Working with PDF File Metadata

Get PDF File Information

To get file-specific information about a PDF file, first get the DocumentInfo object using the Document class  getInfo(). Once the DocumentInfo object is retrieved, you can get the values of the individual properties.

The following code snippet shows you how to set PDF file information.

public class ExampleMetadata {

    private static String _dataDir = "/home/aspose/pdf-examples/Samples/Metadata/";

    public static void GetPDFFileInformation() {
        // Create a new PDF document
        Document pdfDocument = new Document(_dataDir + "sample.pdf");
        // Get document information
        DocumentInfo docInfo = pdfDocument.getInfo();
        // Show document information
        System.out.println("Author: " + docInfo.getAuthor());
        System.out.println("Creation Date: " + docInfo.getCreationDate());
        System.out.println("Keywords: " + docInfo.getKeywords());
        System.out.println("Modify Date: " + docInfo.getModDate());
        System.out.println("Subject: " + docInfo.getSubject());
        System.out.println("Title: " + docInfo.getTitle());
    }

Set PDF File Information

Aspose.PDF for Java allows you to set file-specific information for a PDF, information like author, creation date, subject, and title.

To set this information:

1. Create a DocumentInfo object.
2. Set the values of the properties.
3. Save the updated document using the Document class’ save() method.

Please note that you cannot set values against the Producer and Creator fields, because Aspose.PDF for Java x.x.x will be displayed against these fields.

The following code snippet shows you how to set PDF file information.

 public static void SetPDFFileInformation() {
        // Open document
        Document pdfDocument = new Document(_dataDir + "sample.pdf");

        // Specify document information
        DocumentInfo docInfo = new DocumentInfo(pdfDocument);

        docInfo.setAuthor("Aspose");
        docInfo.setCreationDate(new java.util.Date());
        docInfo.setKeywords("Aspose.Pdf, DOM, API");
        docInfo.setModDate(new java.util.Date());
        docInfo.setSubject("PDF Information");
        docInfo.setTitle("Setting PDF Document Information");

        // Save output document
        pdfDocument.save(_dataDir + "SetFileInfo_out.pdf");
    }

Get XMP Metadata from PDF File

Aspose.PDF for Java allows you to access a PDF file’s XMP metadata.

To get a PDF file’s metadata,

1. Create a Document object and open the input PDF file.
2. Use the getMetadata() property to get the metadata.

The following code snippet shows you how to get metadata from the PDF file.

   public static void GetXMPMetadata() {

        // Open document
        Document pdfDocument = new Document(_dataDir + "SetXMPMetadata.pdf");

        System.out.println("xmp:CreateDate: " + pdfDocument.getMetadata().get_Item("xmp:CreateDate"));
        System.out.println("xmp:Nickname: " + pdfDocument.getMetadata().get_Item("xmp:Nickname"));
        System.out.println("xmp:CustomProperty: " + pdfDocument.getMetadata().get_Item("xmp:CustomProperty"));

    }

Set XMP Metadata in a PDF File

Aspose.PDF for Java allows you to set metadata in a PDF file. To set metadata:

1. Create a Document object.
2. Set metadata values using the getMetadata() property.
3. Save the updated document using the save() method of the Document object.

The following code snippet shows you how to set metadata in a PDF file.

    public static void SetXMPMetadata() {

        // Open document
        Document pdfDocument = new Document(_dataDir + "sample.pdf");

        // Set properties
        pdfDocument.getMetadata().set_Item("xmp:CreateDate", new XmpValue(new java.util.Date()));
        pdfDocument.getMetadata().set_Item("xmp:Nickname", new XmpValue("Nickname"));
        pdfDocument.getMetadata().set_Item("xmp:CustomProperty", new XmpValue("Custom Value"));

        // Save document
        pdfDocument.save(_dataDir + "SetXMPMetadata.pdf");
    }

Insert Metadata with Prefix

Some developers need to create a new metadata namespace with a prefix. The following code snippet shows how to insert metadata with prefix.

    public static void InsertMetadataWithPrefix() {
        // Open document
        Document pdfDocument = new Document(_dataDir + "SetXMPMetadata.pdf");
        pdfDocument.getMetadata().registerNamespaceUri("adc", "http://tempuri.org/adc/1.0");
        pdfDocument.getMetadata().set_Item("adc:format", new XmpValue("application/pdf"));
        pdfDocument.getMetadata().set_Item("adc:title", new XmpValue("alternative title"));        
        // Save document
        pdfDocument.save(_dataDir + "SetPrefixMetadata_out.pdf");
    }
}