Swift 4中Encodable JSON字典处理方法问询及解决方案分享

之前我碰到了在Swift 4里处理这段指定JSON数据并实现Encodable字典转换的问题，多亏@matt的帮忙才顺利解决！现在把完整的实现代码分享出来，给遇到同样需求的开发者做个参考～

原始JSON数据 #

首先是我们要处理的目标JSON：

{ 
  "restaurants": [ 
    { 
      "id": 1, 
      "restaurantName": "Chuks", 
      "restaurantPicture": "restaurantImages/benards.jpg", 
      "status": "Working", 
      "workingDays": "Tuesday to Sunday", 
      "workingHours": "3pm to 10pm" 
    }, 
    { 
      "id": 3, 
      "restaurantName": "Chuks", 
      "restaurantPicture": "restaurantImages/benards.jpg", 
      "status": "Working", 
      "workingDays": "Tuesday to Sunday", 
      "workingHours": "3pm to 10pm" 
    } 
  ]
}

实现Encodable模型 #

我们需要创建和JSON结构完全匹配的Encodable结构体，Swift 4的Encodable协议可以帮我们自动完成编码逻辑，不需要手动写转换代码：

// 单个餐厅的模型结构体
struct Restaurant: Encodable {
    let id: Int
    let restaurantName: String
    let restaurantPicture: String
    let status: String
    let workingDays: String
    let workingHours: String
}

// 包含餐厅数组的外层响应结构体
struct RestaurantsResponse: Encodable {
    let restaurants: [Restaurant]
}

转换为字典或JSON数据 #

1. 将模型转换为字典 #

如果需要把模型转换成[String: Any]类型的字典，可以通过JSONEncoder先编码成JSON数据，再用JSONSerialization解析成字典：

// 先构造示例模型数据
let restaurant1 = Restaurant(id: 1, 
                            restaurantName: "Chuks", 
                            restaurantPicture: "restaurantImages/benards.jpg", 
                            status: "Working", 
                            workingDays: "Tuesday to Sunday", 
                            workingHours: "3pm to 10pm")

let restaurant2 = Restaurant(id: 3, 
                            restaurantName: "Chuks", 
                            restaurantPicture: "restaurantImages/benards.jpg", 
                            status: "Working", 
                            workingDays: "Tuesday to Sunday", 
                            workingHours: "3pm to 10pm")

let response = RestaurantsResponse(restaurants: [restaurant1, restaurant2])

// 执行转换
do {
    let jsonData = try JSONEncoder().encode(response)
    if let jsonDict = try JSONSerialization.jsonObject(with: jsonData, options: []) as? [String: Any] {
        print("转换完成的字典：\(jsonDict)")
    }
} catch {
    print("编码失败，错误信息：\(error.localizedDescription)")
}

2. 直接获取JSON数据 #

如果只是需要JSON格式的数据（比如用于网络请求），可以直接使用JSONEncoder的编码结果：

do {
    let jsonData = try JSONEncoder().encode(response)
    // 可以将jsonData用于网络请求或者本地存储
    if let jsonString = String(data: jsonData, encoding: .utf8) {
        print("生成的JSON字符串：\(jsonString)")
    }
} catch {
    print("编码失败，错误信息：\(error.localizedDescription)")
}

内容的提问来源于stack exchange，提问作者Sam Banana