我想解析一個大的JSON字符串,我從URL中檢索。我使用的測試JSON低於:在Swift中使用Decodable和CodingKeys解析JSON 4
let json = """
{
"feed": {
"title": "Harry Potter",
"test": "I dont want this value",
"results": [
{
"author": "JK Rowling",
"artworkURL": "A url",
"genres": [
{
"name": "Fantasy"
},
{
"name": "Scifi"
}
],
"name": "Goblet of Fire",
"releaseDate": "2000-07-08"
},
{
"author": "JK Rowling",
"artworkURL": "A url",
"genres": [
{
"name": "Fantasy"
},
{
"name": "Scifi"
}
],
"name": "Half Blood Prince",
"releaseDate": "2009-07-15"
}
]
}
}
""".data(using: .utf8)!
我有幾個數據結構的數據放置到:
struct Genre: Decodable {
let name: String
}
struct Book: Decodable {
let author: String
let artworkURL: URL
let genres: [Genre]
let name: String
let releaseDate: String
}
struct BookCollection {
let title: String
let books: [Book]
enum CodingKeys: String, CodingKey {
case feed
}
enum FeedKeys: String, CodingKey {
case title, results
}
enum ResultKeys: String, CodingKey {
case author, artworkURL, genres, name, releaseDate
}
enum GenreKeys: String, CodingKey {
case name
}
}
extension BookCollection: Decodable {
init(from decoder: Decoder) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
let feed = try values.nestedContainer(keyedBy: FeedKeys.self,
forKey: .feed)
self.title = try feed.decode(String.self, forKey: .title)
self.books = try feed.decode([Track].self, forKey: .results)
}
}
我然後打印過的資料,像這樣:
do {
let response = try JSONDecoder().decode(BookCollection.self, from: json)
for book in response.books {
print(book.genres)
}
} catch {
print(error)
}
它成功地打印除流派外的所有信息。這給我一個流派,但我不能做 book.genres.name
訪問名稱。我必須使用: book.genres[0]
它給我的結果只是第一個索引。
有沒有一種方法可以在我的BookCollection
擴展中完善我的JSON解碼,然後利用book.genres.name
?
謝謝
要清楚,'book.genres.name'應該返回什麼值? –
@PauloMattos它應該爲每本書返回一個數組。第一本書是「幻想」和「科幻」。 –
@DominicPilla你可以添加一個只讀的計算屬性到你的Book結構'擴展書籍'var allGenres:[String] { return genres.map {$ 0.name} } }'並使用print(book.allGenres )' –