使用Codable解码JSON

Question

我有以下JSON字符串要解码：

{
"albums": {
    "album": [
        {
            "name": "Dark & Wild",
            "mbid": "",
            "url": "https://www.last.fm/music/BTS",
            "artist": {
                "name": "BTS",
                "mbid": "0d79fe8e-ba27-4859-bb8c-2f255f346853",
                "url": "https://www.last.fm/music/BTS"
            },
            "image": [
                {
                    "#text": "https://lastfm.freetls.fastly.net/i/u/34s/6dfcd9efe7f9560334eadaf3ad6a0049.png",
                    "size": "small"
                },
                {
                    "#text": "https://lastfm.freetls.fastly.net/i/u/64s/6dfcd9efe7f9560334eadaf3ad6a0049.png",
                    "size": "medium"
                },
                {
                    "#text": "https://lastfm.freetls.fastly.net/i/u/174s/6dfcd9efe7f9560334eadaf3ad6a0049.png",
                    "size": "large"
                },
                {
                    "#text": "https://lastfm.freetls.fastly.net/i/u/300x300/6dfcd9efe7f9560334eadaf3ad6a0049.png",
                    "size": "extralarge"
                }
            ],
            "@attr": {
                "rank": "1"
            }
        },
        {
            "name": "Agust D",
            "mbid": "",
            "url": "https://www.last.fm/music/Agust+D",
            "artist": {
                "name": "Agust D",
                "mbid": "",
                "url": "https://www.last.fm/music/Agust+D"
            },
            "image": [
                {
                    "#text": "https://lastfm.freetls.fastly.net/i/u/34s/05ed3fae3b45b2fcda6c80e76c4c8aed.png",
                    "size": "small"
                },
                {
                    "#text": "https://lastfm.freetls.fastly.net/i/u/64s/05ed3fae3b45b2fcda6c80e76c4c8aed.png",
                    "size": "medium"
                },
                {
                    "#text": "https://lastfm.freetls.fastly.net/i/u/174s/05ed3fae3b45b2fcda6c80e76c4c8aed.png",
                    "size": "large"
                },
                {
                    "#text": "https://lastfm.freetls.fastly.net/i/u/300x300/05ed3fae3b45b2fcda6c80e76c4c8aed.png",
                    "size": "extralarge"
                }
            ],
            "@attr": {
                "rank": "2"
            }
        }
    ],
    "@attr": {
        "tag": "Hip Hop",
        "page": "1",
        "perPage": "2",
        "totalPages": "6491",
        "total": "12982"
    }
}

我实现了以下Codable结构：

struct Root: Codable {
    var albums: [Album]
}

struct Album: Codable {
    var name: String
    var mbid: String
    var url: String
    var image: AlbumImage
    var artist: AlbumArtist
}

struct AlbumImage: Codable {
    var text: String
    var size: String
}

struct AlbumArtist: Codable {
    var name: String
    var mbid: String
    var url: String
}

然后，当我尝试使用以下函数解码JSON Data时：

func parse(json: Data) {
    let decoder = JSONDecoder()
    
    do {
        let root = try decoder.decode(Root.self, from: json)
        print("root", root.albums)
        
    } catch {
        print("Failed to decode:", error)
    }        
}

调试器抛出以下错误：

Failed to decode: typeMismatch(Swift.Array<Any>, Swift.DecodingError.Context(codingPath: [CodingKeys(stringValue: "albums", intValue: nil)], debugDescription: "Expected to decode Array<Any> but found a dictionary instead.", underlyingError: nil))

有人能帮我解决这个问题吗？我是错误地实现了Codable结构，还是错误地解析了它？谢谢。

Answer 1

在这里，您遗漏了一个顶级属性，即"Albums“。根类有一个字典类型的属性"albums“，然后该类包含数组属性，如下所示：-

struct Root: Codable {
    let albums: Albums
}

// MARK: - Albums
struct Albums: Codable {
    let album: [Album]
    let attr: AlbumsAttr

    enum CodingKeys: String, CodingKey {
        case album
        case attr = "@attr"
    }
}

Answer 2

正如我所看到的，您已经将图像类型指定为AlbumImage，但它期望的是AlbumImage而不是单个元素，请尝试更改模型的图像属性，如下所示

var镜像: AlbumImage