Question

我正在使用swift从JSON检索数据。我是JSON的新手。我不知道如何检索这个嵌套值。我之前的问题是Issue raised, while retriving datas from JSON by using swift。我澄清了。这对我来说是新的。我的JSON格式如下。请指导我。

JSON响应格式：

{

"salutation": {
                "id": 1,
                "salutation": "Mr"
                },
"firstName": "AAA",
"middleName": "BBB",
"lastName": "C",
"employeeId": "RD484",

"station": {
                "id": 86,
                "stationCode": null,
                "stationName": "DDD",
                "subDivision": null,
                "address": null
                },
"subDivsion": {
                "id": 11,
                "divisionCode": "11",
                "divisionDesc": "EEE",
                "division": null
                }
}

//我的尝试：

 var maindict = NSDictionary() //Global declaration

 var session = NSURLSession.sharedSession()

 //now create the NSMutableRequest object using the url object
 let request = NSMutableURLRequest(URL: url!)
 request.HTTPMethod = "POST" //set http method as POST

 var err: NSError?
 request.HTTPBody = NSJSONSerialization.dataWithJSONObject(parameters, options: nil, error: &err) // pass dictionary to nsdata object and set it as request body

  request.addValue("application/json", forHTTPHeaderField: "Content-Type")
  request.addValue("application/json", forHTTPHeaderField: "Accept")
  var task = session.dataTaskWithRequest(request, completionHandler: {data, response, error -> Void in
  println("Response: \(response)")
  self.maindict = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil) as [String: AnyObject]
  var err: NSError?
  var json = NSJSONSerialization.JSONObjectWithData(data, options: .MutableLeaves, error: &err) as? NSDictionary

  // Did the JSONObjectWithData constructor return an error? If so, log the error to the console
  if(err != nil) {
  println(err!.localizedDescription)
  let jsonStr = NSString(data: data, encoding: NSUTF8StringEncoding)
  //println("Error could not parse JSON: '\(jsonStr)'")
  }
  else {
  // The JSONObjectWithData constructor didn't return an error. But, we should still
  // check and make sure that json has a value using optional binding.
  if let parseJSON = json {

  // Okay, the parsedJSON is here, let's get the value for 'success' out of it
  var success = parseJSON["success"] as? Int
  println("Succes: \(success)")

  self.dataFromJSON() //METHOD CALLING

  }
  else {
  // Woa, okay the json object was nil, something went worng. Maybe the server isn't running?
  let jsonStr = NSString(data: data, encoding: NSUTF8StringEncoding)
  println("Error could not parse JSON: \(jsonStr)")
  //println("AUTHENTICATION FAILED")
   }
  }
 })

  task.resume()


func dataFromJSON()
    {
     println("Main Dict Values: \(maindict)") //PRINTING ALL VALUES
     let dataArray = maindict["firstName"] as? [String:AnyObject]   
     println("FirstName Values: \(dataArray)") // PRINTING NIL VALUES
    }

Answer 1

这次您的数据结构不是以数组开头，而是使用Dictionary。你的结构就像是：

root Dictionary - ＆gt; ＆＃34;称呼＆＃34; - ＆GT;字典
  根词典 - ＆gt; ＆＃34;台＆＃34; - ＆GT;字典
  根词典 - ＆gt; ＆＃34;的细分＆＃34; - ＆GT;字典

让我们说你想要访问＆＃34; id＆＃34; ＆＃34;称呼＆＃34;，然后：

// Just an exemple of how to download, surely you have your own way
func getJSON(url: NSURL) {
    let session = NSURLSession.sharedSession()
    let request = NSURLRequest(URL: url)
    let task = session.dataTaskWithRequest(request){
        (data, response, downloadError) -> Void in
        if let error = downloadError {
            println(error.localizedDescription)
        } else {
            var jsonError: NSError?

            // cast the result as a Dictionary
            if let dict = NSJSONSerialization.JSONObjectWithData(data, options: nil, error: &jsonError) as? [String: AnyObject] {

                // print the dictionary to check contents
                println(dict)

                if let salutationDictionary = dict["salutation"] as? [String: AnyObject] {

                    if let id = salutationDictionary["id"] as? Int {

                        println(id)

                    }

                }

            }
            if jsonError != nil {
                println(jsonError)
            }
        }
    }
    task.resume()
}

修改

我的朋友，你的代码很乱......我建议你在发生错误时做一些清理，这有助于调试。无论如何，这里是您新代码的更正版本。注意第一行如何声明maindict。此外，您对NSJSONSerialization进行了一次不必要的调用，我对其进行了简化。注意：为了举例说明，我已将dataFromJSON功能代码直接包含在if let parseJSON ...内，但当然并不代表您必须这样做。

var maindict: [String: AnyObject]? var session = NSURLSession.sharedSession() //let parameters = ... let request = NSMutableURLRequest(URL: your_url!) request.HTTPMethod = "POST" var err: NSError? request.HTTPBody = NSJSONSerialization.dataWithJSONObject(parameters, options: nil, error: &err) request.addValue("application/json", forHTTPHeaderField: "Content-Type") request.addValue("application/json", forHTTPHeaderField: "Accept") var task = session.dataTaskWithRequest(request, completionHandler: {data, response, error -> Void in println("Response: \(response)") var err: NSError? maindict = NSJSONSerialization.JSONObjectWithData(data, options: nil, error: &err) as? [String: AnyObject] if err != nil { println(err!.localizedDescription) } else { if let parseJSON = maindict { var success = parseJSON["success"] as? Int println("Succes: \(success)") println("Main Dict Values: \(maindict)") let firstName = maindict!["firstName"] as? String println("FirstName: \(firstName)") } else { let jsonStr = NSString(data: data, encoding: NSUTF8StringEncoding) println("Error could not parse JSON: \(jsonStr)") } } }) task.resume()

请注意细节，并通过与您的尝试进行比较来研究我的修改。我的答案已经在我自己的服务器上测试过了，所以你可以将它用作工作基础。

Answer 2

最简单的方法是使用库。

1）您可以使用swiftyJSON。它使用目标C JSON解析库。 https://github.com/SwiftyJSON/SwiftyJSON

2）如果你想要一个使用纯swift解析器的库，请尝试使用JSONSwift。 github上的自述文件显示了如何从JSON文件中检索嵌套值。将它集成到项目中只需要导入一个文件。 https://github.com/geekskool/JSONSwift

如何使用swift来检索JSON数据

2 个答案: