A rendered report can be exported to any supported format straight from Java code, using StiExportManager.

Render, then export to a stream.
StiReport report = StiSerializeManager.deserializeReport(new File(reportPath));
report.render();

try (FileOutputStream out = new FileOutputStream("report.pdf")) {
    StiExportManager.exportPdf(report, out);
    // StiExportManager.exportExcel(report, out);
    // StiExportManager.exportWord(report, out);
    // StiExportManager.exportHtml(report, out);
}

How it works. Each StiExportManager method serializes the rendered report to one format, so the same document can be saved as PDF, Office or image files.
На скриншоте ниже Вы можете увидеть результат выполнения данного кода:

Exporting a Report from Code