How to convert jsonString to JSONObject in Java

To convert a JSON string to a JSONObject in Java, you can use the JSONObject constructor that takes a String as an argument. First, ensure you have the org.json library in your project:

Maven:

<dependency>
    <groupId>org.json</groupId>
    <artifactId>json</artifactId>
    <version>20231013</version>
</dependency>

Gradle:

implementation 'org.json:json:20231013'

Include the necessary imports and handle JSONException as shown below:

import org.json.JSONObject;
import org.json.JSONException;

public class Main {
    public static void main(String[] args) {
        String jsonString = "{\"name\":\"John\", \"age\":30, \"city\":\"New York\"}";
        try {
            JSONObject jsonObject = new JSONObject(jsonString);
            String name = jsonObject.getString("name");
            int age = jsonObject.getInt("age");
            String city = jsonObject.getString("city");
            System.out.println(name + ", " + age + ", " + city);
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }
}

Alternatively, you can use the Jackson library to parse JSON strings. Here's an example using ObjectMapper and JsonNode:

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

public class Main {
    public static void main(String[] args) throws Exception {
        String jsonString = "{\"name\":\"John\", \"age\":30, \"city\":\"New York\"}";
        ObjectMapper mapper = new ObjectMapper();
        JsonNode jsonNode = mapper.readTree(jsonString);
        String name = jsonNode.get("name").asText();
        int age = jsonNode.get("age").asInt();
        String city = jsonNode.get("city").asText();
        System.out.println(name + ", " + age + ", " + city);
    }
}