java - 将blob图像转换为数组以在Spring MVC中显示在网页中

我正在尝试显示客户个人资料的图像。并且图像以blob类型存储在mysql中。我在休眠状态下使用spring mvc。我知道要显示blob类型的图像，我们必须转换为字节。我做了一定程度的努力。现在卡住了，无法显示任何图像。

  my controller:
   @RequestMapping(value="/myProfile.htm", method=RequestMethod.GET)

  public ModelAndView Profilelist(HttpServletRequest request,ModelMap model,Customer
 customer,Profile profile, HttpServletResponse response) throws SQLException ,
 Exception{
    //Profile profile = new Profile();

    String customerName = request.getUserPrincipal().getName();

    customer = customerService.getCustomerId(customerName);
    profile = profileService.getBycustomerId(customer);
    System.out.println("cust:  "+ customer);
    System.out.println("profile:  "+ profile);
    logger.error("Viewing Profile" +customerName);
    //Customer customer = new Customer();



    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    byte[] buf = new byte[1024];
    /*byte[] encodeBase64 = Base64.encodeBase64(buf);
    String base64Encoded = new String(encodeBase64, "UTF-8");
    ModelAndView mav = new ModelAndView();
    mav.addObject("profile", base64Encoded);*/
    Blob blob = profile.getContent();
    InputStream in = blob.getBinaryStream();
    System.out.println("id content" +in);
    int n = 0;
    while ((n=in.read(buf))>=0)
    {
       baos.write(buf, 0, n);

    }

    in.close();
    byte[] bytes = baos.toByteArray();
    System.out.println("bytes" +bytes);
    byte[] encodeBase64 = Base64.encodeBase64(buf);
    String base64Encoded = new String(encodeBase64, "UTF-8");
    ModelAndView mav = new ModelAndView();
    //mav.addObject("content", base64Encoded);
    customer.setEmailId(customerName);
    profile.setCustomer(customer);
    //profile.setContent(blob);
    System.out.println();
    profile = profileService.findProfileById(customer);
    model.addAttribute("content",base64Encoded);

    model.addAttribute("profile", profile);
    mav = new ModelAndView("myProfile");
    return mav;}

在jsp中我称它为

       <img  src= "data:image/jpeg;bytes,${profile.content}"/>

我的jsp是

     <form:form method="GET" modelAttribute="profile" action="myProfile.htm"
             enctype="multipart/form-data">


            <div class="containerdiv" align="center" >

                   <img  src= "data:image/jpeg;bytes,${content}"/>

                   </div>
   </form:form>

最佳答案

在数据库上保留Image Blob对象不是一个好习惯。只需将图像的文件名持久保存在db中，并将图像本身保存到特定路径即可。

我知道这不是您要的，但是如果您知道如何将照片上传到特定目录，并且由于使用的是Spring，则可以将其作为替代方法。

您为什么不创建一个控制器来为您读取图像。看到这个：

@Controller
public class ImageReadFile{

    // this is for mapping your image related path.
    @RequestMapping(value="/image/*")
    public void readImage(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        ServletContext sc = request.getServletContext();

        //here i uploaded my image in this path
        String imagePath = "/home/somefolder/Workspaces/Images/";
        String [] fragmentFilename = request.getServletPath().split("/");

        //Check if image isn't set
        if(fragmentFilename.length <= 2){
            return;
        }

        String filename = fragmentFilename[2];
        String requestedImage = "/"+filename;

        if(filename == null){
            response.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        File image = new File(imagePath, URLDecoder.decode(requestedImage, "UTF-8"));

        if(!image.exists()){
            response.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        String contentType = sc.getMimeType(image.getName());
        response.reset();
        response.setContentType(contentType);
        response.setHeader("Content-Length", String.valueOf(image.length()));
        Files.copy(image.toPath(), response.getOutputStream());
    }

}

这就是您要显示图像的方式

<img alt="${profile.filename}" src="${pageContext.request.contextPath}/image/${profile.filename}">

这就是我在Webapp中显示图像的方式。