Spring控制器方法中的所有操作都是同一个Transaction的一部分吗？

Question

这是控制器类中的控制器方法

@ApiOperation(value="Create a new employee")
            @ApiResponses({})
            @RequestMapping(value= "/createEmployee",method= RequestMethod.POST)
            public Callable<EmployeeDTO> createEmployee(
                    HttpServletRequest request,

                    @RequestBody @Valid final EmployeeDTO employeeDto) {
               long employeeId = employeeService.createEmployee(employeeDto);
              EmployeeDTO createdEmployee = employeeService.getEmployee(employeeId);
return () -> createdEmployee;
    }

这是服务类

中createEmployee（employeeDto）的方法

   @Transactional
    public long createEmployee(employeeDto){
            Employee employee = new Employee();
            employee.setName(employeeDto.getName());
            employee.setCompanyId(employeeDto.getCompanyId());
            Employee savedEmployee = employeeRepository.save(employee);
            return savedEmployee.getEmployeeId();
    }

这是与上面相同的服务类中的getEmployee方法。

public EmployeeDTO getEmployee(long employeeId) {

        Employee employee = employeeRepository.findByEmployeeId(employeeId);

       EmployeeDTO employeeDTO = new EmployeeDTO();
       employeeDTO.setEmployeeId(employee.getEmployeeId());
       employeeDTO.setName(employee.getName());
   employeeDTO.setCompanyByCompanyId(employee.getCompanyByCompanyId());
    }

在上面的代码中，只有在控制器方法完成执行后，才会持久保存employee对象吗？ 在调试期间，我看到它正在插入数据库中。但是，在访问引用的实体对象时，employee.getCompanyByCompanyId()显示为NULL。所以我不确定它是否因为持久性没有正确发生或者是其他原因。请帮忙。

以下是实体类

 @Entity
        @Table(name = "employees")
        public class Employee {
            private long employeeId;
            private String name;
            private long companyId;
            private Company companyByCompanyId;

            @Id
            @GeneratedValue(strategy = GenerationType.IDENTITY)
            @Column(name = "employee_id")
            public long getEmployeeId() {
                return employeeId;
            }

            public void setEmployeeId(long employeeId) {
                this.employeeId = employeeId;
            }

            @Basic
            @Column(name = "name")
            public String getName() {
                return name;
            }

            public void setName(String name) {
                this.name = name;
            }

         @Basic
        @Column(name = "company_id")
        public long getCompanyId() {
            return companyId;
        }

        public void setCompanyId(long companyId) {
            this.companyId = companyId;
        }

            @ManyToOne
            @JoinColumn(name = "company_id", referencedColumnName = "company_id", nullable = false, insertable = false, updatable = false)
            public Company getCompanyByCompanyId() {
                return companyByCompanyId;
            }

            public void setCompanyByCompanyId(Company companyByCompanyId) {
                this.companyByCompanyId = companyByCompanyId;
            }
        }

和公司实体类如下

@Entity
@Table(name = "companies")
public class Company {
    private long companyId;
    private String companyName;
    private Collection<Employee> employeesByCompanyId;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "company_id")
    public long getCompanyId() {
        return companyId;
    }

    public void setCompanyId(long companyId) {
        this.companyId;
    }

    @Basic
    @Column(name = "company_name")
    public String getCompanyName() {
        return companyName;
    }

    public void setCompanyName(String companyName) {
        this.companyName = companyName;
    }

    @OneToMany(mappedBy = "companyByCompanyId")
    public Collection<Employee> getEmployeesByCompanyId() {
        return employeesByCompanyId;
    }

    public void setEmployeesByCompanyId(Collection<Employee> employeesByCompanyId) {
        this.employeesByCompanyId = employeesByCompanyId;
    }
}   

public interface ExmployeeRepository extends JpaRepository<Employee,Long>, JpaSpecificationExecutor<Employee> {

    Employee findByEmployeeId(long employeeId);
}