Java 将图像从图像URL保存到MySql（Spring JPA Hibernate）

我正在从事Spring JPA Hibernate项目，希望将图像从图像Url保存到Mysql数据库。我正在使用从Rest服务获取的图像URL将订单数据传递给数据。如何将图像URL作为图像保存到数据库。我想我们必须先从Url获取图像。请解决这个问题

OrderDO.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<>();
}

OrderRepository.java

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

    public Page<OrderDO> findAll(Pageable pageable);    

}

@存储库
公共接口OrderRepository扩展了Crudepository{
公共页面findAll（可分页）；
}

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);
    }

公共类OrderServiceImpl{ @自动连线 私有模型映射器模型映射器； @自动连线 专用医嘱存储库医嘱存储库； 专用OrderDO映射（订单dto）{ OrderDO OrderDO=modelMapper.map（dto，OrderDO.class）； Set itemsDO=new HashSet（）； 对于（OrderItem项：dto.getItems（））{ OrderItemDO itemDO=映射（项目）； itemDO.setOrder（orderDO）； 项目DO.add（项目DO）； } orderDO.setItems（itemsDO）； 退货订单； } 公共OrderItemDO映射（OrderItemDTO）{ OrderItemDO itemDO=modelMapper.map（dto，OrderItemDO.class）； 返回itemDO； } 公共秩序保存令（订单dto）{ OrderDO entity=this.map（dto）； 实体=orderRepository.save（实体）； 返回此.map（实体）； }

---

在保存图像之前，您可以在Rest服务中将图像url转换为数据字节[]图像

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;
    }

---

确定问题已解决。下面是将图像Url转换为字节数组的代码。请参阅此问题的更多答案

public static byte[] convertImageByte(URL url) throws IOException {
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    InputStream is = null;
    try {
        is = new BufferedInputStream(url.openStream());
        byte[] byteChunk = new byte[4096];
        int n;
        while ( (n = is.read(byteChunk)) > 0 ) {
            baos.write(byteChunk, 0, n);
        }   
        return baos.toByteArray();
    }
    catch (IOException e) {e.printStackTrace ();}
    finally {
        if (is != null) { is.close(); }
    }
    return null;
}

将Dto保存到数据库时

if(dto.getImageUrl() != null) {             
    try {
    URL imageUrl = new URL(dto.getImageUrl());
    itemDO.setImage(convertImageByte(imageUrl));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    entity = orderItemRepository.save(itemDO);

从数据库中获取图像

public byte[] getImageForOrderItem(long itemId) {
    Optional<OrderItemDO> option = orderItemRepository.findById(itemId);
    if(option.isPresent()) {
        OrderItemDO itemDO = option.get();
        if(itemDO.getImage() != null) {
            byte[] image = itemDO.getImage();
            return image;
        }
    }
    return null;
}

---

使用HTTP客户端下载图像，然后将其保存到databaseSystem.setProperty（“java.net.useSystemProxies”，“true”）；byte[]imageBytes=IOUtils.toByteArray（新URL（“”.openStream（））；

public byte[] getImageForOrderItem(long itemId) {
    Optional<OrderItemDO> option = orderItemRepository.findById(itemId);
    if(option.isPresent()) {
        OrderItemDO itemDO = option.get();
        if(itemDO.getImage() != null) {
            byte[] image = itemDO.getImage();
            return image;
        }
    }
    return null;
}

@GetMapping(path="/orderItem/image/{itemId}")
@ResponseStatus(HttpStatus.OK)
public void getImageForOrderItem(@PathVariable("itemId") long itemId, HttpServletResponse response) { 
    byte[] buffer = orderServiceImpl.getImageForOrderItem(itemId);
    if (buffer != null) {
        response.setContentType("image/jpeg");
        try {
            response.getOutputStream().write(buffer);
            response.getOutputStream().flush();
            response.getOutputStream().close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    } 
}