[英]How to parse nested json? Swift
我有一個本地 json 字符串,我正在嘗試解析它,但是當我嘗試這樣做時,我不斷收到錯誤消息。 我也在嵌套字典中看到了這個錯誤,但找不到錯誤。 下面是json字符串
let jsonNestedString = "{\"meta\":{\"page\":1,\"total_pages\":4,\"per_page\":10,\"total_records\" : 38}, \"reweries\":[\"id\":1234,\"name\":\"saintArnold\"},{\"id\":52892,\"name\":\"buffalo bayou\"]}"
我正在通過 Codable 執行此過程,下面是我為此創建的結構
struct PagedBreweries:Codable{
struct Meta:Codable{
let page : Int
let total_pages:Int
let per_page:Int
let total_records: Int
enum CodingKeys: String, CodingKey{
case page
case total_pages
case per_page
case total_records
}
}
struct Brewery :Codable{
let id:Int
let name:String
}
let meta:Meta
let breweries :[Brewery]
}
然后將此數據解析為如下函數
func jsonNested(){
let jsonData = jsonNestedString.data(using: .utf8)
let decoder = JSONDecoder()
let data = try! decoder.decode(PagedBreweries.Meta.self, from: jsonData!)
print(data)
}
當我嘗試構建時,我得到的錯誤出現在嘗試中! 解碼器.解碼
命令,錯誤是
線程 1:致命錯誤:“嘗試!” 表達式意外引發錯誤:Swift.DecodingError.keyNotFound(CodingKeys(stringValue: "page", intValue: nil), Swift.DecodingError.Context(codingPath: [], debugDescription: "No value associated with key CodingKeys(stringValue: \\") page\\", intValue: nil) (\\"page\\").",underlyingError: nil))
任何人都可以提供解決方案嗎? 提前致謝
正確的json
{
"meta": {
"page": 1,
"total_pages": 4,
"per_page": 10,
"total_records": 38
},
"reweries": [{
"id": 1234,
"name": "saintArnold"
},
{
"id": 52892,
"name": "buffalo bayou"
}
]
}
struct Root: Codable {
let meta: Meta
let reweries: [Rewery]
}
struct Meta: Codable {
let page, totalPages, perPage, totalRecords: Int
enum CodingKeys: String, CodingKey { // snake case may be used
case age = "page"
case totalPages = "total_pages"
case perPage = "per_page"
case totalRecords = "total_records"
}
}
struct Rewery: Codable {
let id: Int
let name: String
}
let jsonNestedString = """
{\"meta\":{\"page\":1,\"total_pages\":4,\"per_page\":10,\"total_records\":38}, \"reweries\":[{\"id\":1234,\"name\":\"saintArnold\"},{\"id\":52892,\"name\":\"buffalo bayou\"}]}
"""
// or
let jsonNestedString = """
{
"meta": {
"page": 1,
"total_pages": 4,
"per_page": 10,
"total_records": 38
},
"reweries": [{
"id": 1234,
"name": "saintArnold"
},
{
"id": 52892,
"name": "buffalo bayou"
}
]
}
"""
do {
let jsonData = jsonNestedString.data(using: .utf8)
let decoder = JSONDecoder()
let data = try decoder.decode(Root.self, from: jsonData!)
print(data)
} catch {
print(error)
}
JSON 已損壞,您正在解碼錯誤的根對象。
這是使用您的結構解碼並符合 Swift 命名約定的正確JSON
let jsonNestedString = """
{"meta":{"page":1,"total_pages":4,"per_page":10,"total_records" : 38}, "breweries":[{"id":1234,"name":"saintArnold"},{"id":52892,"name":"buffalo bayou"}]}
"""
struct PagedBreweries : Codable {
struct Meta : Codable {
let page : Int
let totalPages:Int
let perPage:Int
let totalRecords: Int
}
struct Brewery : Codable {
let id:Int
let name:String
}
let meta:Meta
let breweries :[Brewery]
}
func jsonNested(){
let jsonData = Data(jsonNestedString.utf8)
let decoder = JSONDecoder()
decoder.keyDecodingStrategy = .convertFromSnakeCase
let data = try! decoder.decode(PagedBreweries.self, from: jsonData)
print(data)
}
jsonNested()
// Printed result:
// PagedBreweries(meta: __lldb_expr_1.PagedBreweries.Meta(page: 1, totalPages: 4, perPage: 10, totalRecords: 38), breweries: [__lldb_expr_1.PagedBreweries.Brewery(id: 1234, name: "saintArnold"), __lldb_expr_1.PagedBreweries.Brewery(id: 52892, name: "buffalo bayou")])
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