Java

Compress a File to Gzip with Custom Metadata

See more Gzip Examples

This example demonstrates how to use the CompressFile method to create a Gzip (.gz) file while customizing the metadata embedded in the Gzip header.

Before compression, several properties are set:

• Comment: Adds a descriptive comment to the Gzip file.
• Filename: Specifies the filename to embed in the Gzip data, which may be used by extraction tools as the default output name.
• CompressionLevel: Controls the tradeoff between compression ratio and speed (set to maximum in this example).
• LastModStr: Sets the last-modified timestamp using an RFC 822 formatted date string.

After setting these properties, the input file is compressed and written to a .gz file. This approach allows you to embed meaningful metadata along with the compressed data.

Chilkat2 Java

import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Gzip;

public class ChilkatExample {

    public static void main(String[] args) {
        // This example demonstrates how to compress a file to Gzip format
        // while setting custom metadata such as comment, filename,
        // compression level, and last-modified date.

        Gzip gzip = new Gzip();

        // Set custom Gzip properties:
        gzip.setComment("Example Gzip file created with Chilkat");
        gzip.setFilename("custom_name.txt");
        gzip.setCompressionLevel(9);
        gzip.setLastModStr("Wed, 1 Apr 2025 12:45:26 -0500");

        // The file to be compressed:
        String inputFile = "example.txt";
        String outputFile = "example.txt.gz";

        // Compress the file:
        try {
            gzip.compressFile(inputFile, outputFile);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("Compression successful.");
        System.out.println("Gzip file created: " + outputFile);
    }
}