如何遍历json元素标签

Question

我是 json 新手。我不久前完成了关于 json 的研究，但我对如何控制 json 输出仍然知之甚少。我制作了一个使用 ajax 从控制器获取 json 数据的购物车，并尝试解析输出。最终我没有得到结果。其声明未定义。

这是我的草稿

loop hypermart json element { 

    loop productname element{
        get price based on productname + price
    }
}

所以每个市场都有相同的产品名称和不同的价格。我怎样才能实现这种输出？我被我还没有答案的问题所困。

这是json数据

[{
    "productId":1002,
    "productName":"Moghul Faiza Basmathi",
    "productPic":"",
    "brandName":"Faiza",
    "productVolume":"5kg",
    "barcode":"9555035703811",
    "manufacturer":"Faiza",
    "createdBy":{
        "userId":2,
        "username":"pak.ijan",
        "password":"********",
        "fullName":"Hizan Ahmad",
        "sessionId":"********"},
        "dateCreated":"Jul 9, 2014 3:52:08 AM",
        "modifiedBy":{
            "userId":2,"username":"pak.ijan",
            "password":"********",
            "fullName":"Hizan Ahmad",
            "sessionId":"********"},
            "lastModified":"Jul 9, 2014 3:52:08 AM",
            "status":1,
    "price":[{
        "priceId":0,
        "hypermart":{
            "hypermartId":1,
            "hypermartName":"Tesco",
            "hypermartLogo":"",
            "status":1},
        "priceDate":"Jul 13, 2014 12:17:46 PM",
        "productPrice":0.0,"status":1},
        {"priceId":1,
        "hypermart":{
            "hypermartId":2,
            "hypermartName":"Giant",
            "hypermartLogo":"",
            "status":1},
        "priceDate":"Jul 13, 2014 12:17:46 PM",
        "productPrice":0.0,"status":1},
        {"priceId":2,
        "hypermart":{
            "hypermartId":3,
            "hypermartName":"Jusco",
            "hypermartLogo":"",
            "status":1},
        "priceDate":"Jul 13, 2014 12:17:46 PM",
        "productPrice":0.0,
    "status":1}],
    "tag":"beras faiza basmathi moghul",
    "description":"Moghul Faiza Basmathi",
    "category":{
        "categoryId":7,
        "descEn":"Food",
        "descMy":"Makanan"}
}]

Answer 1

假设你从你的服务器得到一个数据字符串，比如

var myDataJson = [{
  "productId":1002,
  ...
  "price":[{
    "priceId":0,
    "hypermart":{
        "hypermartId":1,
        "hypermartName":
  ...
 }]

现在很简单。你必须解析myDataJson。结果，您立即获得了一个真正的 JavaScript 对象。请记住，JSON 表示 JavaScript 对象表示法。

因此，一种现代的解析方式是：

try {
  var myCartData = JSON.parse(myDataJson);
} catch (ex) {
  ...
}

现在您可以像访问其他所有 Javascript 对象一样访问您的真实 Javascript 对象：

for (key in myCartData) {
   var product = myCartData[key];
   var price = product['price'][0]['productPrice'];
   ...
}

您可能应该寻找其他方法来解析您的 JSON 字符串，因为旧浏览器不支持 JSON.parse()。这里有很多想法：Parse JSON in JavaScript?

Answer 2

很容易循环出一个一个元素的递归。为此，您应该从头开始学习并花一些时间学习。

我正在努力为您解决。

<script src="http://code.jquery.com/jquery-1.9.1.js"></script>
<script>
var data = [
    {
        "productId": 1002,
        "productName": "Moghul Faiza Basmathi",
        "productPic": "",
        "brandName": "Faiza",
        "productVolume": "5kg",
        "barcode": "9555035703811",
        "manufacturer": "Faiza",
        "createdBy": {
            "userId": 2,
            "username": "pak.ijan",
            "password": "********",
            "fullName": "Hizan Ahmad",
            "sessionId": "********"
        },
        "dateCreated": "Jul 9, 2014 3:52:08 AM",
        "modifiedBy": {
            "userId": 2,
            "username": "pak.ijan",
            "password": "********",
            "fullName": "Hizan Ahmad",
            "sessionId": "********"
        },
        "lastModified": "Jul 9, 2014 3:52:08 AM",
        "status": 1,
        "price": [
            {
                "priceId": 0,
                "hypermart": {
                    "hypermartId": 1,
                    "hypermartName": "Tesco",
                    "hypermartLogo": "",
                    "status": 1
                },
                "priceDate": "Jul 13, 2014 12:17:46 PM",
                "productPrice": 100,
                "status": 1
            },
            {
                "priceId": 1,
                "hypermart": {
                    "hypermartId": 2,
                    "hypermartName": "Giant",
                    "hypermartLogo": "",
                    "status": 1
                },
                "priceDate": "Jul 13, 2014 12:17:46 PM",
                "productPrice": 250,
                "status": 1
            },
            {
                "priceId": 2,
                "hypermart": {
                    "hypermartId": 3,
                    "hypermartName": "Jusco",
                    "hypermartLogo": "",
                    "status": 1
                },
                "priceDate": "Jul 13, 2014 12:17:46 PM",
                "productPrice": 370,
                "status": 1
            }
        ],
        "tag": "beras faiza basmathi moghul",
        "description": "Moghul Faiza Basmathi",
        "category": {
            "categoryId": 7,
            "descEn": "Food",
            "descMy": "Makanan"
        }
    }
];

$(document).ready(function(){   

    var martDict = getPriceByName("Moghul Faiza Basmathi")
    console.log(martDict);
    var martDetail = "martDetail";
    var hypermartName = "hypermartName";
    var martPrice = "martPrice";

    for(i in martDict){
        //console.log(martDict[i]);
        //console.log(martDict[i][martDetail]);
        //console.log(martDict[i][martDetail][hypermartName]);
        var martName = martDict[i][martDetail][hypermartName];
        var price = martDict[i][martPrice]
        console.log(martName+" -> "+price);
    }
});

function getPriceByName(name){
    var productName = "productName";
    var price = "price";
    var hypermart = "hypermart";
    var productPrice = "productPrice";
    var martDict = [];
    //console.log(name);
    for(i in data){
        if(data[i][productName] == name){
            //console.log(data[i][productName]);
            var priceList = data[i][price];
            //console.log(priceList);
            for(j in priceList){
                //console.log(priceList[j]);
                //console.log(priceList[j][hypermart])
                var martDetail = priceList[j][hypermart];
                var martPrice = priceList[j][productPrice];
                martDict.push({"martDetail":martDetail,"martPrice":martPrice});
            }
        }
    }

    return martDict;
}
</script>

如果您没有得到答案，请详细说明您的问题。

我已按原样放置所有控制台注释，以便您通过一一打开 cmets 获得更好的主意。