使用Apache FOP的SVG到PDF

Question

我有3个SVG文件，我想转换成一个PDF。我正试图用Apache FOP实现这一点，但迄今为止我没有成功。

我的想法是简单地将所有3个SVG文件一个接一个地写入生成的PDF中，但是这不起作用。我的代码是这样的:

public void convertSVG2PDF(File svg, File svg2, File svg3, File pdf) throws IOException,
        TranscoderException {

    // Create transcoder
    Transcoder transcoder = new PDFTranscoder();
    // Transcoder transcoder = new org.apache.fop.render.ps.PSTranscoder();

    // Setup input
    InputStream in = new java.io.FileInputStream(svg);
    InputStream in2 = new java.io.FileInputStream(svg2);
    InputStream in3 = new java.io.FileInputStream(svg3);

    try {
        TranscoderInput input = new TranscoderInput(in);
        TranscoderInput input2 = new TranscoderInput(in2);
        TranscoderInput input3 = new TranscoderInput(in3);

        // Setup output
        OutputStream out = new java.io.FileOutputStream(pdf);
        out = new java.io.BufferedOutputStream(out);
        try {
            TranscoderOutput output = new TranscoderOutput(out);
            TranscoderOutput output2 = new TranscoderOutput(out);
            TranscoderOutput output3 = new TranscoderOutput(out);

            // Do the transformation
            transcoder.transcode(input, output);
            transcoder.transcode(input2, output2);
            transcoder.transcode(input3, output3);
        } finally {
            out.close();
        }
    } finally {
        in.close();
    }
}

最后，我的SVG图像如下所示，它们是由javascript应用程序生成的。

< svg height="70" id="topBar" version="1.1" width="1060" xmlns="http://www.w3.org/2000/svg">
    <g clip-path="url(#clip)" height="560" transform="translate(60,0)" width="1060">
      <clipPath id="clip">
        <rect height="70" width="1000"/>
  </clipPath>
  <rect fill="white" fill-opacity="1" height="70" id="rect" stroke="black" stroke-width="2" width="1000" x="0" y="0"/>
  <path d="M-35.63129521110456,34L-1.6312952111045584,68L32.36870478889544,34L-1.6312952111045584,1Z" fill="white" id="mileStones" stroke="green" stroke-width="2"/>
  <path d="M269.4286615414018,34L303.4286615414018,68L337.4286615414018,34L303.4286615414018,1Z" fill="white" id="mileStones" stroke="green" stroke-width="2"/>
  <path d="M674.5082762455497,34L708.5082762455497,68L742.5082762455497,34L708.5082762455497,1Z" fill="white" id="mileStones" stroke="green" stroke-width="2"/>
  <text id="mileStoneText" style="font-size: 15px;" x="-16.631295211104558" y="40">MS1</text>
  <text id="mileStoneText" style="font-size: 15px;" x="288.4286615414018" y="40">MS2</text>
  <text id="mileStoneText" style="font-size: 15px;" x="693.5082762455497" y="40">MS3</text>
</g>

到目前为止，我的代码覆盖了pdf两次，生成的PDF只包含最后一个SVG。我也可以用里面的图像创建3个单独的pdf。但我需要这三个都在一页上，一个在另一个下面。

Answer 1

您可以使用PDFMergerU的合并您的PDF。以下是一些基于您的代码的示例代码：

public class SvgToPdfConverter {

    private ArrayList<byte[]> pdfs = new ArrayList<byte[]>();

    public void convertSVG2PDF(File svg) throws IOException, TranscoderException {
        // Create transcoder
        Transcoder transcoder = new PDFTranscoder();
        // Input
        FileInputStream bais = new FileInputStream(svg);
        // Output
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        TranscoderInput input = new TranscoderInput(bais);
        TranscoderOutput output = new TranscoderOutput(baos);
        // Do the transformation
        transcoder.transcode(input, output);
        pdfs.add(baos.toByteArray());
    }

    public void merge(File mergedPDF) throws IOException, COSVisitorException {
        PDFMergerUtility ut = new PDFMergerUtility();
        for (byte[] bytes : pdfs) {
            ut.addSource(new ByteArrayInputStream(bytes));
        }
        ut.setDestinationStream(new FileOutputStream(mergedPDF));
        ut.mergeDocuments();
    }
}

还有一个 main 方法的示例：

    public static void main(String[] args) {
        File exampleSVGFile = new File(System.getProperty("user.home") + File.separator + "example.svg");
        File exampleOutputFile = new File(System.getProperty("user.home") + File.separator + "example.pdf");
        SvgToPdfConverter converter = new SvgToPdfConverter();
        try {
            converter.convertSVG2PDF(exampleSVGFile);
            converter.convertSVG2PDF(exampleSVGFile);
            converter.convertSVG2PDF(exampleSVGFile);
        } catch (Exception e) {
            log.error("Converting svg failed. ", e);
        }
        try {
            converter.merge(exampleOutputFile);
        } catch (Exception e) {
            log.error("Merge failed. ", e);
        }
    }