将 byte[] 转换为图像并在 jsp 上显示 [英] Convert byte[] to image and display on jsp

问题描述

我正在尝试在 jsp 页面上显示上传的图片(现在是字节数组).现在，byte[] 列存在于数据库中，必须转换为图像.

I'm trying to display an uploaded picture (which is now a byte array) on a jsp page. Now, the byte[] column exists in the database and has to be converted to an image.

这是我一直在尝试的:

jsp页面部分表格:

<c:forEach var="user" items="${userList}">
    <tr>
        <td>${user.fileName}</td>
        <td>
            <img src="data:image/jpg;base64,${user.imageFile}" alt="No image">
        </td>

从 MultipartFile 对象中获取字节数组的控制器的一部分:

Part of the controller that takes an array of bytes from a MultipartFile object:

@RequestMapping(value = "/register", method = RequestMethod.POST)
    public ModelAndView userRegister(@ModelAttribute("user") @Valid User user, BindingResult result, ModelMap model, @RequestParam("fileData") MultipartFile fileData) throws Exception {

            if (!fileData.isEmpty() && fileData != null) {                

                byte[] bytes = fileData.getBytes();
                user.setFileName(fileData.getOriginalFilename());
                user.setImageFile(bytes);
            }
        }

如果需要任何其他信息，请告诉我.谢谢.

If any additional information is needed, please let me know. Thanks.

推荐答案

您可以向您的 User 添加瞬态 base64imageFile 属性.它将保存图像的 base64 编码字符串，您可以像在 jsp 中访问它

You can add a tranisent base64imageFile property to your User. It will hold the base64 encoded string of the image, which you can access in your jsp like

<img alt="img" src="data:image/jpeg;base64,${user.base64imageFile}"/>

在你的方法中你应该进行编码，比如

And in your method you should do the encoding, somethig like

@RequestMapping(value = "/register", method = RequestMethod.POST)
    public ModelAndView userRegister(@ModelAttribute("user") @Valid User user, BindingResult result, ModelMap model, @RequestParam("fileData") MultipartFile fileData) throws Exception {
        if (!fileData.isEmpty() && fileData != null) {                
            byte[] bytes = fileData.getBytes();
            user.setFileName(fileData.getOriginalFilename());
            user.setImageFile(bytes);
            byte[] encodeBase64 = Base64.encodeBase64(bytes);
            String base64Encoded = new String(encodeBase64, "UTF-8");
            user.setBase64image(base64encoded);
        }
    }

IOUtils 和 Base64 是来自 org.apache.commons 的一个方便的 util 类，查找应该没有问题

IOUtils and Base64 are a handy util classes from org.apache.commons, shouldn't have a problem finding

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