class DJStockPoolDragonHeadItemsModel: Codable {

var isBusiness:Int?
var blockName:String?
//入选价格
var price:Double?

var id: Int?
var blockMarket:Int?
//股票名字
var name:String?

//是否是龙头
var isCock:Int?
//入选时间
var time: String?
var smallMarket:Int?
var stockStatusImg:String?
//股票池名称
var typeName:String?
var market:Int?
var blockCode:String?
//股票代码
var code:String?
var customDate:int?
var blockID:String?
//最高涨幅
var maxRise:Double?
var isBsiness:Int?
}

market 字段后台起先返回的是int,突然有一天返回了string,导致于IOS这边拿不到model数据经过排查查看解析是用swift提供的解析

    if let objArr = obj as? [[String:Any]] {
        let models = objArr.toObjct(type: [DJStockPoolDragonHeadItemsModel].self)
        recvHandler(models)
    } else {
          recvHandler(nil)
    }

  /// 转model
  /// - Parameter type: type
  /// - Returns: model
 func toObjct<T>(type:T.Type)  -> T? where T : Decodable {
      if let obj = try? JSONSerialization.data(withJSONObject: self, options: .prettyPrinted) {
          let decoder =  JSONDecoder()
          if let data = try? decoder.decode(T.self, from: obj) {
              return data
          }
      }
      return nil
  }
为了弄清原因将代码修改如下
/// 转model
  /// - Parameter type: type
  /// - Returns: model
  func toObjct<T>(type:T.Type)  -> T? where T : Decodable {
      if let obj = try? JSONSerialization.data(withJSONObject: self, options: .prettyPrinted) {
          let decoder =  JSONDecoder()
          if let data = try? decoder.decode(T.self, from: obj) {
              return data
          }
          var data:Any?
          do {
              data = try! decoder.decode(T.self, from: obj)
          } catch  {
              print(error)
          }
      }
      return nil
  }
运行后查看
Fatal error: 'try!' expression unexpectedly raised an error: Swift.DecodingError.typeMismatch(Swift.Int, Swift.DecodingError.Context(codingPath: [_JSONKey(stringValue: "Index 0", intValue: 0), CodingKeys(stringValue: "customDate", intValue: nil)], debugDescription: "Expected to decode Int but found a string/data instead.", underlyingError: nil)): file _Test/ArrayExtensions.swift, line 44
2023-10-28 10:12:31.679135+0800 -Test[4259:80177] Fatal error: 'try!' expression unexpectedly raised an error: Swift.DecodingError.typeMismatch(Swift.Int, Swift.DecodingError.Context(codingPath: [_JSONKey(stringValue: "Index 0", intValue: 0), CodingKeys(stringValue: "customDate", intValue: nil)], debugDescription: "Expected to decode Int but found a string/data instead.", underlyingError: nil)): file _Test/ArrayExtensions.swift, line 44
报错信息显示 CodingKeys(stringValue: "customDate", intValue: nil)
查看后台原始数据
![73AD650AE3265779FB0CC0F066EAFA2E.png](https://upload-images.jianshu.io/upload_images/1192250-0d0606e6506d465f.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)

![73ad650ae3265779fb0cc0f066eafa2e.png](https://upload-images.jianshu.io/upload_images/1192250-c297b9b8ce92c769.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)

竟然是string类型，好吧我改。改完string后顺利拿到了数据