java parse json code example

Example 1: how to parse json in java

import org.json.*;

String jsonString = ... ; //assign your JSON String here
JSONObject obj = new JSONObject(jsonString);
String pageName = obj.getJSONObject("pageInfo").getString("pageName");

JSONArray arr = obj.getJSONArray("posts");
for (int i = 0; i < arr.length(); i++)
{
    String post_id = arr.getJSONObject(i).getString("post_id");
    ......
}

Example 2: java parse json

//from object to JSON 
Gson gson = new Gson();
gson.toJson(yourObject);

// from JSON to object 
yourObject o = gson.fromJson(JSONString,yourObject.class);

Example 3: json parse java

public static void main(String[] args) throws Exception {
    JSONObject jsonObject = (JSONObject) readJsonSimpleDemo("example.json");
    System.out.println(jsonObject);
    System.out.println(jsonObject.get("age"));
}
    
public static Object readJsonSimpleDemo(String filename) throws Exception {
    FileReader reader = new FileReader(filename);
    JSONParser jsonParser = new JSONParser();
    return jsonParser.parse(reader);
}