Swift 可解码可选密钥

Swift 可解码可选密钥的重要性

swift
struct User: Codable {
    let name: String
    let age: Int
    let email: String
    let address: String
    private enum CodingKeys: String, CodingKey {
        case name, age, email, address
    }
    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        name = try container.decode(String.self, forKey: .name)
        age = try container.decode(Int.self, forKey: .age)
        email = try container.decode(String.self, forKey: .email)
        address = try container.decode(String.self, forKey: .address)
    }
    func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(name, forKey: .name)
        try container.encode(age, forKey: .age)
        try container.encode(email, forKey: .email)
        try container.encode(address, forKey: .address)
    }
}
let json = """
{
    "name": "John Doe",
    "age": 30,
    "email": "johndoe@example.com",
    "address": "123 Main Street"
}
"""
// 使用密钥解码数据
let decoderWithKey = JSONDecoder()
let userWithKey = try decoderWithKey.decode(User.self, from: json.data(using: .utf8)!)
// 不使用密钥解码数据
let decoderWithoutKey = JSONDecoder()
let userWithoutKey = try decoderWithoutKey.decode(User.self, from: json.data(using: .utf8)!)