需要从bytearray(Java)创建PDF

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDPageContentStream;
import org.apache.pdfbox.pdmodel.common.PDRectangle;
import org.apache.pdfbox.pdmodel.font.PDType1Font;

import java.io.ByteArrayOutputStream;
import java.io.IOException;

public class PDFFromByteArray {
    public static void main(String[] args) throws IOException {
        try (PDDocument document = new PDDocument()) {
            PDPage page = new PDPage(PDRectangle.A4);
            document.addPage(page);

            try (PDPageContentStream contentStream = new PDPageContentStream(document, page)) {
                contentStream.setFont(PDType1Font.HELVETICA_BOLD, 18);
                contentStream.beginText();
                contentStream.newLineAtOffset(100, 600);
                contentStream.showText("Hello World!");
                contentStream.endText();
            }

            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
            document.save(byteArrayOutputStream);
            byte[] pdfBytes = byteArrayOutputStream.toByteArray();
        }
    }
}

import com.itextpdf.kernel.pdf.PdfDocument;
import com.itextpdf.kernel.pdf.PdfWriter;
import com.itextpdf.layout.Document;
import com.itextpdf.layout.element.Paragraph;

import java.io.ByteArrayOutputStream;
import java.io.IOException;

public class PDFFromByteArray {
    public static void main(String[] args) throws IOException {
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        PdfWriter pdfWriter = new PdfWriter(byteArrayOutputStream);
        PdfDocument pdfDocument = new PdfDocument(pdfWriter);
        Document document = new Document(pdfDocument);

        document.add(new Paragraph("Hello World!"));

        document.close();
        byte[] pdfBytes = byteArrayOutputStream.toByteArray();
    }
}