在JSON中查找深层嵌套的键/值 [英] Finding deeply nested key/value in JSON

问题描述

假设我有一个这样的JSON数组：

Suppose I have a JSON array like this:

[
    {
        "id": "429d30a1-9364-4d9a-92e0-a17e00b3afba",
        "children": [],
        "parentid": "",
        "name": "Expo Demo"
    }, 
    {
        "id": "f80f1034-9110-4349-93d8-a17e00c9c317",
        "children": 
            [
                {
                    "id":"b60f2c1d-368b-42c4-b0b2-a1850073e1fe", 
                    "children":[], 
                    "parentid":"f80f1034-9110-4349-93d8-a17e00c9c317", 
                    "name":"Tank"
                }
            ],
        "parentid": "",
        "name": "Fishtank"
    }, 
    {
        "id": "fc8b0697-9406-4bf0-b79c-a185007380b8",
        "children": [
            {
                "id":"5ac52894-4cb6-46c2-a05a-a18500739193", 
                "children":[
                    {
                        "id": "facb264c-0577-4627-94a1-a1850073c270",
                        "children":[
                            {
                                "id":"720472b5-189e-47f1-97a5-a18500a1b7e9", 
                                "children":[], 
                                "parentid":"facb264c-0577-4627-94a1-a1850073c270", 
                                "name":"ubSubSub"
                            }],
                        "parentid": "5ac52894-4cb6-46c2-a05a-a18500739193",
                        "name": "Sub-Sub1"
                    }], 
                "parentid":"fc8b0697-9406-4bf0-b79c-a185007380b8", "name":"Sub"
            },
            {
                "id":"4d024610-a39b-49ce-8581-a18500739a75", 
                "children":[], 
                "parentid":"fc8b0697-9406-4bf0-b79c-a185007380b8", 
                "name":"Sub2"
            }
        ],
        "parentid": "",
        "name": "Herman"
    }, 
    {
        "id": "a5b140c9-9987-4e6d-a883-a18c00726883",
        "children": [
            {
                "id":"fe103303-fd5e-4cd6-81a0-a18c00733737", 
                "children":[], 
                "parentid":"a5b140c9-9987-4e6d-a883-a18c00726883", 
                "name":"Contains Spaces"
            }],
        "parentid": "",
        "name": "Kiosk"
    }
]

不，我想找到一个基于id的特定对象一旦我拥有它，我需要它的孩子及其所有孩子的孩子

No I want to find a certain object based on a id and once I have that, I need its children and all its childrends children

所以，如果 4d024610-a39b-49ce，我想要找到带有id的元素-8581-a18500739a75

应该找到元素 Sub2

现在它应该生成所有的子元素ids巫婆：

And now it should produce all the child elements ids witch will be:

facb264c-0577-4627-94a1-a1850073c270
720472b5-189e-47f1-97a5-a18500a1b7e9

让我说我会做

findElementsChildren("4d024610-a39b-49ce-8581-a18500739a75")

所以我想它的两个部分，首先找到父元素。然后找到它的孩子儿童孩子等等。

So i guess its two parts, first find the "parent" element. Then find its childrends childrends children etc..

任何帮助都将不胜感激！

Any help would be much appreciated!

推荐答案

您可以使用递归来解决无限嵌套的问题。使用Gson，它将类​​似于以下代码片段（未经过测试）。其他库也将提供结构作为JsonElement。

You can use recursion to solve the problem of unlimited nesting. With Gson, it would be something like the following code snippet (not tested). Other libraries will provide structures as JsonElement as well.

private JsonElement findElementsChildren(JsonElement element, String id) {
    if(element.isJsonObject()) {
        JsonObject jsonObject = element.getAsJsonObject();
        if(id.equals(jsonObject.get("id").getAsString())) {
            return jsonObject.get("children");
        } else {
            return findElementsChildren(element.get("children").getAsJsonArray(), id);
        }
    } else if(element.isJsonArray()) {
        JsonArray jsonArray = element.getAsJsonArray();
        for (JsonElement childElement : jsonArray) {
            JsonElement result = findElementsChildren(childElement, id);
            if(result != null) {
                return result;
            }
        }
    }

    return null;
}

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