使用 JSON Java 检索嵌套数组值
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Retrieving nested arrays values with JSON Java
提问by Pablo Fernández
I'm struggling to retrieve some values from a JSON file formatted like this one:
我正在努力从格式如下的 JSON 文件中检索一些值：
{
"search": {
"entry": [
{
"found": "identity=9454532,l=big,ton=grand,k=molvi",
"attribute": [
{
"name": "firstname",
"value": [
"Lucas"
]
},
{
"name": "lastname",
"value": [
"Brandon"
]
}
]
}
],
"return": {
"code": 0,
"message": "Success",
"count": 1
}
}
}
I have tried different approaches (json, gson, jayway-JsonPath) but I don't manage to get the values from the "attribute" array, only those from the first array. I don't know how to specify that "attribute" is an JSONArray and not a JSONObject or how to set the proper path to it. This is the last code I was playing with which stops when it founds an array:
我尝试了不同的方法（json、gson、jayway-JsonPath），但我无法从“属性”数组中获取值，只能从第一个数组中获取值。我不知道如何指定“属性”是 JSONArray 而不是 JSONObject 或如何设置正确的路径。这是我使用的最后一个代码，它在找到数组时停止：
public void String nameObtain (String email) throws IOException{
String link = "http://jsonfile/" + email;
JSONObject json = readJsonFromUrl(link);
JSONObject rootObject = json.getJSONObject("search");
JSONArray firstArray = rootObject.getJSONArray("entry");
for (int i = 0, size = firstArray.length(); i < size; i++) {
JSONObject objectInArray = firstArray.getJSONObject(i);
String[] elementNames = JSONObject.getNames(objectInArray);
System.out.printf("%d ELEMENTS IN CURRENT OBJECT:\n", elementNames.length);
for (String elementName : elementNames) {
String value = objectInArray.getString(elementName);
System.out.printf("name=%s, value=%s\n", elementName, value);
}
}
}
What I would like to do is to get the values Lucas or Brandon. Any help will be much appreciated!
我想做的是获得 Lucas 或 Brandon 的值。任何帮助都感激不尽！
回答by Rishal dev singh
Libraries used:
使用的库：
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
Check the below code and step wise parsing
检查以下代码并逐步解析
JSONObject search = (JSONObject) jsonObject.get("search");//1
JSONArray entry = (JSONArray) search.get("entry");//2
for (int i = 0; i < entry.size(); i++) {
JSONObject jsonObject1 = (JSONObject) entry.get(i);//3
JSONArray jsonarray1 = (JSONArray) jsonObject1.get("attribute");//4
for (int j = 0; j < jsonarray1.size(); j++) {
System.out.println(((JSONObject) jsonarray1.get(j)).get(
"value").toString());//5
}
}
It will give the values mentioned step wise:
它将逐步给出提到的值：
1) {"entry":[{"found":"identity=9454532,l=big,ton=grand,k=molvi","attribute":[{"name":"firstname","value":["Lucas"]},{"name":"lastname","value":["Brandon"]}]}],"return":{"code":0,"count":1,"message":"Success"}}
2) [{"found":"identity=9454532,l=big,ton=grand,k=molvi","attribute":[{"name":"firstname","value":["Lucas"]},{"name":"lastname","value":["Brandon"]}]}]
3) {"found":"identity=9454532,l=big,ton=grand,k=molvi","attribute":[{"name":"firstname","value":["Lucas"]},{"name":"lastname","value":["Brandon"]}]}
4) [{"name":"firstname","value":["Lucas"]},{"name":"lastname","value":["Brandon"]}]
5) ["Lucas"] and ["Brandon"]
1) {"entry":[{"found":"identity=9454532,l=big,ton=grand,k=molvi","attribute":[{"name":"firstname","value":[ "Lucas"]},{"name":"lastname","value":["Brandon"]}]}],"return":{"code":0,"count":1,"message": “成功”}}
2) [{"found":"identity=9454532,l=big,ton=grand,k=molvi","attribute":[{"name":"firstname","value":["Lucas"]} ,{"name":"lastname","value":["Brandon"]}]}]
3) {"found":"identity=9454532,l=big,ton=grand,k=molvi","attribute":[{"name":"firstname","value":["Lucas"]}, {"name":"lastname","value":["Brandon"]}]}
4) [{"name":"firstname","value":["Lucas"]},{"name":"lastname","value":["Brandon"]}]
5) [“卢卡斯”] 和 [“布兰登”]
So basically you have to take care of JSONObject and JSONArray respectively and do the parsing accordingly.
所以基本上你必须分别处理 JSONObject 和 JSONArray 并相应地进行解析。
