Jackson and json array

All good people? I'm killing my head for a few days but without success.

I need to insert information into the DB that comes through JSON. It turns out that when an array comes, it does not want to insert.

Explain better:

In the domain, I have the client class:

@Entity
public class Cliente
private String nome;
@ManytoMany
private List<Telefone> telefones = new ArrayList<>();

public Cliente() {}

getters e setters 

And I have the telephone class:

@Entity
public class Telefone
private String numero;
@JsonIgnore
@ManytoMany
private List<Cliente> clientes = new ArrayList<>();

public Telefone () {}

getters e setters

I created a DTO Client class:

public class ClienteDTO
private String nome;
private String numero;

public ClienteDTO () {}

getters e setters

In the service I created the ClientService class which, in addition to some methods, has the following method:

public Cliente converteDoDTO(ClienteDTO clienteDTO) {

Cliente c = new Cliente(clienteDTO.getNome());
Telefone t = new Telefone(clienteDTO.getNumero());

c.getTelefones().addALL(Arrays.asList(t));
t.getClientes().addALL(Arrays.asList(c));

}

This way if I pass JSON this way:

{
  "nome" : "Teste",
  "telefone" : "123"
}

It will be included in the DB.

But I would like it to be as follows:

{
  "nome" : "Teste",
  "telefones" : 
 [
   {"telefone" : "123"},
   {"telefone" : "456"},
   {"telefone" : "789"}
 ]
}

Only your doing this, the "phones" comes empty. And the bank only enters the name. I searched and saw that I have to use ObjectMapper, something like this:

ObjectMapper mapper = new ObjectMapper();
List<Telefone> telefones = mapper.readValue(jsonInput, new TypeReference<List<telefone>>(){});

I happen to not know where to create this. If it is in the serivce, in the DTO, in the Domain. I'm very lost. Could anyone help? Thank you in advance.