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在Swift中解码json对象

swift

-1

casillas · 技术社区 · 6 年前

我有一个json文件,读取并解码如下。我的json文件如下所示,A和B代表struct对象。我想知道有没有更好、更有效的方法来解码这种类型的json?

[ 
 [
   {"id": "152478", "age": "20"},{"character": "king", "isDead":"no", "canMove" :"yes"}
 ],
 [
  {"id": "887541", "age": "22"},{"character": "lion", "isDead":"no", "canMove" :"yes"}
 ]
]

解码如下:

    let url = Bundle.main.url(forResource: "mypew", withExtension: "json")!
        do {

        let jsonData = try Data(contentsOf: url)

         // B -> json[0][0], [1][0]
         // A -> json[0][1], [0][1]

        response = try JSONSerialization.jsonObject(with: jsonData) as! [[[String: Any]]]
        for i in 0..<response.count
        {
            for j in 0..<response[i].count
            {
                if j == 0
                {
                    let jsonDat = (try? JSONSerialization.data(withJSONObject:response[i][j]))!
                    let bElement = try JSONDecoder().decode(B.self, from: jsonDat)
                    self.bArray.append(bElement)
                }
                else if j == 1
                {
                    let jsonDatt = (try? JSONSerialization.data(withJSONObject:response[i][j]))!
                    let aElement = try JSONDecoder().decode(A.self, from: jsonDatt)
                    self.aArray.append(aElement)
                }
            }
        }

1 回复 | 直到 6 年前

New Dev 6 年前

首先,制作两个对象(我们称之为 A 和 B )符合 Decodable :

struct A: Decodable {
    var id, age: String
}

struct B: Decodable {
    var character, isDead, canMove: String
}

那么,如果你的结构为 A. 和 B 都是一样的,也就是说 [A, B] ,然后你可以把这对解码成它自己的对象。我们称之为物体 ABPair :

struct ABPair: Decodable {
  let a: A
  let b: B

  init(from decoder: Decoder) throws {
    var container = try decoder.unkeyedContainer()

    guard let a = try? container.decode(A.self), 
          let b = try? container.decode(B.self) 
      else {
        // throw since we didn't find A first, followed by B
        throw DecodingError.dataCorruptedError(in: container, debugDescription: "error")
      }

    self.a = a
    self.b = b
  }
}

您可以按如下方式解码成对数组:

let decoder = JSONDecoder()
let pairs = try? decoder.decode([ABPair].self, from: jsonData)

print(pairs[1].b.character) // lion

-2

Frankenstein 6 年前

首先,你需要创建一个 Codable 模型的结构。然后从数据而不是JSON对象解码模型。这里是代码,

型号:

struct Model: Codable {
    let id, age, character, isDead, canMove: String?
}

解码:

let url = Bundle.main.url(forResource: "mypew", withExtension: "json")!
do {
    let jsonData = try Data(contentsOf: url)
    let models = try JSONDecoder().decode([[Model]].self, from: jsonData)
    for model in models {
        print(model[0].age, model[1].canMove)
    }
} catch {
    print(error)
}