.../api/{id}/auth - работает =)

src/main/java/com/example/nto/service/impl/EmployeeServiceImpl.java

@@ -3,6 +3,7 @@ package com.example.nto.service.impl;
 import com.example.nto.entity.Employee;
 import com.example.nto.repository.EmployeeRepository;
 import com.example.nto.service.EmployeeService;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Component;
 import org.springframework.stereotype.Service;
 
@@ -20,6 +21,7 @@ import java.util.Optional;
 public class EmployeeServiceImpl implements EmployeeService {
     private final EmployeeRepository employeeRepository;
 
+    @Autowired
     public EmployeeServiceImpl(EmployeeRepository employeeRepository) {
         this.employeeRepository = employeeRepository;
     }
@@ -33,4 +35,8 @@ public class EmployeeServiceImpl implements EmployeeService {
     public Optional<Employee> getById(long id) {
         return employeeRepository.findById(id);
     }
+
+    public  boolean isIdValid(long id){
+        return employeeRepository.findById(id).isPresent();
+    }
 }