Question

我正在构建一个小型图像缩放工具，用户首先将图像上传到网页，并在提交该表单时显示一个放大的图像以便保存。但是当用户发送对具有不同宽度和高度参数的相同图像的请求时，问题就出现了。在这种情况下，我在servlet中设置的内容disposing头似乎不起作用，第二个请求之后的图像仅与servlet的类名一起发送，而不是我在内容配置中提到的文件名和扩展名报头中。

response.setContentType("image/jpeg");
response.setHeader("Content-disposition","inline;filename="+filename);

我也尝试在编写器本身硬编码，但我使用的那个似乎没有任何文件名参数

private void doDownload(HttpServletResponse resp, BufferedImage bump,
            InputStream filecontent) throws IOException {

        //http://stackoverflow.com/questions/9340569/jpeg-image-with-wrong-colors
        OutputStream out = resp.getOutputStream();
        Iterator<ImageWriter> iter = ImageIO
                .getImageWritersByMIMEType("image/jpeg");
        ImageWriter writer = iter.next();
        ImageWriteParam iwp = writer.getDefaultWriteParam();
        iwp.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
        iwp.setCompressionQuality(1);
        ImageOutputStream imgOut = new MemoryCacheImageOutputStream(out);
        writer.setOutput(imgOut);
        IIOImage image = new IIOImage(bump, null, null);
        writer.write(null, image, iwp);
        out.flush();
        out.close();
        writer.dispose();

    }

有什么办法可以在将图像文件名写入输出流时设置它的文件名吗？

Answer 1

在此Class中声明一个Static Integer变量。

private static int fileno=0;


private void doDownload(HttpServletResponse resp, BufferedImage bump,
            InputStream filecontent) throws IOException {

Iterator iter = ImageIO.getImageWritersByFormatName("jpeg");
ImageWriter writer = (ImageWriter)iter.next();
ImageWriteParam iwp = writer.getDefaultWriteParam();
iwp.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
iwp.setCompressionQuality(1);
String OUTPUTFILE = "C:/Users/Harish/Desktop/jpegFile"+fileno++;
File file = new File(OUTPUTFILE);
//Your fileName will be jpegFile0; and next time jpegFile1 and so on.
FileImageOutputStream imgOut = new FileImageOutputStream(file);
writer.setOutput(imgOut);
IIOImage image = new IIOImage(bump, null, null);
writer.write(null, image, iwp);
writer.dispose();

 }

内容 - 处置标头无法正常工作

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