java.lang.ClassCastException using restTemplate

Question

This is my service code where I am calling "http://localhost:3232/survey" and it will return List of Employees. Method getListEmployee is working fine but when I call method findEmpById it shows me the error

Service class

@Service
public class EmployeeService {

    public List<Employee> getListEmployee() {
        RestTemplate restTemplate = new RestTemplate();
        List<Employee> data = restTemplate.getForObject("http://localhost:3232/survey", List.class);
        return data;
    }

    public Employee findEmpById(String id) {
        try {
         List<Employee>data=getListEmployee();
                 for(Employee e1:data){
                     System.out.println(e1.getFirstName());
                 }
        }catch(Exception ex) {
            ex.printStackTrace();
        }
        return null;
    }
}


I am getting error in the console when I call method **findEmpById**

    java.lang.ClassCastException: class java.util.LinkedHashMap cannot be cast to class com.employeeService.dto.Employee (java.util.LinkedHashMap is in module java.base of loader 'bootstrap'; com.employeeService.dto.Employee is in unnamed module of loader 'app')

Employee class

@Getter
@Setter
@AllArgsConstructor
@NoArgsConstructor
@ToString
public class Employee {

    private String EmployeeID;
    private String FirstName;
    private String LastName;
    private String Gender;
    private Integer age;
    private String BusinessTravel;
    private String Department;
    private Integer DistanceFromHome_km;
    private String State;
    private String Ethnicity;
    private String Education;
    private String EducationField;
    private String JobRole;
    private String MaritalStatus;
    private Integer Salary;
    private Integer StockOptionLevel;
    private String OverTime;
    private Date HireDate;
    private String Attrition;
    private Integer YearsAtCompany;
    private Integer YearsInMostRecentRole;
    private Integer YearsSinceLastPromotion;
    private Integer YearsWithCurrManager;
    private String id;
}

Answer 1

you should use a different RestTemplate method, such as exchange, in this way:

ResponseEntity<List<Employee>> entity = restTemplate.exchange("http://localhost:3232/survey", HttpMethod.GET, null, new ParameterizedTypeReference<List<Employee>>() {});
List<String> data = entity.getBody();

In this way, you can tell how to map the collection of items that have to be deserialized in the response.