postgresql - 在 Play 1.2.4 框架中显示 BLOB 图像

Question

我正在做这个项目，我必须存储用户的信息，包括他的图像。我将它作为 blob 图像存储在数据库中。如果“照片”是我的图像列，而不是当我在网页中呈现其他列时，例如：“render.column_name”它工作正常。但是当我为图像执行此操作时，例如“render.photo”，数据库在我的网页中返回“jpa.blob .....”。有人可以帮我如何显示存储在数据库中的这张图片吗？

Answer 1

You need a separate controller method to supply the image data. The controller could look like this, assuming you have some meta-information about the file, namely, the mime-type, here in a custom entity FileStore.

public class ShowFile extends Controller {
    public static void render(String id) {
        FileStore fs = // fetch the file out of the DB  using the id

        notFoundIfNull(fs);

        response.setContentTypeIfNotSet(fs.mimeType);
        response.setHeader("Cache-Control", "public, max-age=31536000");
        renderBinary(new ByteArrayInputStream(fs.content), fs.content.length);
    }
}

In the page you'll link to that method using the img tag:

<img src="@{ShowFile.render(image.id)}" />