无论如何缩放图像然后在jsp页面中显示？检索并显示图像时,我想显示所有相同尺寸的照片.是否有任何API可以做到这一点？我从谷歌搜索过,我发现的是关于使用takeit缩放图像,但无法在Web应用程序中使用.
最佳答案
你可以使用内置的Java 2D API(基本的Sun教程here).
基本上,您需要创建一个Servlet,它在doGet()方法中获取原始图像的InputStream,将其传递给Java 2D API,然后将其写入HTTP响应的OutputStream.然后,您只需将此Servlet映射到web.xml中的某个url-pattern,例如/ thumbs / *并在HTML< img>的src属性中调用此Servlet.元件.
这是一个基本的启动示例(您仍然需要自己按照自己的方式处理意外情况)：
protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException {
// First get image file name as request pathinfo (or parameter,whatever you want).
String imageFilename = request.getPathInfo().substring(1);
// And get the thumbnail dimensions as request parameters as well.
int thumbWidth = Integer.parseInt(request.getParameter("w"));
int thumbHeight = Integer.parseInt(request.getParameter("h"));
// Then get an InputStream of image from for example local disk file system.
InputStream imageInput = new FileInputStream(new File("/images",imageFilename));
// Now scale the image using Java 2D API to the desired thumb size.
Image image = ImageIO.read(imageInput);
BufferedImage thumb = new BufferedImage(thumbWidth,thumbHeight,BufferedImage.TYPE_INT_RGB);
Graphics2D graphics2D = thumb.createGraphics();
graphics2D.setBackground(Color.WHITE);
graphics2D.setPaint(Color.WHITE);
graphics2D.fillRect(0,thumbWidth,thumbHeight);
graphics2D.setRenderingHint(RenderingHints.KEY_INTERPOLATION,RenderingHints.VALUE_INTERPOLATION_BILINEAR);
graphics2D.drawImage(image,null);
// Write the image as JPG to the response along with correct content type.
response.setContentType("image/jpeg");
ImageIO.write(thumb,"JPG",response.getOutputStream());
}
使用web.xml映射的servlet如下：
这可以使用如下：
注意：不,这不能单独使用JSP,因为它是一种不适合此任务的视图技术.
