“[Root]”类型的值没有成员“commit”。我如何解码 JSON 根数组

Posted 2023-03-15

【中文标题】“[Root]”类型的值没有成员“commit”。我如何解码 JSON 根数组

【英文标题】：Value of type '[Root]' has no member 'commit'. How can i decode JSON root array

【发布时间】：2018-08-12 10:36:45

【问题描述】：

我正在尝试使用可编码解析 JSON。我能够对其进行解码，但它位于根数组中，我无法自行打印每个值。编译器抱怨说Value of type '[Root]' has no member 'commit'。我如何更改它以打印值。下面是 JSON

[
    
        "sha": "3f4227ec2894bb354b145deff9dbc1adc6b6d6f2",
        "node_id": "MDY6Q29tbWl0NDQ4Mzg5NDk6M2Y0MjI3ZWMyODk0YmIzNTRiMTQ1ZGVmZjlkYmMxYWRjNmI2ZDZmMg==",
        "commit": 
            "author": 
                "name": "Slava Pestov",
                "email": "[e-mail]",
                "date": "2018-08-12T08:09:22Z"
            
        
    ,
    
        "sha": "3f4227ec2894bb354b145deff9dbc1adc6b6d6f2",
        "node_id": "MDY6Q29tbWl0NDQ4Mzg5NDk6M2Y0MjI3ZWMyODk0YmIzNTRiMTQ1ZGVmZjlkYmMxYWRjNmI2ZDZmMg==",
        "commit": 
            "author": 
                "name": "Slava Pestov",
                "email": "[e-mail]",
                "date": "2018-08-12T08:09:22Z"
            
        
    
]

我在这里解码

struct Root: Decodable 
    let commit: Author


struct Author: Decodable 
    let author: People


struct People: Decodable 
    let name: String?
    let date: String?
    let email: String?


class ViewController: UIViewController 

    override func viewDidLoad() 
        super.viewDidLoad()
        getCommits()
    


    func getCommits() 
        let urlString = "https://api.github.com/repos/apple/swift/commits"
        guard let url = URL(string: urlString) else 
            print("Couldn't fetch JSON")
            return
        
        let session = URLSession.shared
        let dataTask = session.dataTask(with: url)  (data, response, error) in
            guard data != nil && error == nil else 
                print(data ?? "")
                return
            
            do 
                let decoder = JSONDecoder()
                let result = try decoder.decode([Root].self, from: data!)
                print(result.commit)
                print(result.commit.author.name)
             catch let decodeError 
                print("Failed to decode json:", decodeError)
            
        
        dataTask.resume()
    

这是我在控制台中的输出。我希望能够只打印姓名、日期和电子邮件。

[Gihhub.Commits(commit: Gihhub.Author(author: Gihhub.People(name: Optional("Slava Pestov"), date: Optional("2018-08-12T08:09:22Z")), email: Optional （“[e-mail]”）））），Gihhub.Commits（提交：Gihhub.Author（作者：Gihhub.People（名称：可选（“Slava Pestov”），日期：可选（“2018-08- 12T03:47:22Z")，电子邮件：可选（“[e-mail]”）））），Gihhub.Commits（提交：Gihhub.Author（作者：Gihhub.People（名称：可选（“Slava Pestov”）），日期：可选（“2018-08-12T03:47:08Z”），电子邮件：可选（“[e-mail]”））））]

【问题讨论】：

结构的命名有点混乱。应该是struct Root: Decodable let commit: Commit struct Commit: Decodable let author: Author struct Author: Decodable let name: String; let date: String; let email: String 。所有结构成员都可以是非可选的。如果添加日期解码策略.iso8601，则可以将date解码为Date

PS：请从24:00开始观看WWDC 2017 Session 212 : What's new in Foundation。你会看到非常熟悉的东西。

@vadian 非常感谢你，我已经看过并改进了我的代码。干杯

【参考方案1】：

结果是你需要的数组

result.forEach 
    print($0.commit.author.name)
    print($0.commit.author.date)
    print($0.commit.author.email)

【讨论】：

非常感谢。忘记循环了。效果很好。