Working with ZIP archives Leave feedback

The API allows detecting ZIP archives and reading format metadata. The following steps are needed to be followed:

• Load a ZIP archive
• Get the root metadata package
• Extract  the native metadata package using the ZipRootPackage.getZipPackage method
• Read the ZIP archive properties
• Loop through ZipPackage.getFiles to extract information about the archived files 

The following code snippet shows how to get metadata from a ZIP archive.

advanced_usage.managing_metadata_for_specific_formats.archive.ZipReadNativeMetadataProperties

Charset charset = Charset.forName("cp866");

try (Metadata metadata = new Metadata(Constants.InputZip)) {
    ZipRootPackage root = metadata.getRootPackageGeneric();

    System.out.println(root.getZipPackage().getComment());
    System.out.println(root.getZipPackage().getTotalEntries());

    for (ZipFile file : root.getZipPackage().getFiles()) {
        System.out.println(file.getName());
        System.out.println(file.getCompressedSize());
        System.out.println(file.getCompressionMethod());
        System.out.println(file.getFlags());
        System.out.println(file.getModificationDateTime());
        System.out.println(file.getUncompressedSize());

        // Use a specific encoding for the file names
        System.out.println(new String(file.getRawName(), charset));
    }
}

GroupDocs.Metadata for Java allows you to update the user comment in a ZIP archive. The following steps are needed to be followed:

• Load a ZIP archive
• Get the root metadata package
• Update the comment using the ZipPackage.setComment method
• Save the changes

The following code snippet demonstrates the usage of this feature.

advanced_usage.managing_metadata_for_specific_formats.archive.ZipUpdateArchiveComment

try (Metadata metadata = new Metadata(Constants.InputZip)) {
	ZipRootPackage root = metadata.getRootPackageGeneric();

	root.getZipPackage().setComment("updated comment");

	metadata.save(Constants.OutputZip);
}

GroupDocs.Metadata for Java allows you to remove the user comment associated with a ZIP archive. The following code snippet demonstrates the usage of this feature.

advanced_usage.managing_metadata_for_specific_formats.archive.ZipRemoveArchiveComment

try (Metadata metadata = new Metadata(Constants.InputZip)) {
	ZipRootPackage root = metadata.getRootPackageGeneric();

	root.getZipPackage().setComment(null);

	metadata.save(Constants.OutputZip);
}

You may easily run the code above and see the feature in action in our GitHub examples:

• GroupDocs.Metadata for .NET examples

• GroupDocs.Metadata for Java examples

Along with full featured Java library we provide simple, but powerful free Apps.

You are welcome to view and edit metadata of PDF, DOC, DOCX, PPT, PPTX, XLS, XLSX, emails, images and more with our free online Free Online Document Metadata Viewing and Editing App.