如何在不遍历整个json的情况下检索和更新json数组元素 [英] How to retrieve and update json array element without traversing entire json
问题描述
我有一个非常复杂的json结构.它包含许多array elements，并且那些数组元素包含其他数组元素，依此类推.
请参见下面的json树结构.
I have a very complex json structure. It contains many array elements and those array elements contains other array elements and so on..
Please see below json tree structure.
Json树结构1:
Json树结构2:
正如上面以黄色突出显示的那样，我想更新"rdKey"字段的值.
我写了下面的代码，它工作正常:
As highlighted above in yellow, I want to update the value of "rdKey" field.
I wrote below code and it is perfectly working fine :
String json = "escaped string (as it's a big string, I can't put it here)";
JSONObject jsonObj = new JSONObject(json);
if (jsonObj.has("responseMap")) {
JSONObject responseMap = jsonObj.getJSONObject("responseMap");
if (responseMap.has("ValueJson")) {
JSONObject valueJson = responseMap.getJSONObject("ValueJson");
if (valueJson.has("ticketBean_CM")) {
JSONObject ticketBean_CM = valueJson.getJSONObject("ticketBean_CM");
if (ticketBean_CM.has("addByGamma")) {
String addByGamma = ticketBean_CM.getString("addByGamma");
System.out.println(addByGamma);
if (addByGamma.equals("VCE")) {
if (responseMap.has("ScreenJson")) {
JSONObject screenJson = responseMap.getJSONObject("ScreenJson");
if (screenJson.has("sections")) {
JSONArray sectionArray1 = screenJson.getJSONArray("sections");
if (sectionArray1.length() > 0) {
JSONObject section0 = sectionArray1.getJSONObject(0);
if (section0.has("sections")) {
JSONArray sectionArray2 = section0.getJSONArray("sections");
if (sectionArray2.length() > 3) {
JSONObject section6 = sectionArray2.getJSONObject(3);
if (section6.has("sections")) {
JSONArray sectionArray3 = section6.getJSONArray("sections");
if (sectionArray3.length() > 1) {
JSONObject section8 = sectionArray3.getJSONObject(1);
if (section8.has("elements")) {
JSONArray elementsArray1 = section8
.getJSONArray("elements");
if (elementsArray1.length() > 0) {
JSONObject elements1 = elementsArray1.getJSONObject(0);
if (elements1.has("elements")) {
JSONArray elementsArray2 = elements1
.getJSONArray("elements");
if (elementsArray2.length() > 4) {
JSONObject elements2 = elementsArray2
.getJSONObject(4);
if (elements2.has("rdKey")) {
System.out.println(
elements2.getString("rdKey"));
elements2.put("rdKey",
"CircuitID(FullPartial)");
System.out.println(
elements2.getString("rdKey"));
System.out.println(jsonObj.toString());
}
}
}
}
}
}
}
}
}
}
}
}
}
}
}
}
}
如果有更好的解决方案，我希望你们能帮助我.我可以在不遍历整个json对象的情况下做到这一点(直到找到相关字段)吗?如果json树结构发生更改，则此解决方案将不起作用，作为此代码的成功方案，它必须是静态的.
I want you guys to help me if there is any better solution for this. Can I do it without traversing the entire json object (till I find the concerned field) ? This solution will not work if json tree structure gets changes, it needs to be static as a success scenario of this code.
请提出更好的解决方案.
Please suggest better solution.
推荐答案
如果要转义JSON遍历，则可以使用JSONPointer，该库在同一org.json库中可用.
例如:
If you want to escape traversing of JSON then you can use JSONPointer, available in same org.json library.
E.g.:
String query = <json_pointer_query to element array>
JSONPointer pointer = new JSONPointer(query);
JSONObject elementsArrayJSON = (JSONObject) pointer.queryFrom(jsonObj);
elementsArrayJSON.put("rdKey","CircuitID(FullPartial)");
JSON指针查询语言可以通过以下方式引用:
JSON Pointer query language can be referred in:
https://tools.ietf.org/html/rfc6901
注意: JSON指针非常基础，它不支持通配符.因此，您需要确定元素名称，否则会引发异常.
Note: JSON Pointer is pretty basic, it doesn't support wild card. So you need to be sure about element names, otherwise it would throw exception.
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