获取 JSON 字符串的列名

Question

I got this problem when i was trying to get Column list from a JSON String . Im getting JSON String with ajax :

 var jsonData = $.ajax({ method: "GET", url: "read.jsp", data: {title: option}, dataType: "json", async: false }).responseText;

I choose a JSON file from a list and i get it

and I tried to Get column names with this :

 var newData= JSON.parse(jsonData).["0"]; for(var i = 0; i < newData.length; i++) { var columnsIn = newData[i]; for(var key in columnsIn){ alert(key); } }

The problem is with : ["0"] , when i replace it with the name of the first attribut , it works.

PS: Json file is not the same.

And this is an exemple of A json file :

    {
    "ASSETMboSet": {
        "rsStart": 0,
        "rsCount": 10,
        "rsTotal": 1262,
        "ASSET": [
            {
                "rowstamp": "[0 0 0 0 2 -100 91 -13]",
                "Attributes": {
                    "ASSETNUM": {
                        "content": "1000"
                    },
                    "SERIALNUM": {
                        "content": "12346"
                    },
                    "VENDOR": {
                        "content": "1001"
                    },
                    "MANUFACTURER": {
                        "content": "1001"
                    },
                    "PURCHASEPRICE": {
                        "content": 0
                    },
                    "REPLACECOST": {
                        "content": 0
                    }, .....

And this is an other exemple because its not the same json file i want to get column names from it :

{
    "executionTime": "2018-02-16 05:49:04 AM",
    "stationBeanList": [
        {
            "id": 72,
            "stationName": "W 52 St & 11 Ave",
            "availableDocks": 31,
            "totalDocks": 39,
            "latitude": 40.76727216,
            "longitude": -73.99392888
 },
        {
            "id": 79,
            "stationName": "Franklin St & W Broadway",
            "availableDocks": 19,
            "totalDocks": 33,
            "latitude": 40.71911552,
            "longitude": -74.00666661}`

Answer 1

1. Do not use async: false . Ever .

2. You have to reach "Attributes" and get the Object.keys of that :

 let data = { "ASSETMboSet": { "rsStart": 0, "rsCount": 10, "rsTotal": 1262, "ASSET": [{ "rowstamp": "[0 0 0 0 2 -100 91 -13]", "Attributes": { "ASSETNUM": { "content": "1000" }, "SERIALNUM": { "content": "12346" }, "VENDOR": { "content": "1001" }, "MANUFACTURER": { "content": "1001" }, "PURCHASEPRICE": { "content": 0 }, "REPLACECOST": { "content": 0 } } }] } // end ASSETMboSet } // end data let keys = Object.keys(data.ASSETMboSet.ASSET[0].Attributes) console.log("keys = ", keys)

Answer 2

The two JSON respones:

{
"ASSETMboSet": {
    "rsStart": 0,
    "rsCount": 10,
    "rsTotal": 1262,
    "ASSET": [
        {
            "rowstamp": "[0 0 0 0 2 -100 91 -13]",
            "Attributes": {
                "ASSETNUM": {
                    "content": "1000"
                },
                "SERIALNUM": {
                    "content": "12346"
                },
                "VENDOR": {
                    "content": "1001"
                },
                "MANUFACTURER": {
                    "content": "1001"
                },
                "PURCHASEPRICE": {
                    "content": 0
                },
                "REPLACECOST": {
                    "content": 0
                }, .....

And

{ "executionTime": "2018-02-16 05:49:04 AM", 
  "stationBeanList": [ 
    { "id": 72, "stationName": "W 52 St & 11 Ave", "availableDocks": 31, "totalDocks": 39, "latitude": 40.76727216, "longitude": -73.99392888, "statusValue": "In Service", "statusKey": 1, "cationTime": "2018-02-16 05:47:06 AM" }, 
    { "id": 79, "stationName": "W 52 St & 11 Ave", "availableDocks": 31, "totalDocks": 39,

are completely different in their structure.

So there is no way to automatically detect the column names. You need to know the structure of the JSON you request, and based on that information create a function for each of them that looks for the column names.

But you can't create a magic function that can extract the column names of any JSON response without knowing how the response looks like.