mybatis 延迟加载 代码示例

好的，关于mybatis延迟加载的代码示例，下面是一段示例代码：

public class User {
    private Long id;
    private String username;
    private List<Order> orders;

    // 省略构造方法和getter/setter方法

    public List<Order> getOrders() {
        return orders;
    }

    public void setOrders(List<Order> orders) {
        this.orders = orders;
    }
}

public interface UserMapper {
    User selectUserById(Long id);

    List<User> selectAllUsers();
}

public interface OrderMapper {
    List<Order> selectOrdersByUserId(Long userId);
}

SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();

SqlSession sqlSession = sqlSessionFactory.openSession();

UserMapper userMapper = sqlSession.getMapper(UserMapper.class);

User user = userMapper.selectUserById(1L);

List<Order> orders = user.getOrders();

// 这里不会触发orders属性的延迟加载，因为已经通过selectUserById方法一并取出了
// 然后可以在需要使用orders属性的地方进行延迟加载
if (orders == null) {
    OrderMapper orderMapper = sqlSession.getMapper(OrderMapper.class);
    orders = orderMapper.selectOrdersByUserId(user.getId());
    user.setOrders(orders);
}

注：以上示例代码仅供参考，具体实现可能会因项目架构和需求不同而有所变化。