PNG在spring mapping中生成的图像不适用于apache FOP生成的PDF

Question

首先，这不是像这个链接中的情况

Java Applet中的Apache FOP-未找到数据的ImagePreloader

由于所有图像（包括PNG）都正常显示，除了由Spring映射动态生成的图像。

所以，也就是说，我有以下情况。我有一个带有这个映射的控制器：

    @GetMapping(value = {
        "/static/test/qr.png"
    }, produces = MediaType.IMAGE_PNG_VALUE)
    public void genericQR(HttpServletRequest request, HttpServletResponse response) throws WriterException, IOException {
        response.setContentType("image/png");
        final byte[] bytes = new QrCodeGenerator().generate("HELLO", null);
        response.setContentLength(bytes.length);
        response.getOutputStream().write(bytes);
    }

QrCodeGenerator类如下:

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.WriterException;
import com.google.zxing.client.j2se.MatrixToImageConfig;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;

/**
 *
 * @author jpaoletti
 */
public class QrCodeGenerator {

    private final int width;
    private final int height;

    public QrCodeGenerator() {
        width = 400;
        height = 400;
    }

    public QrCodeGenerator(int width, int height) {
        this.width = width;
        this.height = height;
    }

    public byte[] generate(String content, String logo) throws WriterException, IOException {
        // Create new configuration that specifies the error correction
        Map<EncodeHintType, ErrorCorrectionLevel> hints = new HashMap<>();
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);

        QRCodeWriter writer = new QRCodeWriter();
        BitMatrix bitMatrix = null;
        ByteArrayOutputStream os = new ByteArrayOutputStream();

        // Create a qr code with the url as content and a size of WxH px
        bitMatrix = writer.encode(content, BarcodeFormat.QR_CODE, width, height, hints);

        // Load QR image
        BufferedImage qrImage = MatrixToImageWriter.toBufferedImage(bitMatrix, getMatrixConfig());

        // Load logo image
        BufferedImage overly = logo == null ? null : getOverly(logo);

        // Calculate the delta height and width between QR code and logo
        int deltaHeight = overly == null ? null : (qrImage.getHeight() - overly.getHeight());
        int deltaWidth = overly == null ? null : (qrImage.getWidth() - overly.getWidth());

        // Initialize combined image
        BufferedImage combined = new BufferedImage(qrImage.getHeight(), qrImage.getWidth(), BufferedImage.TYPE_INT_ARGB);
        Graphics2D g = (Graphics2D) combined.getGraphics();

        // Write QR code to new image at position 0/0
        g.drawImage(qrImage, 0, 0, null);
        g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 1f));
        if (overly != null) {
            g.drawImage(overly, (int) Math.round(deltaWidth / 2), (int) Math.round(deltaHeight / 2), null);
        }
        ImageIO.write(combined, "png", os);
        return os.toByteArray();
    }

    private BufferedImage getOverly(String LOGO) throws IOException {
        URL url = new URL(LOGO);
        return ImageIO.read(url);
    }

    private MatrixToImageConfig getMatrixConfig() {
        // ARGB Colors
        // Check Colors ENUM
        return new MatrixToImageConfig(QrCodeGenerator.Colors.BLACK.getArgb(), QrCodeGenerator.Colors.WHITE.getArgb());
    }

    public enum Colors {

        BLUE(0xFF40BAD0),
        RED(0xFFE91C43),
        PURPLE(0xFF8A4F9E),
        ORANGE(0xFFF4B13D),
        WHITE(0xFFFFFFFF),
        BLACK(0xFF000000);

        private final int argb;

        Colors(final int argb) {
            this.argb = argb;
        }

        public int getArgb() {
            return argb;
        }
    }
}

从网站或浏览器直接访问图像很好，但尝试将其包含在apache fop生成的pdf中会引发以下错误：

2021/09/29 09:08:47 [http-nio-8084-exec-73] ERROR org.apache.fop.apps.FOUserAgent  - Image not available. URI: http://localhost:8084/static/test/qr.png. Reason: org.apache.xmlgraphics.image.loader.ImageException: The file format is not supported. No ImagePreloader found for http://localhost:8084/static/test/qr.png (No context info available)
org.apache.xmlgraphics.image.loader.ImageException: The file format is not supported. No ImagePreloader found for http://localhost:8084/static/test/qr.png
    at org.apache.xmlgraphics.image.loader.ImageManager.preloadImage(ImageManager.java:181)
    at org.apache.xmlgraphics.image.loader.cache.ImageCache.needImageInfo(ImageCache.java:127)
    at org.apache.xmlgraphics.image.loader.ImageManager.getImageInfo(ImageManager.java:123)

我试过很多选项，甚至换成JPG也有同样的结果。有什么想法吗？

本工程

  <fo:block>
   <fo:external-graphic src="url('{$url-base}/static/img/logosite.png')" content-height="scale-to-fit" height="1cm" />
  </fo:block>

这行不通

  <fo:block font-size="10pt" margin-top="0cm">
    <fo:external-graphic src="url('{$url-base}/static/test/qr.png')" content-height="scale-to-fit" height="3cm" content-width="3cm" scaling="non-uniform" />
  </fo:block>

预先感谢

Answer 1

原来是一个安全问题。从浏览器我可以访问，但只是因为我已登录。如果我尝试在不登录的情况下获取图像，则会弹出安全错误。

所以，解决方案是利用控制器模式和安全性：http拦截url