Insert Json within Json

Question

In a client-server structure (in JAVA), I have the following Json structures separately (example): Structure of Students:

{"idAluno":1,"nomeAluno":"Teste da Silva","listaDeTurmas":[1,2]}

Structure of Classes:

{"idTurma":1,"nomeTurma":"Redes"}
{"idTurma":2,"nomeTurma":"Compiladores"}

Each structure is managed by a different Java application. Another application requests each of them. After a request to the Students, I receive as a response the structure I referenced above. In the case of a search request, I need to display the data of the class in question in the Class Array. Example:

{ 
    "idAluno": 1,
    "nomeAluno": "Teste da Silva",
    "listaDeTurmas": [
        {
            "idTurma": 1,
            "nomeTurma": "Redes"
        },
        {
            "idTurma": 2,
            "nomeTurma": "Compiladores"
        }
    ]
}

For each class id, I make a request in the Classes application and receive the corresponding structure of the searched class. But what is the correct way to modify the Array in the student’s Json and have the class data displayed instead of simply its code (as the example above)? I need to dismember the two structures and create a new Json from there or there’s a simpler way to do this?

Answer 1

An idea for the solution:

1. Make the Student JSON request and mount it inside a Student object
2. Make the requisition of Classes, according to the ids you already have.
3. Assemble a Class object according to what you receive in the class JSON request.
4. Creates a new field in the Student object of type ArrayList<Turma> and passes all the objects you search from Class to that array.
5. Generates the new JSON from Student, with the list of Classes already added to the object.

Classes

Attention here: Create only the set method of the variable int[] listaDeTurmas in the Student class so that it does not reproduce its array of int[] when you do the export of class with the later classes

public class Aluno {

  private int idAluno;
  private String nomeAluno;
  private int[] listaDeTurmas;

  private List<Turma> listaTurma = new ArrayList<>();

  public void setListaDeTurmas(int[] listaDeTurmas) {
      this.listaDeTurmas = listaDeTurmas;
  }
  //metodo para adicionar elemento a sua List
  public void addTurma(Turma t) {
      listaTurma.add(t);
  }
  //gets e sets das outras três variáveis...
} 

---

public class Turma {

  private int idTurma;
  private String nomeTurma;

  //gets e sets...
}

---

To play and facilitate the process I used the library Jackson to break the JSON

 import com.fasterxml.jackson.databind.ObjectMapper;
 import java.io.IOException;

 public static void main(String[] args)  {
    ObjectMapper mapper = new ObjectMapper();
    try {
        String alunoString = "{\"idAluno\":1,\"nomeAluno\":\"Teste da Silva\",\"listaDeTurmas\":[1,2]}";
        Aluno aluno = mapper.readValue(alunoString, Aluno.class);

        String turma1String = "{\"idTurma\":1,\"nomeTurma\":\"Redes\"}";
        Turma turma1 = mapper.readValue(turma1String, Turma.class);

        String turma2String = "{\"idTurma\":2,\"nomeTurma\":\"Compiladores\"}";
        Turma turma2 = mapper.readValue(turma2String, Turma.class);

        aluno.addTurma(turma1);
        aluno.addTurma(turma2);

        String jsonAlunoCompleto = mapper.writeValueAsString(aluno);
        System.out.println(jsonAlunoCompleto);
        //{"idAluno":1,"nomeAluno":"Teste da Silva","listaTurma":[{"idTurma":1,"nomeTurma":"Redes"},{"idTurma":2,"nomeTurma":"Compiladores"}]}
    } catch (IOException e) {
        System.out.println(e.getCause());
    }

}