SpringBoot之业务逻辑层Service

一般，一个接口会调用业务逻辑层的一个方法，来实现该接口的具体业务逻辑和功能。

• 业务逻辑层需要编写接口

public interface StudentService {
    public List<Student> findByClass(Integer classId) throws Exception;
}

• 接口的实现类

@Service
public class StudentServiceImp implements StudentService {

    @Autowired
    private StudentRepository studentRepository;


    @Override
    public List<Student> findByClass(Integer classId) throws Exception {
        if (classId == null) {
            throw new IllegalArgumentException("Parameter classId can't be null.");  
        }
        return studentRepository.findByClassId(classId);
    }
}