如何使用 xsl FO 在 pdf 中打印数组

Question

我有一组对象，我想以模板格式打印为 pdf。 我尝试使用下面的代码将集合打印为 PDF，但在创建文件后我看不到任何以 PDF 呈现的文本。

java代码如下：

FopFactory fopFactory = FopFactory.newInstance();
OutputStream out = new BufferedOutputStream(new FileOutputStream(new File("/home/myfile.pdf")));
try {
Fop fop = fopFactory.newFop(MimeConstants.MIME_PDF, out);
TransformerFactory factory = TransformerFactory.newInstance();
Transformer transformer = factory.newTransformer(); 
    Eden[] ed=new Eden[3];
    for(int i=0;i<ed.length;i++)
    {
        ed[i]=new Eden();
    ed[i].setBlow(String.valueOf(i));
    }
Source src = new StreamSource(new File("/home/tables.fo"));
Result res = new SAXResult(fop.getDefaultHandler());
transformer.setParameter("dep", ed);
transformer.transform(src, res);
} finally {
out.close();
}

fo文件如下：

<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format" 
 xmlns:xsl="http://www.w3.org    /1999/XSL/Transform">
   <fo:layout-master-set>
    <fo:simple-page-master master-name="my-page">
  <fo:region-body margin="0.5in"/>
</fo:simple-page-master>
 </fo:layout-master-set>
  <fo:page-sequence master-reference="my-page">
 <fo:flow flow-name="xsl-region-body" font="7pt Times">
    <fo:block border="thin solid black" text-align="center">
    <xsl:for-each select="dep">
        {$blow}
    </xsl:for-each>
</fo:block>
 </fo:flow>
  </fo:page-sequence>
</fo:root>

Answer 1

无法使用 XSL-F(ormatting)O(bjects) 输出值。 example you're using 实际上并没有进行 XSLT 转换，这是能够将值传递到样式表所必需的。

以下代码将执行您想要的操作，与您的代码的唯一区别是 XSLT 转换：

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.io.FileOutputStream;

import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.sax.SAXResult;
import javax.xml.transform.stream.StreamSource;

import org.apache.fop.apps.FOPException;
import org.apache.fop.apps.Fop;
import org.apache.fop.apps.FopFactory;
import org.apache.fop.apps.MimeConstants;


public class test {

    public static void main(String[] args) throws FOPException, TransformerException, IOException 
    {
    /*..*/

     // Step 1: Construct a FopFactory
     // (reuse if you plan to render multiple documents!)
     FopFactory fopFactory = FopFactory.newInstance();

     // Step 2: Set up output stream.
     // Note: Using BufferedOutputStream for performance reasons (helpful with FileOutputStreams).
     OutputStream out = new BufferedOutputStream(new FileOutputStream(new File("F:/myfile.pdf")));

     try 
     {
        // Step 3: Construct fop with desired output format
        Fop fop = fopFactory.newFop(MimeConstants.MIME_PDF, out);

        // Step 5: Setup input and output for XSLT transformation
        // Setup input stream

        Source xsltSource = new StreamSource(new File("F:/myfile.xsl"));
        TransformerFactory transformerFactory = TransformerFactory.newInstance();
        Transformer transformer = transformerFactory.newTransformer(xsltSource);

        int[] array = {1,2,3};
        transformer.setParameter("test", "1234");
        transformer.setParameter("testRaw", array);

        // Resulting SAX events (the generated FO) must be piped through to FOP
        Result res = new SAXResult(fop.getDefaultHandler());

        transformer.transform(xsltSource, res);

     } 
     finally 
     {
         out.close();
     }
    }

}

现在，要在 XSL 样式表中使用该参数（对我来说是 myfile.xsl），它必须如下所示：

<xsl:stylesheet version="2.0" xmlns:fo="http://www.w3.org/1999/XSL/Format" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:param name="test"/>
    <xsl:param name="testRaw"/>
    <xsl:template match="/">
        <fo:root>
           <fo:layout-master-set>
            <fo:simple-page-master master-name="my-page">
          <fo:region-body margin="0.5in"/>
        </fo:simple-page-master>
         </fo:layout-master-set>
          <fo:page-sequence master-reference="my-page">
         <fo:flow flow-name="xsl-region-body" font="7pt Times">
            <fo:block border="thin solid black" text-align="center">
                <xsl:value-of select="$test"/>
            </fo:block>
            <fo:block break-before="page" border="thin solid black" text-align="center">
                <xsl:value-of select="$testRaw"/>
            </fo:block>
         </fo:flow>
          </fo:page-sequence>
        </fo:root>
    </xsl:template>
</xsl:stylesheet>

此样式表定义了两个参数：“test”和“testRaw”，它们都输出到两个单独的页面。 为此，您可以使用<xsl:value-of select="$paramName"/>。

在我发布的代码中，这两个值是一个字符串和一个 int 数组。 请注意：您将不能将任何类传递给样式表并期望 XSL 转换器知道它。这行不通。通常，传递给样式表的参数被视为字符串值。 If you pass anything else, you need to make sure your stylesheet and transformer can actually handle it.

在你的机器上运行代码，看看第二页写了什么：这只是胡言乱语，因为样式表和转换器无法处理 int 数组。如果您确实需要处理来自自定义类的数据，我建议将您真正需要的值作为（连接的）字符串传递给样式表。