Java

Unzip a ZIP Entry Directly into a BinData Object Using ZipEntry.UnzipToBd

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This example demonstrates how to use the ZipEntry.UnzipToBd method to inflate a ZIP entry directly into a BinData object.

The entry contents are uncompressed entirely in memory without creating a file on disk.

This is useful when:

• Processing ZIP entry data entirely in memory
• Avoiding temporary filesystem files
• Working with binary files such as images, PDFs, or certificates
• Passing uncompressed ZIP data directly to other APIs

The example opens a ZIP archive, locates a PDF entry, inflates it into a BinData object, and then writes the uncompressed bytes to a new file.

Suppose the ZIP archive contains:

docs/report.pdf

The entry is uncompressed directly into memory before optionally being saved to:

qa_output/report.pdf

Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    boolean success = false;

    CkZip zip = new CkZip();

    // Open an existing ZIP archive.
    success = zip.OpenZip("qa_data/zips/documents.zip");
    if (success == false) {
        System.out.println(zip.lastErrorText());
        return;
        }

    // Locate the PDF entry within the ZIP archive.
    CkZipEntry entry = new CkZipEntry();

    success = zip.EntryOf("docs/report.pdf",entry);
    if (success == false) {
        System.out.println("ZIP entry not found.");
        zip.CloseZip();
        return;
        }

    // ------------------------------------------------------------
    // Inflate the ZIP entry directly into a BinData object.
    // 
    // The uncompressed bytes are stored entirely in memory.
    // 
    CkBinData pdfData = new CkBinData();

    success = entry.UnzipToBd(pdfData);
    if (success == false) {
        System.out.println(entry.lastErrorText());
        return;
        }

    System.out.println("Uncompressed size = " + pdfData.get_NumBytes());
    System.out.println("");

    // ------------------------------------------------------------
    // Optionally save the uncompressed bytes to a file.
    // 
    success = pdfData.WriteFile("qa_output/report.pdf");
    if (success == false) {
        System.out.println(pdfData.lastErrorText());
        return;
        }

    zip.CloseZip();

    System.out.println("PDF extracted successfully.");
  }
}