前不久公司需要为用户生成一份报告，报告的模板是统一的，内容不同，并且用户可以打印。于是调研了有关 PDF 生成的方式，这里简单记录一下。方案是使用 itextpdf 这个类库对 PDF 模板进行内容填充，从而达到效果。demo 代码中有用到 zxing 进行二维码的生成，多张 PDF 合并成一张 PDF 等。

官方 tutorial

Examples iText 7 jump-start tutorial

注意点

准备 PDF From 域需要 AdobeAcrobat DC 中的高级功能，普通版无法添加 From 域。

部分代码

下面的代码实现了 PDF 填充，多张 PDF 合并成一个 PDF，PDF 中添加图片，根据 URL 生成二维码图片。
PDF 模板下载地址：模板

package pdf;

import com.alibaba.druid.util.StringUtils;
import com.itextpdf.forms.PdfAcroForm;
import com.itextpdf.forms.fields.PdfFormField;
import com.itextpdf.io.image.ImageDataFactory;
import com.itextpdf.io.source.ByteArrayOutputStream;
import com.itextpdf.kernel.font.PdfFont;
import com.itextpdf.kernel.font.PdfFontFactory;
import com.itextpdf.kernel.pdf.PdfDocument;
import com.itextpdf.kernel.pdf.PdfReader;
import com.itextpdf.kernel.pdf.PdfWriter;
import com.itextpdf.kernel.utils.PdfMerger;
import com.itextpdf.layout.Document;
import com.itextpdf.layout.element.Image;
import com.itextpdf.layout.element.Paragraph;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * 填充 pdf 并插入 二维码，如果有多个 pdf 进行合并操作
 *
 * @author Chengloong
 */
public class PdfTempleTest {

    private static final int NORMAL_FONT_SIZE = 12;
    private static final int TWO_ROWS_FONT_SIZE = 7;

    public static void main(String[] args) throws Exception {

        //生成二维码
        QRCodeUtil.generateQRCode("https://blog.csdn.net/jinqilin721/article/details/78841028", 600, 600, "jpg", "D:\\qr2.png");

        //填充 pdf 模板
        fillTemplate();

    }

    /**
     * 利用模板生成pdf
     */
    public static void fillTemplate() {
        // 模板路径
        String templatePath = "D:/pdf-template-form.pdf";

        List<ByteArrayOutputStream> baosList = new ArrayList<>();
        try {

            //根据路径生成 pdf
//          PdfWriter writer = new PdfWriter(newPDFPath);

            //内存中创建 PDF
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            PdfWriter writer = new PdfWriter(baos);
            PdfReader reader = new PdfReader(templatePath);
            PdfDocument pdf = new PdfDocument(reader, writer);
            PdfAcroForm form = PdfAcroForm.getAcroForm(pdf, true);
            Map<String, PdfFormField> fields = form.getFormFields();

            //处理中文问题
            PdfFont font = PdfFontFactory.createFont("STSongStd-Light", "UniGB-UCS2-H", false);

            for (String name : fields.keySet()) {
                //获取文本域名称
                if (StringUtils.equals(name, "name")) {
                    fields.get(name).setValue("李四").setFont(font).setFontSize(NORMAL_FONT_SIZE);
                }

                if (StringUtils.equals(name, "sex")) {
                    fields.get(name).setValue("男").setFont(font).setFontSize(NORMAL_FONT_SIZE);
                }

                if (StringUtils.equals(name, "id_number")) {
                    fields.get(name).setValue("320123199309223211").setFont(font).setFontSize(NORMAL_FONT_SIZE);
                }

                if (StringUtils.equals(name, "address")) {
                    fields.get(name).setValue("江苏省无锡市滨湖区第一人民医院").setFont(font).setFontSize(NORMAL_FONT_SIZE);
                }

                if (StringUtils.equals(name, "input_1")) {
                    //超过一行的文字使用 7 号字体
                    fields.get(name).setValue("盐城继续教育公需课我是一段很长很长很长超过一行的文字").setFont(font).setFontSize(TWO_ROWS_FONT_SIZE);
                }

                if (StringUtils.equals(name, "input_2")) {
                    fields.get(name).setValue("专业类别").setFont(font).setFontSize(NORMAL_FONT_SIZE);
                }

                if (StringUtils.equals(name, "input_3")) {
                    fields.get(name).setValue("学习形式").setFont(font).setFontSize(NORMAL_FONT_SIZE);
                }

                if (StringUtils.equals(name, "input_4")) {
                    fields.get(name).setValue("2").setFont(font).setFontSize(NORMAL_FONT_SIZE);
                }

                if (StringUtils.equals(name, "input_5")) {
                    fields.get(name).setValue("20180909").setFont(font).setFontSize(NORMAL_FONT_SIZE);
                }

                if (StringUtils.equals(name, "input_6")) {
                    fields.get(name).setValue("优秀").setFont(font).setFontSize(NORMAL_FONT_SIZE);
                }
            }

            //生成的 pdf 不可以编辑
            form.flattenFields();

            //插入图片
            Document document = new Document(pdf);
            Image image = new Image(ImageDataFactory.create("D:\\qr2.png"));
            image.setWidth(80);
            image.setHeight(80);

            Paragraph paragraph = new Paragraph().add(image);
            paragraph.setPaddings(140, 0, 0, 550);

            document.add(paragraph);
            document.close();
            pdf.close();

            baosList.add(baos);


            mergerPDF(baosList);

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 合并 PDF
     */
    public static void mergerPDF(List<ByteArrayOutputStream> baosList) {
        try {
            PdfWriter writer = new PdfWriter("D:\\merger.pdf");
            PdfDocument pdf = new PdfDocument(writer);

            PdfMerger merger = new PdfMerger(pdf);

//          这里可以直接读取已存在的文件
//          PdfMerger merger = new PdfMerger(pdf);
//          PdfDocument firstSourcePdf = new PdfDocument(new PdfReader("D:\\photo1.pdf"));
//          merger.merge(firstSourcePdf, 1, firstSourcePdf.getNumberOfPages());

            for (ByteArrayOutputStream byteArrayOutputStream : baosList) {
                PdfDocument firstSourcePdf = new PdfDocument(new PdfReader(new ByteArrayInputStream(byteArrayOutputStream.toByteArray())));
                merger.merge(firstSourcePdf, 1, firstSourcePdf.getNumberOfPages());
            }

            pdf.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

package pdf;

import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Map;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletResponse;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.Binarizer;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.DecodeHintType;
import com.google.zxing.EncodeHintType;
import com.google.zxing.LuminanceSource;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.Result;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

/**
 * 二维码生成工具类
 */
public final class QRCodeUtil extends LuminanceSource {

    private static final Logger logger = LoggerFactory.getLogger(QRCodeUtil.class);

    // 二维码颜色
    private static final int BLACK = 0xFF000000;
    // 二维码颜色
    private static final int WHITE = 0xFFFFFFFF;

    private final BufferedImage image;
    private final int left;
    private final int top;

    public QRCodeUtil(BufferedImage image) {
        this(image, 0, 0, image.getWidth(), image.getHeight());
    }

    public QRCodeUtil(BufferedImage image, int left, int top, int width, int height) {
        super(width, height);
        int sourceWidth = image.getWidth();
        int sourceHeight = image.getHeight();
        if (left + width > sourceWidth || top + height > sourceHeight) {
            throw new IllegalArgumentException("Crop rectangle does not fit within image data.");
        }
        for (int y = top; y < top + height; y++) {
            for (int x = left; x < left + width; x++) {
                if ((image.getRGB(x, y) & 0xFF000000) == 0) {
                    image.setRGB(x, y, 0xFFFFFFFF); // = white
                }
            }
        }
        this.image = new BufferedImage(sourceWidth, sourceHeight, BufferedImage.TYPE_BYTE_GRAY);
        this.image.getGraphics().drawImage(image, 0, 0, null);
        this.left = left;
        this.top = top;
    }

    @Override
    public byte[] getRow(int y, byte[] row) {
        if (y < 0 || y >= getHeight()) {
            throw new IllegalArgumentException("Requested row is outside the image: " + y);
        }
        int width = getWidth();
        if (row == null || row.length < width) {
            row = new byte[width];
        }
        image.getRaster().getDataElements(left, top + y, width, 1, row);
        return row;
    }

    @Override
    public byte[] getMatrix() {
        int width = getWidth();
        int height = getHeight();
        int area = width * height;
        byte[] matrix = new byte[area];
        image.getRaster().getDataElements(left, top, width, height, matrix);
        return matrix;
    }

    @Override
    public boolean isCropSupported() {
        return true;
    }

    @Override
    public LuminanceSource crop(int left, int top, int width, int height) {
        return new QRCodeUtil(image, this.left + left, this.top + top, width, height);
    }

    @Override
    public boolean isRotateSupported() {
        return true;
    }

    @Override
    public LuminanceSource rotateCounterClockwise() {
        int sourceWidth = image.getWidth();
        int sourceHeight = image.getHeight();
        AffineTransform transform = new AffineTransform(0.0, -1.0, 1.0, 0.0, 0.0, sourceWidth);
        BufferedImage rotatedImage = new BufferedImage(sourceHeight, sourceWidth, BufferedImage.TYPE_BYTE_GRAY);
        Graphics2D g = rotatedImage.createGraphics();
        g.drawImage(image, transform, null);
        g.dispose();
        int width = getWidth();
        return new QRCodeUtil(rotatedImage, top, sourceWidth - (left + width), getHeight(), width);
    }

    /**
     * @param matrix
     * @return
     */
    private static BufferedImage toBufferedImage(BitMatrix matrix) {
        int width = matrix.getWidth();
        int height = matrix.getHeight();
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        for (int x = 0; x < width; x++) {
            for (int y = 0; y < height; y++) {
                image.setRGB(x, y, matrix.get(x, y) ? BLACK : WHITE);
            }
        }
        return image;
    }

    /**
     * 生成二维码图片
     *
     * @param matrix
     * @param format
     * @param file
     * @throws IOException
     */
    public static void writeToFile(BitMatrix matrix, String format, File file) throws IOException {
        BufferedImage image = toBufferedImage(matrix);
        if (!ImageIO.write(image, format, file)) {
            throw new IOException("Could not write an image of format " + format + " to " + file);
        }
    }

    /**
     * 生成二维码图片流
     *
     * @param matrix
     * @param format
     * @param stream
     * @throws IOException
     */
    public static void writeToStream(BitMatrix matrix, String format, OutputStream stream) throws IOException {
        BufferedImage image = toBufferedImage(matrix);
        if (!ImageIO.write(image, format, stream)) {
            throw new IOException("Could not write an image of format " + format);
        }
    }

    /**
     * 根据内容，生成指定宽高、指定格式的二维码图片
     *
     * @param text   内容
     * @param width  宽
     * @param height 高
     * @param format 图片格式
     * @return 生成的二维码图片路径
     * @throws Exception
     */
    public static String generateQRCode(String text, int width, int height, String format, String pathName)
            throws Exception {
        Hashtable<EncodeHintType, Object> hints = new Hashtable<>();
        hints.put(EncodeHintType.CHARACTER_SET, "utf-8");// 指定编码格式
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);// 指定纠错等级
        hints.put(EncodeHintType.MARGIN, 0); // 白边大小，取值范围0~4
        BitMatrix bitMatrix = new MultiFormatWriter().encode(text, BarcodeFormat.QR_CODE, width, height, hints);
        File outputFile = new File(pathName);
        writeToFile(bitMatrix, format, outputFile);
        return pathName;
    }

    /**
     * 输出二维码图片流
     *
     * @param text     二维码内容
     * @param width    二维码宽
     * @param height   二维码高
     * @param format   图片格式eg: png, jpg, gif
     * @param response HttpServletResponse
     * @throws Exception
     */
    public static void generateQRCode(String text, int width, int height, String format, HttpServletResponse response)
            throws Exception {
        Hashtable<EncodeHintType, Object> hints = new Hashtable<>();
        hints.put(EncodeHintType.CHARACTER_SET, "utf-8");// 指定编码格式
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);// 指定纠错等级
        hints.put(EncodeHintType.MARGIN, 1); // 白边大小，取值范围0~4
        BitMatrix bitMatrix = new MultiFormatWriter().encode(text, BarcodeFormat.QR_CODE, width, height, hints);
        writeToStream(bitMatrix, format, response.getOutputStream());
    }

    /**
     * 解析指定路径下的二维码图片
     *
     * @param filePath 二维码图片路径
     * @return
     */
    public static String parseQRCode(String filePath) {
        String content = "";
        try {
            File file = new File(filePath);
            BufferedImage image = ImageIO.read(file);
            LuminanceSource source = new QRCodeUtil(image);
            Binarizer binarizer = new HybridBinarizer(source);
            BinaryBitmap binaryBitmap = new BinaryBitmap(binarizer);
            Map<DecodeHintType, Object> hints = new HashMap<>();
            hints.put(DecodeHintType.CHARACTER_SET, "UTF-8");
            MultiFormatReader formatReader = new MultiFormatReader();
            Result result = formatReader.decode(binaryBitmap, hints);

            logger.info("result 为：" + result.toString());
            logger.info("resultFormat 为：" + result.getBarcodeFormat());
            logger.info("resultText 为：" + result.getText());
            // 设置返回值
            content = result.getText();
        } catch (Exception e) {
            logger.error(e.getMessage());
        }
        return content;
    }

    public static void main(String[] args) {
        String text = "hello world!"; // 随机生成验证码
        System.out.println("随机码： " + text);
        int width = 100; // 二维码图片的宽
        int height = 100; // 二维码图片的高
        String format = "png"; // 二维码图片的格式

        try {
            // 生成二维码图片，并返回图片路径
            String pathName = generateQRCode(text, width, height, format, "D:/new.png");
            System.out.println("生成二维码的图片路径： " + pathName);

            String content = parseQRCode(pathName);
            System.out.println("解析出二维码的图片的内容为： " + content);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}