Error Domain=NSCocoaErrorDomain Code=3840 "JSON text did not start with array or object and option to allow fragments not set." UserInfo={NSDebugDescription=JSON text did not start with array or object and option to allow fragments not set.}

let path = Bundle.main.path(forResource: "countryData", ofType: "json")
let url = URL(fileURLWithPath: path!)
// 带throws的方法需要抛异常
 do {
    /*
     * try 和 try! 的区别
     * try 发生异常会跳到catch代码中
     * try! 发生异常程序会直接crash
     */
   let data = try Data(contentsOf: url)
   let jsonData:Any = try JSONSerialization.jsonObject(with: data, options: JSONSerialization.ReadingOptions.mutableContainers)
   let jsonArr = jsonData as! NSArray
   
   for dict in jsonArr {
    print(dict)
   }
  } catch let error as Error! {
   print("读取本地数据出现错误!",error)
  }