JSON Processing in Java

ObjectMapper mapper = new ObjectMapper();
String json = mapper.writeValueAsString(object);
MyClass obj = mapper.readValue(json, MyClass.class);

import com.fasterxml.jackson.databind.ObjectMapper;

class User {
  public int id;
  public String name;
}

public class Main {

  public static void main(String[] args) throws Exception {

    ObjectMapper mapper = new ObjectMapper();

    // Java object to JSON
    User user = new User();
    user.id = 1;
    user.name = "John";

    String jsonString = mapper.writeValueAsString(user);
    System.out.println("JSON: " + jsonString);

    // JSON to Java object
    String jsonInput = "{\"id\":2,\"name\":\"Alex\"}";
    User userObj = mapper.readValue(jsonInput, User.class);

    System.out.println(userObj.id + " " + userObj.name);

  }
}

// Output:
// JSON: {"id":1,"name":"John"}
// 2 Alex

• 1 JavaScript Object Notation.
• 2 Lightweight data format.
• 3 Used for data exchange.
• 4 Human-readable format.

• 1 Jackson – most popular library.
• 2 Gson – Google library.
• 3 JSON.simple – lightweight library.
• 4 org.json – basic JSON handling.

• 1 Serialization – Java to JSON.
• 2 Deserialization – JSON to Java.
• 3 Parsing JSON strings.
• 4 Mapping to Java objects.

• 1 Easy data exchange.
• 2 Lightweight format.
• 3 Widely supported.
• 4 Used in REST APIs.