Question

使用以下代码，我可以有效地获取JSON对象，但不确定如何从对象中检索特定属性。

快捷代码

@IBAction func testing(_ sender: Any) {
    let url = URL(string: "http://example.com/cars/mustang")

    let task = URLSession.shared.dataTask(with: url!) { data, response, error in
        guard error == nil else {
            print(error!)
            return
        }
        guard let data = data else {
            print("Data is empty")
            return
        }
        let json = try! JSONSerialization.jsonObject(with: data, options: [])
        print(json)
    }
    task.resume()
}

当我运行上面的代码时，这就是我看到的...

输出-JSON对象

(
    {
    color = "red";
    engine = "5.0";
    }
)

如何仅获取属性颜色？

谢谢

Answer 1

创建一个确认可解码协议的类；以您的情况为例的CarInfo

class CarInfo: Decodable

创建类的属性

var color: String

var engine: String

创建从CodingKey继承的JSON密钥枚举

enum CarInfoCodingKey: String, CodingKey {
   case color 
   case engine 
}

实现初始化

required init(from decoder: Decoder) throws

班级将是

class CarInfo: Decodable {
var color: String
var engine: String
enum CarInfoCodingKey: String, CodingKey {
case color
case engine
}
public init(from decoder: Decodabler) throws {
let container = try decoder.container(keyedBy: CarInfoCodingKey.self)
self.color = try container.decode(String.self, forKey: .color)
self.engine = try contaire.decode(String.self, forKey: .engine)
}
}

通话解码器

let carinfo = try JsonDecoder().decode(CarInfo.self, from: jsonData)

Answer 2

这是我的方法...

@IBAction func testing(_ sender: Any) {
    let url = URL(string: "http://example.com/cars/mustang")

    let task = URLSession.shared.dataTask(with: url!) { data, response, error in
        guard error == nil else {
            print(error!)
            return
        }
        guard let data = data else {
            print("Data is empty")
            return
        }
        let json = try! JSONSerialization.jsonObject(with: data, options: [])

        guard let jsonArray = json as? [[String: String]] else {
            return
        }
        let mustangColor = jsonArray[0]["color"]

        print(mustangColor!)
    }
    task.resume()
}

如何使用URLSession从HTTP请求的JSON对象获取特定属性

快捷代码

输出-JSON对象

2 个答案: