Optional fields in Java DTO with validation constraint

Question

I've created a DTO with some properties with validation constraint (like all the properties must be present in JSON Object). Now, I want to make that DTO in a way like if a particular property is missing in JSON Object, it causes no error.

public class UserDTO{
    private String name;
    private String address;
    private String email;
    private String mobileNumber;
}

Now the JSON Object which I want to work could be like this (with missing email).

{
    name:"Hamza",
    address:"ABC",
    mobileNumber:"12345"
}

What should be done? Is there any annotation which makes the field optional?

Answer 1

you can add @JsonIgnoreProperties(ignoreUnknown = true) to ignore all unknow fields (if you don't know which need to ignore). or you can add @JsonIgnore on top of the field (if you know which field need to ignore during deserialization).

@JsonIgnoreProperties(ignoreUnknown = true)
public class UserDTO {
    private String name;
    private String address;
    private String email;
    private String mobileNumber;
}