json - 从 Core Data 获取 JSON 格式的特定项目

Question

我有一个核心数据实体 Checkout，它只有一个可转换的属性并设置为 [String:Any]:

cart : [String:Any]

现在我使用此函数来检索购物车中的商品:

 func getCheckOutItems()->  [NSDictionary]{
    let request : NSFetchRequest<Checkout> = Checkout.fetchRequest()
    request.propertiesToFetch = ["cart"]
    request.resultType = .dictionaryResultType
    var checkout : [NSDictionary]!
    var cart : [String:Any]!
    do{
        checkout = try context.fetch(request)
    }catch{
        print ("Error fetching data")
    }
    return checkout
}

现在我需要将这些项目添加到字典中，该字典还包含其他类似这样的项目:

 var cart = [String:Any]()
    cart["cart"] = getCheckOutItems()
    cart["telco"] = "something"
    cart["fcm_token"] = "tokden"
    cart["email"] = "email"
    let jsonData = try? JSONSerialization.data(withJSONObject: cart, options: [])
    let jsonString = String(data: jsonData!, encoding: .utf8)
    print("Printing JSON \(jsonString)")

这是为了产生这样的 json 结果:

{
"fcm_token": "tokden",
"cart": [{
        "entity": 1,
        "quantity": 1,
        "id": 428,
        "price": 80,
        "date": "30 Jan 2018",
        "seat_no": 20,
        "type": "bus",
        "item": "STANDARD",
        "schedule_id": 132
    },
    {
        "entity": 1,
        "quantity": 1,
        "id": 1539,
        "price": 110,
        "date": "30 Jan 2018",
        "seat_no": 7,
        "type": "bus",
        "item": "EXECUTIVE",
        "schedule_id": 131
    },
    {
        "entity": 1,
        "quantity": 1,
        "id": 282,
        "price": 40,
        "date": "30 Jan 2018",
        "seat_no": 1,
        "type": "bus",
        "item": "STANDARD",
        "schedule_id": 114
    }
],
"telco": "something",
"email": "email"

}

主要目的是确保当购物车项目附加到最终 json 结果时，它们附加为带有键“cart”的数组。但是，由于我无法循环获取每个商品购物车，因此当我将其添加到 JSON 时，我得到的结果如下:

{
"fcm_token": "tokden",
"cart": [{
    **"cart": {**
        "entity": 1,
        "quantity": 1,
        "id": 428,
        "price": 80,
        "date": "30 Jan 2018",
        "seat_no": 20,
        "type": "bus",
        "item": "STANDARD",
        "schedule_id": 132
    }
}, {
    "cart": {
        "entity": 1,
        "quantity": 1,
        "id": 1539,
        "price": 110,
        "date": "30 Jan 2018",
        "seat_no": 7,
        "type": "bus",
        "item": "EXECUTIVE",
        "schedule_id": 131
    }
}, {
    "cart": {
        "entity": 1,
        "quantity": 1,
        "id": 282,
        "price": 40,
        "date": "30 Jan 2018",
        "seat_no": 1,
        "type": "bus",
        "item": "STANDARD",
        "schedule_id": 114
    }
}],
"telco": "something",
"email": "email"

}

如何格式化此结果，以便消除“cart”键以格式化 json，如前所述

Answer 1

您可以使用此库将 json 保存到 coredata，反之亦然。

Click this link for the library 3Lvis Library