(Java) Unzip a Text File Entry into a StringBuilder Using ZipEntry.UnzipToSb

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This example demonstrates how to use the ZipEntry.UnzipToSb method to inflate a text file entry directly into a StringBuilder object.

The ZIP entry is uncompressed entirely in memory and appended to the StringBuilder without creating a temporary file on disk.

This is useful when:

• Processing text files directly in memory
• Avoiding temporary filesystem files
• Reading configuration files, JSON, XML, CSV, or source code from ZIP archives
• Automatically converting line endings while inflating the text

The srcCharset argument specifies how the uncompressed bytes should be interpreted, such as:

• utf-8
• utf-16
• windows-1252

The lineEndingBehavior argument controls line-ending conversion:

• 0 — Leave line endings unchanged
• 1 — Convert all line endings to bare LF
• 2 — Convert all line endings to CRLF

Suppose the ZIP archive contains:

config/settings.json

The example inflates the JSON file directly into a StringBuilder.

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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/configFiles.zip");
    if (success == false) {
        System.out.println(zip.lastErrorText());
        return;
        }

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

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

    // ------------------------------------------------------------
    // Inflate the ZIP entry directly into a StringBuilder.
    // 
    // The uncompressed text is appended to the StringBuilder.
    // 
    CkStringBuilder sb = new CkStringBuilder();

    // Leave line endings unchanged.
    int lineEndingBehavior = 0;

    // Interpret the uncompressed bytes as UTF-8 text.
    String srcCharset = "utf-8";

    success = entry.UnzipToSb(lineEndingBehavior,srcCharset,sb);
    if (success == false) {
        System.out.println(entry.lastErrorText());
        return;
        }

    System.out.println("Uncompressed text:");
    System.out.println("");
    System.out.println(sb.getAsString());

    zip.CloseZip();

    System.out.println("Done.");
  }
}