1.pdfbox对pdf流操作

//这个是获取到的pdf的base64
        BASE64Decoder base64Decoder = new BASE64Decoder();
        //base64转成的数组
        byte[] pdfData = base64Decoder.decodeBuffer(pdfBase64);
        //通过pdfbox对pdf流新增空白页
        PDDocument document = PDDocument.load(pdfData);
        document.addPage(new PDPage());
        ByteArrayOutputStream bos=new ByteArrayOutputStream();
        document.save(bos);
        byte[] pdfDataAddPage = bos.toByteArray();
        document.close();

2.pdfbox小demo

public static void main(String[] args) throws IOException { 
		//通过pdfbox对pdf流新增空白页
		File file = new File("Z:\\workSpace\\csdc\\csdc-h5\\src\\main\\resources\\file\\pdfCaSign.pdf");
		PDDocument document = PDDocument.load(file);
		//新增空白页
		PDPage blankPage = new PDPage();
		//获取空白页在文档中的内容流
		PDPageContentStream contentStream = new PDPageContentStream(document, blankPage);
		//设置文本字体格式和大小
		File fontFile = new File("C:\\Windows\\Fonts\\simfang.ttf");
		PDType0Font font = PDType0Font.load(document, fontFile);

		setText(contentStream,font);

		//将空白页拼接至pdf尾页
		document.addPage(blankPage);
		ByteArrayOutputStream bos=new ByteArrayOutputStream();
		document.save(bos);
		byte[] pdfDataAddPage = bos.toByteArray();
		document.close();
		PDDocument newDoc = PDDocument.load(pdfDataAddPage);
		newDoc.save("Z:\\newDoc.pdf");
	}

	public static void setText(PDPageContentStream contentStream,PDType0Font font) throws IOException { 
        //开启文本输入流
		contentStream.beginText();
		contentStream.setFont(font, 12);
		//设置文本页面定位
		contentStream.newLineAtOffset(20, 200);
		//将文本写入文本流
		contentStream.showText("This is a test text ! 用于测试页面是否乱码。");
		contentStream.newLine();
		contentStream.newLineAtOffset(40,220);
		contentStream.showText("投保人签字：______________");
		contentStream.newLine();
		contentStream.newLineAtOffset(60,230);
		contentStream.showText("被保人签字：______________");
		contentStream.newLine();
		contentStream.newLineAtOffset(60,235);
		contentStream.showText("受益人签字：______________");
		//结束文本输入流
		contentStream.endText();
		//关闭流
		contentStream.close();
	}