java - 从图像 URL 将图像保存到 MySql (Spring JPA Hibernate)

Question

我正在工作 Spring JPA Hibernate 项目，想要将图像从 Image Url 保存到 Mysql 数据库。我正在传递订单 DTO 数据以及从 Rest 服务获取的图像 URL。如何将图像 url 作为图像保存到数据库。我认为我们必须首先从 Url 获取图像。请解决这个问题。

订单DO.java

@Table(name = "ORDER")
public class OrderDO  implements Serializable{

    @Column(name = "ORDER_NUMBER", nullable = false)
    private String orderNumber; 

    @OneToMany(cascade = CascadeType.ALL, mappedBy="order")
    private Set<OrderItemDO> items = new HashSet<>();
}

OrderItemDO.java

@Table(name = "ORDER_ITEM")
public class OrderItemDO implements Serializable{   

    @Column(name = "PRODUCT_NAME",nullable = false)
    private String name;

    @Lob
    @Column(name = "IMAGE")
    private byte[] image;

    @ManyToOne(cascade=CascadeType.ALL)
    @JoinColumn(name="ORDER_ID", referencedColumnName="ID")
    private OrderDO order;
}

OrderRepository.java

@Repository
public interface OrderRepository extends CrudRepository<OrderDO, Long>{

    public Page<OrderDO> findAll(Pageable pageable);    

}

OrderServiceImpl.java

public class OrderServiceImpl {

    @Autowired
    private ModelMapper modelMapper;

    @Autowired
    private OrderRepository orderRepository;

    private OrderDO map(Order dto) {
        OrderDO orderDO =  modelMapper.map(dto, OrderDO.class);

        Set<OrderItemDO> itemsDO = new HashSet<>();
        for(OrderItem item : dto.getItems()) {
            OrderItemDO itemDO = map(item);
            itemDO.setOrder(orderDO);
            itemsDO.add(itemDO);
        }
        orderDO.setItems(itemsDO);      
        return orderDO; 
    }

    public OrderItemDO map(OrderItem dto) {
        OrderItemDO itemDO = modelMapper.map(dto, OrderItemDO.class);
        return itemDO;
    }

    public Order SaveOrder(Order dto) {
        OrderDO entity = this.map(dto);
        entity = orderRepository.save(entity);
        return this.map(entity);
    }

Answer 1

您可以在Rest Service中将图像url转换为数据byte[]图像，然后再保存。

public static byte[] convertImageByte(URL url) throws IOException {

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        InputStream is = null;
        try {
            is = url.openStream ();
            byte[] byteChunk = new byte[4096]; // Or whatever size you want to read in at a time.
            int n;

            while ( (n = is.read(byteChunk)) > 0 ) {
                baos.write(byteChunk, 0, n);
            }
            return byteChunk;
        }
        catch (IOException e) {
            System.err.printf ("Failed while reading bytes from %s: %s", url.toExternalForm(), e.getMessage());
            e.printStackTrace ();
            // Perform any other exception handling that's appropriate.
        }
        finally {
            if (is != null) { is.close(); }
        }
        return null;
    }