Json and Array serialization - Java Spring Boot

Question

Im trying to insert a list of phones with no success.

My Domain Client class

@Entity 
public class Client {
@Id @GeneratedValue(strategy = GenerationType.IDENTITY)
private Integir id;
private String name;
@JsonManagedReference
@ManyToMany(cascade = CascadeType.ALL)
@JoinTable(****)
private List<Phone> phones = new ArrayList<>();
**gets and sets**
 public Client (String name){
 this.name = name;
 }
}

My Domain Phone class

@Entity
public class Phone {
@Id @GeneratedValue(strategy = GenerationType.IDENTITY)
private Integir id;
private String number;
@JsonBackReference
@ManyToMany(mappedBy = "phones")
private List<Client> clients = ArrayList<>();
**gets and sets**
 public Phone(String number) {
 this.number = number;
 } 
}

I have a DTO ClientDTO

public class ClientDTO {
private String name;
private String number;
private List<Phone> numbers = ArryList<>();
**gets and sets** 
}

My service ClientService hava this method:

public Client fromDTO (ClientDTO clientDTO) {
 Client c = new Client(clientDTO.getName());
 for(Phone p: clientDTO.getNumbers()) {
 p.setNumber(x.getNumber);
 p.getClients().addALL(Arrys.asList(c));
 c.getPhones().addAll(Arrys.asList(p));
 }
}

If i try to this in Postman:

{
 "name" : "Teste",
 "numbers": 
 [
 { "number" : "xxxxxx"},
 { "number" : "yyyyyyy"} 
 ]
}

Shows Error 415 : Unsupported Media Type

If i change my ClientDTO to:

public class ClientDTO {
private String name;
private String number;
**gets and sets** 
}

And my method in ClientService to:

public Client fromDTO (ClientDTO clientDTO) {
Client c = new Client(clientDTO.getName());
Phone p = new Phone(clientDTO.getPhone());
p.getClients().addAll(Arrys.asList(c));
c.getPhones().addAll(Arrays.asList(p));
}

And in my postman i send this:

{
 "name" : "Teste",
 "number": "xxxxx" 
}

Works fine.

What Im doing wrong?

Answer 1

Add an empty(no-args) constructor to both Client and Phone entity classes

Client Entity Class

@Entity 
public class Client {
@Id @GeneratedValue(strategy = GenerationType.IDENTITY)
private Integir id;
private String name;
@JsonManagedReference
@ManyToMany(cascade = CascadeType.ALL)
@JoinTable(****)
private List<Phone> phones = new ArrayList<>();
**gets and sets**
 public Client (){}
 public Client (String name){
 this.name = name;
 }
}

Phone Entity Class

@Entity
public class Phone {
@Id @GeneratedValue(strategy = GenerationType.IDENTITY)
private Integir id;
private String number;
@JsonBackReference
@ManyToMany(mappedBy = "phones")
private List<Client> clients = ArrayList<>();
**gets and sets**
 public Phone() {}
 public Phone(String number) {
 this.number = number;
 } 
}

You can't serialize an object if it has no Serializable super-class and has no no-arg constructor. Since You used Phone entity class in ClientDTO and it has no no-arg constructor serialization process fails

• Rodrigo Batista: I included the default constructor but the error persists. So i included the annotation @JsonIgnore on ClientDTO -> List<Phone> and the error ends. But no phone is included. And now? what im doing wrong?