I don't agree to the others and have a POC for your question: You can extract the XMP Metadata of images using pdfbox in the following way:
public void getXMPInformation() {
// Open PDF document
PDDocument document = null;
try {
document = PDDocument.load(PATH_TO_YOUR_DOCUMENT);
} catch (IOException e) {
e.printStackTrace();
}
// Get all pages and loop through them
List pages = document.getDocumentCatalog().getAllPages();
Iterator iter = pages.iterator();
while( iter.hasNext() ) {
PDPage page = (PDPage)iter.next();
PDResources resources = page.getResources();
Map images = null;
// Get all Images on page
try {
images = resources.getImages();
} catch (IOException e) {
e.printStackTrace();
}
if( images != null ) {
// Check all images for metadata
Iterator imageIter = images.keySet().iterator();
while( imageIter.hasNext() ) {
String key = (String)imageIter.next();
PDXObjectImage image = (PDXObjectImage)images.get( key );
PDMetadata metadata = image.getMetadata();
System.out.println("Found a image: Analyzing for Metadata");
if (metadata == null) {
System.out.println("No Metadata found for this image.");
} else {
InputStream xmlInputStream = null;
try {
xmlInputStream = metadata.createInputStream();
} catch (IOException e) {
e.printStackTrace();
}
try {
System.out.println("--------------------------------------------------------------------------------");
String mystring = convertStreamToString(xmlInputStream);
System.out.println(mystring);
} catch (IOException e) {
e.printStackTrace();
}
}
// Export the images
String name = getUniqueFileName( key, image.getSuffix() );
System.out.println( "Writing image:" + name );
try {
image.write2file( name );
} catch (IOException e) {
// TODO Auto-generated catch block
//e.printStackTrace();
}
System.out.println("--------------------------------------------------------------------------------");
}
}
}
}
And the "Helper methods":
public String convertStreamToString(InputStream is) throws IOException {
/*
* To convert the InputStream to String we use the BufferedReader.readLine()
* method. We iterate until the BufferedReader return null which means
* there's no more data to read. Each line will appended to a StringBuilder
* and returned as String.
*/
if (is != null) {
StringBuilder sb = new StringBuilder();
String line;
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(is, "UTF-8"));
while ((line = reader.readLine()) != null) {
sb.append(line).append("\n");
}
} finally {
is.close();
}
return sb.toString();
} else {
return "";
}
}
private String getUniqueFileName( String prefix, String suffix ) {
/*
* imagecounter is a global variable that counts from 0 to the number of
* extracted images
*/
String uniqueName = null;
File f = null;
while( f == null || f.exists() ) {
uniqueName = prefix + "-" + imageCounter;
f = new File( uniqueName + "." + suffix );
}
imageCounter++;
return uniqueName;
}
Note: This is a quick and dirty proof of concept and not a well-styled code.
The Images must have XMP-Metadata when placed in InDesign before building the PDF document. The XMP-Metdadata can be set by using Photoshop for example. Please be aware, that p.e. not all IPTC/Exif/... Information is converted into the XMP-Metadata. Only a small number of fields are converted.
I'm using this method on JPG and PNG images, placed in PDFs build with InDesign. It works well and I can get all image-informations after the production-steps from the ready PDFs (picture coating).
