将swift对象转换为JSON字符串

2 回答

• 0

  编辑 - 10/31/2017：这个答案主要适用于Swift 3和可能的早期版本 . 截至2017年底，我们现在拥有Swift 4，您应该使用Encodable和Decodable协议在表示之间转换数据，包括JSON和文件编码 . （您可以添加Codable协议以使用编码和解码）

  在Swift中使用JSON的常用解决方案是使用字典 . 所以你可以这样做：

  extension Date {
    var dataDictionary {
      return [
        "year": self.year,
        "month": self.month,
        "day": self.day
      ];
    }
  }
  
  extension Lad {
    var dataDictionary {
      return [
        "firstName": self.firstName,
        "lastName": self.lastName,
        "dateOfBirth": self.dateOfBirth.dataDictionary
      ];  
    } 
  }
  

  然后使用 JSONSerialization 序列化字典格式的数据 .

  //someLad is a Lad object
  
  do {
    // encoding dictionary data to JSON
    let jsonData = try JSONSerialization.data(withJSONObject: someLad.dataDictionary, 
                                                     options: .prettyPrinted)
  
    // decoding JSON to Swift object
    let decoded = try JSONSerialization.jsonObject(with: jsonData, options: [])
    // after decoding, "decoded" is of type `Any?`, so it can't be used
    // we must check for nil and cast it to the right type        
    if let dataFromJSON = decoded as? [String: Any] {
        // use dataFromJSON
    }
  } catch {
      // handle conversion errors
  }
  

  如果你只需要为几个类做这个，提供将它们变成字典的方法是最可读的选项，并不会使你的应用程序显着增大 .

  但是，如果您需要将许多不同的类转换为JSON，那么写出如何将每个类转换为字典将会很繁琐 . 因此，使用某种反射API以便能够列出对象的属性会很有用 . 最稳定的选择似乎是EVReflection . 使用EVReflection，对于我们想要变成json的每个类，我们可以这样做：

  extension SomeClass: EVReflectable { }
  
  let someObject: SomeClass = SomeClass();
  let someObjectDictionary = someObject.toDictionary();
  

  然后，就像之前一样，我们可以使用 JSONSerialization 将我们刚刚获得的字典序列化为JSON . 我们只需要使用 object.toDictionary() 而不是 object.dataDictionary .

  如果您不想使用 EVReflection ，则可以使用Mirror类自己实现反射（能够查看对象具有哪些字段并迭代它们） . 有一个解释如何为此目的使用镜像here .

  因此，定义了 .dataDictionary 计算变量或使用 EVReflection 的 .toDictionary() 方法，我们可以做

  class ApiService {
  
    func postDataToTheServer(lad: Lad)  {
      //if using a custom method
      let dict = lad.dataDictionary
  
      //if using EVReflection
      let dict = lad.toDictionary()
  
      //now, we turn it into JSON
      do {
        let jsonData = try JSONSerialization.data(withJSONObject: dict, 
                                                         options: .prettyPrinted)
        // send jsonData to server
      } catch {
        // handle errors
      }
    }
  }
  

  回复于 2024-04-20T11:16:35+08:00
• 4

  愿这个GitHub代码能为您提供帮助 .

  protocol SwiftJsonMappable {
     func getDictionary() -> [String: Any]
     func JSONString() -> String
  }
  
  
  
  extension SwiftJsonMappable {
  
  //Convert the Swift dictionary to JSON String
  func JSONString()  -> String {
      do {
          let jsonData = try JSONSerialization.data(withJSONObject: self.getDictionary(), options: .prettyPrinted)
          // here "jsonData" is the dictionary encoded in JSON data
  
          let jsonString = String(data: jsonData, encoding: .utf8) ?? ""
          // here "decoded" is of type `Any`, decoded from JSON data
          return jsonString
          // you can now cast it with the right type
  
      } catch {
          print(error.localizedDescription)
      }
      return ""
  
  }
  
  //Convert Swift object to Swift Dictionary
  func getDictionary() -> [String: Any] {
      var request : [String : Any] = [:]
      let mirror = Mirror(reflecting: self)
      for child in mirror.children {
          if let lable = child.label {
              //For Nil value found for any swift propery, that property should be skipped. if you wanna print nil on json, disable the below condition
              if !checkAnyContainsNil(object: child.value) {
  
                  //Check whether is custom swift class
                  if isCustomType(object: child.value) {
                      //Checking whether its an array of custom objects
                      if isArrayType(object: child.value) {
                          if let objects = child.value as? [AMSwiftBase] {
                              var decodeObjects : [[String:Any]] = []
                              for object in objects {
                                  //If its a custom object, nested conversion of swift object to Swift Dictionary
                                  decodeObjects.append(object.getDictionary())
                              }
                              request[lable] = decodeObjects
  
                          }
                      }else {
  
                          //Not an arry, and custom swift object, convert it to swift Dictionary
                          request[lable] = (child.value as! AMSwiftBase).getDictionary()
                      }
                  }else {
                      request[lable] = child.value
                  }
              }
          }
      }
      return request
  }
  
  //Checking the swift object is swift base type or custom Swift object
  private func isCustomType(object : Any) -> Bool {
  
      let typeString = String(describing: type(of: object))
      if typeString.contains("String") || typeString.contains("Double") || typeString.contains("Bool") {
          return false
      }
      return true
  }
  
  //checking array
  private func isArrayType(object : Any) -> Bool {
  
      let typeString = String(describing: type(of: object))
      if typeString.contains("Array"){
          return true
      }
      return false
  }
  
  //Checking nil object
  private func checkAnyContainsNil(object : Any) -> Bool {
      let value = "\(object)"
      if value == "nil" {
          return true
      }
      return false
  }
  
  }
  

  https://github.com/anumothuR/SwifttoJson

  回复于 2024-04-20T11:16:35+08:00