Store response in a variable-CodePudding

I'm trying to store every response to a Arrays.asList in Builder but it won't work. I been trying a lot but no luck. How to do it? It's my first time to store a response in a single variable.

Storing response in Arrays.asList in Builder is just a test. Kindly suggest the best way to do it.

//model entity

@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
@Entity
public class Student{
   private String firstname;
   private String lastname;
   private String age;
}

//model entity

@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
public class StudentResponse{
   private List<String> responsefirstname;
   private List<String> responselastname;
   private List<String> responseage;

   public static StudentResponse convertToResponse(List<Student> student){
       return StudentResponse.builder()
   .responsefirstname(Arrays.asList(student.get(0).getFirstname))
   .responselastname(Arrays.asList(student.get(0).getLastname))
   .responseage(Arrays.asList(student.get(0).getAge))
   .build();
}
}

//Service

public class StudentService{

   @Autowired
    private StudentRepo repo;

    public StudentResponse findStudent(String sfirstname){
        List<Student> students =  repo.findByFirstname(sfirstname);
        List<StudentResponse> studentResponse = students.stream
        //   .map(StudentResponse::convertToResponse) //dont work
           .collect(Collectors.toList());
        return studentResponse
    }
}

Expected response must be like this

{
 "firstname":["justin","ana","marie"],
 "lastname": ["last1","last2","las3"],
 "age": [45,55,28]
}

not multiple like this

{
 "firstname":"justin",
 "lastname": "last2",
 "age": 55
},
{
 "firstname":"justin",
 "lastname": "last1",
 "age": 45
}

CodePudding user response：

Just loop over the student list:

public static StudentResponse convertToResponse(List<Student> students) {
    List<String> firstNames = new ArrayList<>(students.size());
    List<String> lastNames = new ArrayList<>(students.size());
    List<Integer> ages = new ArrayList<>(students.size());

    for (Student student : students) {
        firstNames.add(student.getFirstName());
        lastNames.add(student.getLastNames());
        ages.add(student.getAge());
    }

    return StudentResponse.builder()
            .responsefirstname(firstNames)
            .responselastname(lastNames)
            .responseage(ages)
            .build();
}