ZipMultiplePdf

import com.itextpdf.html2pdf.ConverterProperties;
import com.itextpdf.html2pdf.HtmlConverter;
import com.itextpdf.kernel.pdf.PdfDocument;
import com.itextpdf.kernel.pdf.PdfWriter;
import com.itextpdf.layout.Document;
import net.lingala.zip4j.ZipFile;
import net.lingala.zip4j.model.ZipParameters;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;


public class ZipMultiplePdf {

    private static final String PATH = "D:\\IDEA\\test\\src\\main\\resources\\";
    private static final String[] FILES = { "test1.html", "test2.html", "test3.html" };

    public static void main(String[] args) throws Exception {
        ZipFile zipFile = new ZipFile("data.zip");
        for (String file : FILES) {
            ByteArrayOutputStream bao = new ByteArrayOutputStream();
            PdfWriter writer = new PdfWriter(bao);
            PdfDocument pdf = new PdfDocument(writer);
            ConverterProperties props = new ConverterProperties();
            Document document = HtmlConverter.convertToDocument(new FileInputStream(PATH + file), pdf, props);
            document.close();
            ZipParameters parameters = new ZipParameters();
            parameters.setFileNameInZip(file.substring(0, file.lastIndexOf(".")) + ".pdf");
            zipFile.addStream(new ByteArrayInputStream(bao.toByteArray()), parameters);
        }
    }

}