在MongoDB中用jsp春季显示图像 [英] Spring display image in jsp from MongoDB

问题描述

我需要从MongoDB GridFS系统获取图像，然后将其显示在JSP img标记中. 这是我的代码不起作用:

I need to get an image from MongoDB GridFS system, then displaying it in a JSP img tag. This is my code that isnt working:

@RequestMapping(value = "/getPhoto", method = RequestMethod.GET)
public @ResponseBody
void getPhoto(HttpServletRequest request,
        HttpServletResponse response) {
    try {
    System.out.println("getting photo...");
    GridFSDBFile imageForOutput = userFacade.loadProfilePhoto((User) SecurityContextHolder.getContext().getAuthentication()
            .getPrincipal());
    BufferedImage image = ImageIO.read(imageForOutput.getInputStream());
    byte[] imageBytes = ((DataBufferByte) image.getData().getDataBuffer()).getData();
    response.setHeader("expires", "0"); 
    response.setContentType("image/jpg");
    response.setContentLength(imageBytes.length);
    OutputStream out = response.getOutputStream();
    out.write(imageBytes, 0, imageBytes.length);
    out.flush();
    out.close();
    return;
    } catch (Exception e) {
        // TODO Auto-generated catch block
    }

首先我得到GridFSDBFile，然后我需要获得byte [].此后，我将其写入响应对象，但我不知道我是否正确地执行了操作.

Firstly i get the GridFSDBFile and then I need to get the byte[].After that i write it in the response object but i dont know if i am doing it correctly.

JSP中的代码如下:

The code in the JSP is as follows:

<c:url var="getPhoto" value="/settingsAdmin/getPhoto" />
<div id="preview">
   <img id="imagePreview" src="${getPhoto}" alt="Profile Photo"/>
</div>

最后，正确调用了控制器，但是错误必须在内部.

Finally, the controller is called correctly but the mistake must be inside it.

提前谢谢

推荐答案

最后，我自己达成了一个解决方案，我将其发布，以便其他人可以解决:

Finally i reached a solution by myself, i post it so others can work it out:

控制器部分

@RequestMapping(value = "/getPhoto", method = RequestMethod.GET)
public @ResponseBody
void getPhoto(HttpServletRequest request,
        HttpServletResponse response) {
    try {
            GridFSDBFile imageForOutput = userFacade.loadProfilePhoto((User) SecurityContextHolder.getContext().getAuthentication()
                    .getPrincipal());
            InputStream is = imageForOutput.getInputStream();
            ByteArrayOutputStream buffer = new ByteArrayOutputStream();
            int nRead;
            byte[] data = new byte[16384];
            while ((nRead = is.read(data, 0, data.length)) != -1) {
                buffer.write(data, 0, nRead);
            }
            buffer.flush();
            byte[]imagenEnBytes = buffer.toByteArray();


            response.setHeader("Accept-ranges","bytes");
            response.setContentType( "image/jpeg" );
            response.setContentLength(imagenEnBytes.length);
            response.setHeader("Expires","0");
            response.setHeader("Cache-Control","must-revalidate, post-check=0, pre-check=0");
            response.setHeader("Content-Description","File Transfer");
            response.setHeader("Content-Transfer-Encoding:","binary");

            OutputStream out = response.getOutputStream();
            out.write( imagenEnBytes );
            out.flush();
            out.close();
    } catch (Exception e) {
        // TODO Auto-generated catch block

    }

}

JSP视图

<c:url var="getPhoto" value="/settingsAdmin/getPhoto" />
<div id="preview">
    <img id="imagePreview" src="${getPhoto}"alt="Profile Photo"/>
</div>

谢谢大家的帮助

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