JSON解析嵌套数组对象

Question

Using Simple-JSON on the following JSON formatted file, I'm having a lot of trouble understanding how to access the objects within the array under "name".

JSON File:

[
    {
        "name":{
            "firstName": "Developer",
            "lastName": "D"
        },
        "id": 00, 
        "permissionLevel": 3, 
        "password": 12345
    },
    {
        "name":{
            "firstName": "Bob",
            "lastName": "Smith"
        }, 
        "id": 01, 
        "permissionLevel": 2, 
        "password": 23456
    }
]

I'm able to obtain the information for all of the other contents because they're not located in a nested array; However, when I attempt to retrieve the objects under "name", all that is output is the String found in the JSON file.

Current code:

String[] searchData = {
                    "name",
                    "firstName",
                    "lastName",
                    "id",
                    "permissionLevel",
                    "password"
                };

jsonArray = (JSONArray)new JSONParser().parse(s);
for(int i = 0; i < jsonArray.size(); i++){
    JSONObject jo = (JSONObject)jsonArray.get(i);
    for(int j = 0; j < searchData.length; j++){
        System.out.println(
                searchData[j] + ": " + jo.get(searchData[j]));
    }
}

Output:

name: [{"firstName":"Developer","lastName":"D"}]
firstName: null
lastName: null
id: 0
permissionLevel: 3
password: 12345
name: [{"firstName":"Bob","lastName":"Smith"}]
firstName: null
lastName: null
id: 1
permissionLevel: 2
password: 23456

As you can see, "name" outputs a String from the JSON file, and not each individual value.

In the end, I need to write a universal code that can accept new "searchData" tags for each file that's input.

1. Might someone be able to direct me how to obtain objects held within nested arrays?
2. Or perhaps I need to use a different Library? If so, which one is the most efficient for Java? I'm not programming for Android, and I continue to find Library suggestions for Android, constantly.

My apologies if this post is a dupe, but no other posts are aiding me.

Answer 1

You should get your firstname and lastname , like:

jo.get("name").get("firstname");
jo.get("name").get("lastname");

Answer 2

To get the objects held within nested arrays/objects, you will have to write a recursive method and flatten the structure into a map. Below example shows the same:

public static void main(String args[]) throws ParseException {
    Object object =  new JSONParser().parse("[    {        \"name\":{            \"firstName\": \"Developer\",            \"lastName\": \"D\"        },        \"id\": 00,         \"permissionLevel\": 3,         \"password\": 12345    },    {        \"name\":{            \"firstName\": \"Bob\",            \"lastName\": \"Smith\"        },         \"id\":01,         \"permissionLevel\": 2,         \"password\": 23456    }]");
    Map<String, Object> pairs = new HashMap<>();
    addValues(object, pairs);
    System.out.println(pairs);
}

public static void addValues(Object object,  Map<String, Object> pairs){
    if(object instanceof JSONObject){
        JSONObject jsonObject = (JSONObject) object;
        for(String key : jsonObject.keySet()){
            if(jsonObject.get(key) instanceof JSONObject || jsonObject.get(key) instanceof JSONArray){
                addValues(jsonObject.get(key), pairs);
            }else{
                pairs.put(key, jsonObject.get(key));
            }
        }
    }else if(object instanceof JSONArray){
        JSONArray jsonArray = (JSONArray)object;
        for(Object element : jsonArray){
            addValues(element, pairs);
        }
    }
}

You can tweak this method to have keys like name.firstname or name.lastname depending on requirements.

Answer 3

I understand that you want the searchData tags to be taken into consideration while parsing the JSON . I would suggest using Google Gson for this case.

You can write a POJO which return the ArrayList<User> for your JSON.

Refer this article on how use Google Gson