Spring BootData：增删改查操作的通用服务类

使用Spring Boot和Spring Data的通用服务类可以简化数据库的增删改查操作。这个通用服务类提供了一组常用的方法，可以在不同的实体类中直接调用，从而减少了重复的代码编写。

java
public abstract class BaseService {
    @Autowired
    protected JpaRepository repository;
    public T save(T entity) {
        return repository.save(entity);
    }
    public Iterable saveAll(Iterable entities) {
        return repository.saveAll(entities);
    }
    public T findById(ID id) {
        Optional optional = repository.findById(id);
        return optional.orElse(null);
    }
    public boolean existsById(ID id) {
        return repository.existsById(id);
    }
    public Iterable findAll() {
        return repository.findAll();
    }
    public long count() {
        return repository.count();
    }
    public void deleteById(ID id) {
        repository.deleteById(id);
    }
    public void delete(T entity) {
        repository.delete(entity);
    }
    public void deleteAll(Iterable entities) {
        repository.deleteAll(entities);
    }
    public void deleteAll() {
        repository.deleteAll();
    }
}

java
@Entity
@Table(name = "users")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;
    private int age;
    // getters and setters
}
@Repository
public interface UserRepository extends JpaRepository {
}
@Service
public class UserService extends BaseService {
    // 可以在这里添加一些特定的方法
}

java
@Service
public class ExampleService {
    @Autowired
    private UserService userService;
    public void createUser(String name, int age) {
        User user = new User();
        user.setName(name);
        user.setAge(age);
        userService.save(user);
    }
}