java - itext 使用 Java 在 pdf 中创建 XMP

Question

我需要在 java 中(使用 itext)创建以下 xmp 元数据并将其放入我的一个 pdf 中。

<rdf:Description rdf:about="" xmlns:pdfaExtension="http://www.aiim.org/pdfa/ns/extension/" xmlns:pdfaSchema="http://www.aiim.org/pdfa/ns/schema#" xmlns:pdfaProperty="http://www.aiim.org/pdfa/ns/property#" xmlns:pdfaType="http://www.aiim.org/pdfa/ns/type#" xmlns:pdfaField="http://www.aiim.org/pdfa/ns/field#"> <pdfaExtension:schemas>
<rdf:Bag>
<rdf:li rdf:parseType="Resource">
<pdfaSchema:schema>ABI Assegni Schema</pdfaSchema:schema> <pdfaSchema:namespaceURI>http://abi.it/std/cheque/xmlns</pdfaSchema:namespaceURI> <pdfaSchema:prefix>assegni</pdfaSchema:prefix>
<pdfaSchema:property>
    <rdf:Seq>
<rdf:li rdf:parseType="Resource">
<pdfaProperty:name>IDDocumento</pdfaProperty:name> <pdfaProperty:valueType>Text</pdfaProperty:valueType> <pdfaProperty:category>external</pdfaProperty:category> <pdfaProperty:description>Identificativo univoco del documento</pdfaProperty:description>
</rdf:li>
<rdf:li rdf:parseType="Resource">
<pdfaProperty:name>datachiusura</pdfaProperty:name> <pdfaProperty:valueType>Date</pdfaProperty:valueType> <pdfaProperty:category>external</pdfaProperty:category> <pdfaProperty:description>Data e ora della produzione del file</pdfaProperty:description>
</rdf:li>
<rdf:li rdf:parseType="Resource">
<pdfaProperty:name>oggettodocumento</pdfaProperty:name> <pdfaProperty:valueType>Text</pdfaProperty:valueType> <pdfaProperty:category>external</pdfaProperty:category> <pdfaProperty:description>Oggetto del documento</pdfaProperty:description>
</rdf:li>
<rdf:li rdf:parseType="Resource">
<pdfaProperty:name>soggettoproduttore</pdfaProperty:name> <pdfaProperty:valueType>soggetto</pdfaProperty:valueType> <pdfaProperty:category>external</pdfaProperty:category> <pdfaProperty:description>Soggetto produttore</pdfaProperty:description>
</rdf:li>
<rdf:li rdf:parseType="Resource">
<pdfaProperty:name>destinatario</pdfaProperty:name> <pdfaProperty:valueType>soggetto</pdfaProperty:valueType> <pdfaProperty:category>external</pdfaProperty:category> <pdfaProperty:description>Destinatario</pdfaProperty:description>
</rdf:li> </rdf:Seq>

</pdfaSchema:property>
</rdf:li>
</rdf:Bag>
</pdfaExtension:schemas>
</rdf:Description>

到目前为止，我尝试了这部分代码:

PdfReader reader = new PdfReader(baos.toByteArray());
        PdfAStamper stamper = new PdfAStamper(reader, baos,     PdfAConformanceLevel.PDF_A_1B);

        String namespaceExtension = new    String("http://www.aiim.org/pdfa/ns/extension/");
        String namespaceSchema = new String("http://www.aiim.org/pdfa/ns/schema#");
        String namespaceProperty = new String("http://www.aiim.org/pdfa/ns/property#");
        String namespaceType = new String("http://www.aiim.org/pdfa/ns/type#");
        String namespaceField = new String("http://www.aiim.org/pdfa/ns/field#");
        XMPSchemaRegistry registry = XMPMetaFactory.getSchemaRegistry();
        registry.registerNamespace(namespaceExtension, "pdfaExtension");
        registry.registerNamespace(namespaceSchema, "pdfaSchema");
        registry.registerNamespace(namespaceProperty, "pdfaProperty");
        registry.registerNamespace(namespaceType, "pdfaType");
        registry.registerNamespace(namespaceField, "pdfaField");

        XmpWriter w = new XmpWriter(baos);
        w.appendArrayItem(namespaceExtension, "schemas", "a");

        w.close();

        writer.setXmpMetadata(baos.toByteArray());

创建的xmp如下:

<pdfaExtension:schemas>
    <rdf:Bag>
      <rdf:li>a</rdf:li>
    </rdf:Bag>

现在我无法理解如何继续。关于如何执行此操作的任何想法？

提前致谢

Answer 1

我能够用 iText5 来回答这个问题，尽管我认为这个答案有点“hack”，因为它没有使用任何 iText 语义元数据对象，其中大部分似乎是已弃用。请特别注意，xmp.DublinCoreSchema、xmp.PdfSchema、xmp.XmpArray 和 xmp.XmpSchema 已弃用而 xmp.CustomSchema 不再存在。

iText 文档在这方面非常糟糕。

答案应该可用here或 here或 here但这些都没有帮助。它们只展示了如何操作信息部分。

一个解决方案可以从线程Adding & retrieve custom properties to PDF using XMP 中导出，但所有使用的 iText 类都已弃用。

最后，我注意到任何 XML 都可以通过stamper.setXmpMetadata(metadata) 插入，其中metadata 是一个 byte[] 包含 XML。这个 XML 可以用 DOM 创建，但在下面的快速和脏中使用一个文件。

package itext.sandpit;

import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.Paragraph;
import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.PdfStamper;
import com.itextpdf.text.pdf.PdfWriter;
import com.itextpdf.xmp.XMPException;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;


public class ItextSandpit {

    public static void main(String[] args) throws DocumentException,
            IOException,
            XMPException {

        // Create PDF
        Document document = new Document();
        PdfWriter.getInstance(
                document, new FileOutputStream("mypdf.pdf"));
        document.open();
        document.add(new Paragraph("Hello World!"));
        document.close();

        // Read metadata
        File fff = new File("metadata.xml");
        FileInputStream fileInputStream = new FileInputStream(fff);
        int byteLength = (int) fff.length(); //bytecount of the file-content
        byte[] metadatabytes = new byte[byteLength];
        fileInputStream.read(metadatabytes, 0, byteLength);

        // Add metadata
        PdfReader reader = new PdfReader("mypdf.pdf");
        PdfStamper stamper = new PdfStamper(reader, new FileOutputStream("mypdf_plus_xmp.pdf"));

        stamper.setXmpMetadata(metadatabytes);
        stamper.close();
        reader.close();
    }

}

创建文件 metadata.xml 并将 OP 中的 XML 复制并粘贴到该文件中，然后运行。要确认元数据确实存在于创建的 PDF 中，pdfinfo -meta mypdf_plus_xmp.pdf 产生

Producer:       iText® 5.5.12 ©2000-2017 iText Group NV (AGPL-version); modified using iText® 5.5.12 ©2000-2017 iText Group NV (AGPL-version)
CreationDate:   Tue Oct 10 21:01:21 2017
ModDate:        Tue Oct 10 21:01:21 2017
Tagged:         no
UserProperties: no
Suspects:       no
Form:           none
JavaScript:     no
Pages:          1
Encrypted:      no
Page size:      595 x 842 pts (A4)
Page rot:       0
File size:      3224 bytes
Optimized:      no
PDF version:    1.4
Metadata:
<rdf:Description rdf:about="" xmlns:pdfaExtension="http://www.aiim.org/pdfa/ns/extension/" xmlns:pdfaSchema="http://www.aiim.org/pdfa/ns/schema#" xmlns:pdfaProperty="http://www.aiim.org/pdfa/ns/property#" xmlns:pdfaType="http://www.aiim.org/pdfa/ns/type#" xmlns:pdfaField="http://www.aiim.org/pdfa/ns/field#"> <pdfaExtension:schemas>
<rdf:Bag>
<rdf:li rdf:parseType="Resource">
<pdfaSchema:schema>ABI Assegni Schema</pdfaSchema:schema> <pdfaSchema:namespaceURI>http://abi.it/std/cheque/xmlns</pdfaSchema:namespaceURI> <pdfaSchema:prefix>assegni</pdfaSchema:prefix>
<pdfaSchema:property>
    <rdf:Seq>
<rdf:li rdf:parseType="Resource">
<pdfaProperty:name>IDDocumento</pdfaProperty:name> <pdfaProperty:valueType>Text</pdfaProperty:valueType> <pdfaProperty:category>external</pdfaProperty:category> <pdfaProperty:description>Identificativo univoco del documento</pdfaProperty:description>
</rdf:li>
<rdf:li rdf:parseType="Resource">
<pdfaProperty:name>datachiusura</pdfaProperty:name> <pdfaProperty:valueType>Date</pdfaProperty:valueType> <pdfaProperty:category>external</pdfaProperty:category> <pdfaProperty:description>Data e ora della produzione del file</pdfaProperty:description>
</rdf:li>
<rdf:li rdf:parseType="Resource">
<pdfaProperty:name>oggettodocumento</pdfaProperty:name> <pdfaProperty:valueType>Text</pdfaProperty:valueType> <pdfaProperty:category>external</pdfaProperty:category> <pdfaProperty:description>Oggetto del documento</pdfaProperty:description>
</rdf:li>
<rdf:li rdf:parseType="Resource">
<pdfaProperty:name>soggettoproduttore</pdfaProperty:name> <pdfaProperty:valueType>soggetto</pdfaProperty:valueType> <pdfaProperty:category>external</pdfaProperty:category> <pdfaProperty:description>Soggetto produttore</pdfaProperty:description>
</rdf:li>
<rdf:li rdf:parseType="Resource">
<pdfaProperty:name>destinatario</pdfaProperty:name> <pdfaProperty:valueType>soggetto</pdfaProperty:valueType> <pdfaProperty:category>external</pdfaProperty:category> <pdfaProperty:description>Destinatario</pdfaProperty:description>
</rdf:li> </rdf:Seq>

</pdfaSchema:property>
</rdf:li>
</rdf:Bag>
</pdfaExtension:schemas>
</rdf:Description>

如果可能，使用iText“包装器”，例如 PDFBox或移动到 iText7。