如何快速为POST请求创建参数

Question

我正在尝试为JSON POST请求生成参数， 这是我要实现的目标：

{
      "Associate_Name": "SAURABH K WATT",
      "Associate_Code": "DT1006",
      "Transaction_No": "6",
      "TRANSACTION_MODE": "2",
      "COMPANY_NO": "cogni",
      "LOCATION_NO": "NOIDA",
      "REPORTING_DATE": "2019-07-09",
      "SERVER_DATE": "2019-07-11",
      "ItemDtail": [
        {
          "LI_NO": "1",
          "CUSTOMER_ID": "C103",
          "PROJECT_ID": "IMSGTPL0052",
          "Activity_Id": "DEVELOPMEN",
          "ACTIVITY": "DEVELOPMEN",
          "ACTIVITY_DETAILS": "test",
          "TOTAL_HOURS": "1.30",
          "PERCENTAGE": "16.25",
          "STATUS": "2",
          "REMARKS1": "",
          "REMARKS2": "",
          "REMARKS3": "",
          "user_id": "62",
          "Doc_Status": "F",
          "ConvertedTime": "1.30",
          "CaseId": "0"
        },
        {
          "LI_NO": "2",
          "CUSTOMER_ID": "C103",
          "PROJECT_ID": "PROJ1029",
          "Activity_Id": "DEV2",
          "ACTIVITY": "DEV2",
          "ACTIVITY_DETAILS": "sat",
          "TOTAL_HOURS": "6.30",
          "PERCENTAGE": "78.75",
          "STATUS": "1",
          "REMARKS1": "",
          "REMARKS2": "",
          "REMARKS3": "",
          "user_id": "62",
          "Doc_Status": "F",
          "ConvertedTime": "6.30",
          "CaseId": "0"
        }
      ]
    }

到目前为止，我已经这样尝试过：

let param : [String:Any] = [
                "Associate_Name": "SAURABH K WATT",
                "Associate_Code": "DT1006",
                "Transaction_No": "13",
                "TRANSACTION_MODE": "1",
                "COMPANY_NO": "cogni",
                "LOCATION_NO": "NOIDA",
                "REPORTING_DATE": "2019-07-05",
                "SERVER_DATE": "2019-07-11",
                "ItemDtail": [
                    [
                        "LI_NO": "1",
                        "CUSTOMER_ID": "C103",
                        "PROJECT_ID": "IMSGTPL0052",
                        "Activity_Id": "DEVELOPMEN",
                        "ACTIVITY": "DEVELOPMEN",
                        "ACTIVITY_DETAILS": "test",
                        "TOTAL_HOURS": "1.30",
                        "PERCENTAGE": "16.25",
                        "STATUS": "2",
                        "REMARKS1": "",
                        "REMARKS2": "",
                        "REMARKS3": "",
                        "user_id": "62",
                        "Doc_Status": "F",
                        "ConvertedTime": "1.30",
                        "CaseId": "0"
                    ]
                ]
            ]

但是从这种存储方式来看，我得到了错误的JSON序列，最终的JSON打印如下：

JSON string = 
{
  "Transaction_No" : "13",
  "TRANSACTION_MODE" : "1",
  "COMPANY_NO" : "cogni",
  "SERVER_DATE" : "2019-07-11",
  "Associate_Code" : "DT1006",
  "ItemDtail" : [
    {
      "TOTAL_HOURS" : "1.30",
      "ACTIVITY" : "DEVELOPMEN",
      "ConvertedTime" : "1.30",
      "CUSTOMER_ID" : "C103",
      "Activity_Id" : "DEVELOPMEN",
      "PERCENTAGE" : "16.25",
      "REMARKS1" : "",
      "REMARKS3" : "",
      "ACTIVITY_DETAILS" : "test",
      "user_id" : "62",
      "CaseId" : "0",
      "STATUS" : "2",
      "LI_NO" : "1",
      "PROJECT_ID" : "IMSGTPL0052",
      "Doc_Status" : "F",
      "REMARKS2" : ""
    }
  ],
  "REPORTING_DATE" : "2019-07-05",
  "LOCATION_NO" : "NOIDA",
  "Associate_Name" : "SAURABH K WATT"
}

这是错误的。请帮忙，我到处搜索过但没有找到任何解决方案，我在过去三天中一直陷入困境。