Reading JSON file using json-smart

Question

I am trying to read the values from a JSON file to array for further processing. I am using JSON-Smart 1.2.0 library for the same. Due to some restrictions, I can not use the 2.0 version.

I am getting the following exception.

java.lang.ClassCastException: net.minidev.json.JSONArray cannot be cast to net.minidev.json.JSONObject

I am even tried using JSONArray instead of JSONObject. What I am doing wrong over here? Is this correct way to read json content?

Below is the java code.

JSONObject json = (JSONObject) JSONValue.parseWithException(browsers);
JSONArray array = (JSONArray) json.get("friends");

for (int i = 0; i < array.size(); i++) {
    JSONObject cap = (JSONObject) array.get(i);
    String first = (String) cap.get("name");
    System.out.println(first);
}

Below is the json file content.

[
  {
    "friends": [
      {
        "id": 0,
        "name": "test1"
      },
      {
        "id": 1,
        "name": "test2"
      }
    ]
  }
]

score 3 · Accepted Answer · answered Jun 12 '14 at 13:18

3

Your JSON contains an array which has one single object element so you should parse it like that:

JSONArray root = (JSONArray) JSONValue.parseWithException(json);
JSONObject rootObj = (JSONObject) root.get(0);
JSONArray array = (JSONArray) rootObj.get("friends");

for (int i = 0; i < array.size(); i++) {
    JSONObject cap = (JSONObject) array.get(i);
    String first = (String) cap.get("name");
    System.out.println(first);
}

If it can have more elements add a for loop instead of root.get(0).

answered Jun 12 '14 at 13:18

cy3er

1,699
11
14

Is it possible to have the json file without the root named "friends"? – Purus Jun 12 '14 at 13:37
Yes, you could have a JSON like this: `[{"id":0,"name":"test1"},{"id":1,"name":"test2"}]` – cy3er Jun 12 '14 at 13:43
In that case you could leave the 2nd and 3rd lines and iterate through the root. – cy3er Jun 12 '14 at 13:54

Reading JSON file using json-smart

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