeles”, 
    "mass_description": “blah2” 
  } ] , 
 "mass_info3":
  [ { 
    "mass_id":7783, 
    "mass_date":"5/21/2019", 
    "mass_time":"7:30 PM", 
    "mass_location":"", 
    "mass_description": “blah3” 
  } ] , 
 "mass_info4":
  [ {
    "mass_id":1115, 
    "mass_date":"4/5/2019", 
    "mass_time":"2:30 PM", 
    "mass_location":"4050 Mission Ave, Oceanside, CA 92057", 
    "mass_description": “blah4”
  } ] 
}

类MassInfoObject导入基础

以及我从URLSession获取json的代码

    func getjson()->[MassInfoObject]? {
            let urlPath = "http://myclassinfo.com/dev/json.php"
            let url = URL(string: urlPath)
            var massObjArray = [MassInfoObject]()
            var index:Int = 0
            let task = URLSession.shared.dataTask(with: url!) { data, response, error in
                print("Task completed")

                guard data != nil && error == nil else {
                    //print(error?.localizedDescription)
                    return
                }
                do {
                    if let jsonResult = try JSONSerialization.jsonObject(with: data!, options: []) as? NSDictionary {

                        for (key, value) in jsonResult {
                            //print("Value: \(value) for key: \(key)")
                            if let results = jsonResult[key] as? [String] 
      {

                                let dict = results[index].toJSON() as? [String:AnyObject] // can be any type here
                                for (key,value) in dict!{
                                    let result2 = dict![key] as! String
                                    print (result2)
                                }
                             }

                        }
                    }
                } catch let parseError as NSError {
                    print("JSON Error \(parseError.localizedDescription)")
                }
            }

            task.resume()
            return massObjArray
        }

---

您试图解析的json没有非常合理的结构。如果您可以控制json，那么应该首先处理它。如果您没有控制权，我建议在解析之前在客户端转换json

在操场上进行以下工作：

let str = """
{ "mass_info1": [{ "mass_id":7780, "mass_date":"5/1/2019", "mass_time":"7:30 PM", "mass_location":"", "mass_description": "Blah1"
} ] ,
"mass_info2":  [ { "mass_id":7781,  "mass_date":"6/10/2019", "mass_time":"7:30 PM", "mass_location":"1234 some place Los Angeles",  "mass_description": "Blah2"
} ] ,
"mass_info3":
[ { "mass_id":7783,  "mass_date":"5/21/2019",  "mass_time":"7:30 PM",  "mass_location":"",  "mass_description": "blah3"
} ] ,
"mass_info4":
[ { "mass_id":1115,  "mass_date":"4/5/2019", "mass_time":"2:30 PM", "mass_location":"4050 Mission Ave, Oceanside, CA 92057",  "mass_description": "blah4"
} ]
}
"""

struct MassInfoObject: Codable {
    var mass_id: Int
    var mass_date: String?
    var mass_time: String?
    var mass_location: String?
    var mass_description: String?
}

let data = str.data(using: .utf8)!

let json = try JSONSerialization.jsonObject(with: data, options: []) as? [String: [[String: Any]]]

let jsonArray = json!.values.map { $0 }

let cleanedJson = try JSONSerialization.data(withJSONObject: jsonArray, options: [])

let decoder = JSONDecoder()
let items = try decoder.decode([[MassInfoObject]].self, from: cleanedJson)

第一步是将json转换为易于解析的内容。因为现在MassInfoObject符合

Codable

，所以可以使用一个简单的JSONDecoder来解码对象数组，这只是一行代码

另外，在您的网络代码中，您正在调用一个异步任务，但是您的任务将立即返回，这是行不通的。从

getJson

函数返回时，还没有结果。最简单的方法是使用一个可以调用结果的闭包：

在您的网络代码中，它看起来是这样的：

func getjson(handler: @escaping ([MassInfoObject]?)->()) {
  let urlPath = "http://myclassinfo.com/dev/json.php"
  let url = URL(string: urlPath)
  let task = URLSession.shared.dataTask(with: url!) { data, response, error in
     print("Task completed")

     guard let data = data && error == nil else {
        //print(error?.localizedDescription)
        return
     }
     do {
        let json = try JSONSerialization.jsonObject(with: data, options: []) as? [String: [[String: Any]]]
        let jsonArray = json!.values.map { $0 }
        let cleanedJson = try JSONSerialization.data(withJSONObject: jsonArray, options: [])
        let decoder = JSONDecoder()
        let items = try decoder.decode([[MassInfoObject]].self, from: cleanedJson).compactMap { $0 }

        handler(items)

     } catch let parseError as NSError {
        print("JSON Error \(parseError.localizedDescription)")
        handler(nil)
     }
   }

   task.resume()
}

如果您的json如下所示：

[
{
    "mass_description": "Blah1", 
    "mass_date": "5/1/2019", 
    "mass_location": "", 
    "mass_time": "7:30 PM", 
    "mass_id": 7780
}, 
{
    "mass_description": "blah2", 
    "mass_date": "6/10/2019", 
    "mass_location": "1234 some place Los Angeles", 
    "mass_time": "7:30 PM", 
    "mass_id": 7781
}, 
{
    "mass_description": "blah3", 
    "mass_date": "5/21/2019", 
    "mass_location": "", 
    "mass_time": "7:30 PM", 
    "mass_id": 7783
}, 
{
    "mass_description": "blah4", 
    "mass_date": "4/5/2019", 
    "mass_location": "4050 Mission Ave, Oceanside, CA 92057", 
    "mass_time": "2:30 PM", 
    "mass_id": 1115
}
]

您可以很容易地解码：

let items = try JSONDecoder().decode([MassInfoObject].self, data)

---

您试图解析的json没有非常合理的结构。如果您可以控制json，那么应该首先处理它。如果您没有控制权，我建议在解析之前在客户端转换json

在操场上进行以下工作：

let str = """
{ "mass_info1": [{ "mass_id":7780, "mass_date":"5/1/2019", "mass_time":"7:30 PM", "mass_location":"", "mass_description": "Blah1"
} ] ,
"mass_info2":  [ { "mass_id":7781,  "mass_date":"6/10/2019", "mass_time":"7:30 PM", "mass_location":"1234 some place Los Angeles",  "mass_description": "Blah2"
} ] ,
"mass_info3":
[ { "mass_id":7783,  "mass_date":"5/21/2019",  "mass_time":"7:30 PM",  "mass_location":"",  "mass_description": "blah3"
} ] ,
"mass_info4":
[ { "mass_id":1115,  "mass_date":"4/5/2019", "mass_time":"2:30 PM", "mass_location":"4050 Mission Ave, Oceanside, CA 92057",  "mass_description": "blah4"
} ]
}
"""

struct MassInfoObject: Codable {
    var mass_id: Int
    var mass_date: String?
    var mass_time: String?
    var mass_location: String?
    var mass_description: String?
}

let data = str.data(using: .utf8)!

let json = try JSONSerialization.jsonObject(with: data, options: []) as? [String: [[String: Any]]]

let jsonArray = json!.values.map { $0 }

let cleanedJson = try JSONSerialization.data(withJSONObject: jsonArray, options: [])

let decoder = JSONDecoder()
let items = try decoder.decode([[MassInfoObject]].self, from: cleanedJson)

第一步是将json转换为易于解析的内容。因为现在MassInfoObject符合

Codable

，所以可以使用一个简单的JSONDecoder来解码对象数组，这只是一行代码

另外，在您的网络代码中，您正在调用一个异步任务，但是您的任务将立即返回，这是行不通的。从

getJson

函数返回时，还没有结果。最简单的方法是使用一个可以调用结果的闭包：

在您的网络代码中，它看起来是这样的：

func getjson(handler: @escaping ([MassInfoObject]?)->()) {
  let urlPath = "http://myclassinfo.com/dev/json.php"
  let url = URL(string: urlPath)
  let task = URLSession.shared.dataTask(with: url!) { data, response, error in
     print("Task completed")

     guard let data = data && error == nil else {
        //print(error?.localizedDescription)
        return
     }
     do {
        let json = try JSONSerialization.jsonObject(with: data, options: []) as? [String: [[String: Any]]]
        let jsonArray = json!.values.map { $0 }
        let cleanedJson = try JSONSerialization.data(withJSONObject: jsonArray, options: [])
        let decoder = JSONDecoder()
        let items = try decoder.decode([[MassInfoObject]].self, from: cleanedJson).compactMap { $0 }

        handler(items)

     } catch let parseError as NSError {
        print("JSON Error \(parseError.localizedDescription)")
        handler(nil)
     }
   }

   task.resume()
}

如果您的json如下所示：

[
{
    "mass_description": "Blah1", 
    "mass_date": "5/1/2019", 
    "mass_location": "", 
    "mass_time": "7:30 PM", 
    "mass_id": 7780
}, 
{
    "mass_description": "blah2", 
    "mass_date": "6/10/2019", 
    "mass_location": "1234 some place Los Angeles", 
    "mass_time": "7:30 PM", 
    "mass_id": 7781
}, 
{
    "mass_description": "blah3", 
    "mass_date": "5/21/2019", 
    "mass_location": "", 
    "mass_time": "7:30 PM", 
    "mass_id": 7783
}, 
{
    "mass_description": "blah4", 
    "mass_date": "4/5/2019", 
    "mass_location": "4050 Mission Ave, Oceanside, CA 92057", 
    "mass_time": "2:30 PM", 
    "mass_id": 1115
}
]

您可以很容易地解码：

let items = try JSONDecoder().decode([MassInfoObject].self, data)

---

谢谢马塞尔和所有帮助我的人。这是我使用的代码

struct MassObj:Decodable{
    var mass_id:Int
    var mass_date: String
    var mass_time:String
    var mass_location:String
    var mass_description:String
}

func getJsonArray2() {

        let urlPath = "http://myclassinfo.com/dev/json.php"
        guard let url = URL(string: urlPath) else {return }
        let task = URLSession.shared.dataTask(with: url)
        {
            data, response, error in
            print("Task completed")

            guard data != nil && error == nil else {
                //print(error?.localizedDescription)
                return
            }
            do{
                var massArray = [MassObj]()
                massArray = try JSONDecoder().decode([MassObj].self, from:data!)

                for object in massArray {
                    print("\(object.mass_id) == \(object.mass_date) == \(object.mass_description)")
                }

            }catch let jerr {
                print(jerr)
            }

        }

        task.resume()
    }

================ json是

[
{
    "mass_description": "Blah1", 
    "mass_date": "5/1/2019", 
    "mass_location": "", 
    "mass_time": "7:30 PM", 
    "mass_id": 7780
}, 
{
    "mass_description": "blah2", 
    "mass_date": "6/10/2019", 
    "mass_location": "1234 some place Los Angeles", 
    "mass_time": "7:30 PM", 
    "mass_id": 7781
}, 
{
    "mass_description": "blah3", 
    "mass_date": "5/21/2019", 
    "mass_location": "", 
    "mass_time": "7:30 PM", 
    "mass_id": 7783
}, 
{
    "mass_description": "blah4", 
    "mass_date": "4/5/2019", 
    "mass_location": "4050 Mission Ave, Oceanside, CA 92057", 
    "mass_time": "2:30 PM", 
    "mass_id": 1115
}
]

---

谢谢马塞尔和所有帮助我的人。这是我使用的代码

struct MassObj:Decodable{
    var mass_id:Int
    var mass_date: String
    var mass_time:String
    var mass_location:String
    var mass_description:String
}

func getJsonArray2() {

        let urlPath = "http://myclassinfo.com/dev/json.php"
        guard let url = URL(string: urlPath) else {return }
        let task = URLSession.shared.dataTask(with: url)
        {
            data, response, error in
            print("Task completed")

            guard data != nil && error == nil else {
                //print(error?.localizedDescription)
                return
            }
            do{
                var massArray = [MassObj]()
                massArray = try JSONDecoder().decode([MassObj].self, from:data!)

                for object in massArray {
                    print("\(object.mass_id) == \(object.mass_date) == \(object.mass_description)")
                }

            }catch let jerr {
                print(jerr)
            }

        }

        task.resume()
    }

================ json是

[
{
    "mass_description": "Blah1", 
    "mass_date": "5/1/2019", 
    "mass_location": "", 
    "mass_time": "7:30 PM", 
    "mass_id": 7780
}, 
{
    "mass_description": "blah2", 
    "mass_date": "6/10/2019", 
    "mass_location": "1234 some place Los Angeles", 
    "mass_time": "7:30 PM", 
    "mass_id": 7781
}, 
{
    "mass_description": "blah3", 
    "mass_date": "5/21/2019", 
    "mass_location": "", 
    "mass_time": "7:30 PM", 
    "mass_id": 7783
}, 
{
    "mass_description": "blah4", 
    "mass_date": "4/5/2019", 
    "mass_location": "4050 Mission Ave, Oceanside, CA 92057", 
    "mass_time": "2:30 PM", 
    "mass_id": 1115
}
]

---

您的JSON组织得非常糟糕。为什么要有一个顶级字典，其中每个键的值都是一个数组，其中有一个字典？您应该在顶部有一个数组，其中只包含字典列表。您的JSON组织得非常糟糕。为什么要有一个顶级字典，其中每个键的值都是一个数组，其中有一个字典？您应该在顶部有一个数组，其中只包含字典列表。感谢Marcel，我在行处理程序（项）上有编译错误。错误消息是无法将“[[MassInfoObject]]”类型的值转换为预期的参数类型“[MassInfoObject]”。我应该有处理程序。追加（项）我更新了代码，仍然需要平坦响应。目前它还不是很优雅（就像在，一点也不）。如果你能控制json格式，那就更好了。谢谢Marcel，如果你想更改json，你会更改什么？@JohnMiky，因为你肯定知道json是大量的，我建议删除冗余信息，例如

“description:”Blah1”，“date:”2019年5月1日”，“location:”，“time:“7:30 PM”，“id”：7780}，

。然后可以声明符合命名约定的结构成员，去掉下划线字符。感谢Marcel，Vadian我更改了json并使用了

let items=try JSONDecoder（）.decode（[MassInfoObject].self，data）

它工作得非常好。感谢您的帮助谢谢Marcel，我在行处理程序（项）上有编译错误错误错误消息是无法将“[[MassInfoObject]]”类型的值转换为预期的参数类型“[MassInfoObject]”？我是否应该有处理程序。追加（项）我更新了代码，仍然需要平坦响应。目前它还不是很优雅（就像在，一点也不）。如果你能控制json格式，那就更好了。谢谢Marcel，如果你想更改json，你会更改什么？@JohnMiky，因为你肯定知道json是大量的，我建议删除冗余信息，例如

“description:”Blah1”，“date:”2019年5月1日”，“location:”，“time:“7:30 PM”，“id”：7780}，

。然后可以声明符合命名约定的结构成员，去掉下划线字符。感谢Marcel，Vadian我更改了json并使用了

let items=try JSONDecoder（）.decode（[MassInfoObject].self，data）

它工作得非常好。谢谢你的帮助