使用Swift

Question

我在使用Swift 4解码这个JSON时遇到了很多麻烦。

{
    "Items": [
        {
            "id": 1525680450507,
            "animal": "bee",
            "type": "insect",
            "diet": [
                "a",
                "b",
                "c"
            ]
        }
    ],
    "Count": 1,
    "ScannedCount": 5
}

这是我尝试解码的地方

let decoder = JSONDecoder()
let data = try decoder.decode([Animal].self, from: data)

我创建了一个像这样的结构

struct Animal: Codable {
    var id: Int
    var animal: String
    var type: String
    var diet: [String]
}

let decoder = JSONDecoder()
let data = try decoder.decode(ItemsResponse.self, from: data)

这不起作用。我收到一条错误

  

＆＃34;预计解码数组＆lt; \ Any＆gt;但是找到了一本字典。＆＃34;

所以我想也许我需要这样的东西

struct ItemsResponse: Codable {
    var Items: [Animal]
    var Count: Int
    var ScannedCount: Int
}

但这也不起作用。现在我得到

  

＆＃34;预计解码数组＆lt; \ Any＆gt;但是找到了一个字符串/数据。＆＃34;

如何创建一个解码此JSON的结构？

Answer 1

let data = try decoder.decode([Animal].self, from: data)

[Animal].self不正确你可以像这样使用它：

struct DataJson: Codable {
    let items: [Item]
    let count, scannedCount: Int

    enum CodingKeys: String, CodingKey {
        case items = "Items"
        case count = "Count"
        case scannedCount = "ScannedCount"
    }
}

struct Item: Codable {
    let id: Int
    let animal, type: String
    let diet: [String]
}

// MARK: Convenience initializers

extension DataJson {
    init(data: Data) throws {
        self = try JSONDecoder().decode(DataJson.self, from: data)
    }



    func jsonData() throws -> Data {
        return try JSONEncoder().encode(self)
    }

    func jsonString(encoding: String.Encoding = .utf8) throws -> String? {
        return String(data: try self.jsonData(), encoding: encoding)
    }
}

extension Item {
    init(data: Data) throws {
        self = try JSONDecoder().decode(Item.self, from: data)
    }


    func jsonData() throws -> Data {
        return try JSONEncoder().encode(self)
    }

    func jsonString(encoding: String.Encoding = .utf8) throws -> String? {
        return String(data: try self.jsonData(), encoding: encoding)
    }
}

Answer 2

试试这个：

import Foundation

let json = """
{
    "Items": [
        {
            "id": 1525680450507,
            "animal": "bee",
            "type": "insect",
            "diet": [
                "a",
                "b",
                "c"
            ]
        }
    ],
    "Count": 1,
    "ScannedCount": 5
}
"""

struct Animal: Codable {
    var id: Int
    var animal: String
    var type: String
    var diet: [String]
}

struct ItemsResponse: Codable {
    var Items: [Animal]
    var Count: Int
    var ScannedCount: Int
}

let data = try! JSONDecoder().decode(ItemsResponse.self, from: json.data(using: .utf8)!)

当然，您应该正确处理可能的失败（即不要执行try!，并且不要强行解开json.data()!部分）

但上面的代码有效，希望能回答你的问题。