What is the best way to create complex json in java?

Question

I want to create a request body to test an API. The request body is a complex JSON as below:

{
  "certificate_registry": {
    "images": [
      {
        "url": "https://path.jpg"
      }
    ],
    "truck": {
      "plate": "aaaa-1111",
      "truck_model_id": 1,
      "truck_type_id": 1
    }
  }
}

Please suggest me what is the best way to create new complex JSON in java?

I used the tool online but it creates many classes for only 1 request body. It's not easy to understand, maintain.

Answer 1

This is something you can do by marshalling POJO's to JSON. For example with a framework such as Jackson.

As described in this tutorial you can use a Jackson ObjectMapper:

import com.brunozambiazi.model.User;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.util.Calendar;
import java.util.HashSet;

public class SerializationTest {

    public static void main(String[] args) throws Exception {
        User user = new User();
        user.setId(1L);
        user.setName("User");
        user.setBirthDate(Calendar.getInstance());
        user.setEmails(new HashSet<String>());
        user.getEmails().add("[email protected]");
        user.getEmails().add("[email protected]");

        ObjectMapper mapper = new ObjectMapper();

        String json = mapper.writeValueAsString(user);
        System.out.println(json);
    }

}

That will result in:

{"id":1,"name":"User","birthDate":1439662844272,"emails":["[email protected]","[email protected]"]}