基于Itextpdf合成PDF

原创：转载需注明原创地址 https://www.cnblogs.com/fanerwei222/p/12023314.html

开发过程中有用到PDF合成, 记录一下合成的方法和代码.

使用工具 : itextpdf

<!-- https://mvnrepository.com/artifact/com.itextpdf/itextpdf -->
<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>itextpdf</artifactId>
    <version>5.5.13</version>
</dependency>

合成工具类:

import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.pdf.PdfCopy;
import com.itextpdf.text.pdf.PdfImportedPage;
import com.itextpdf.text.pdf.PdfReader;
import org.apache.tomcat.util.http.fileupload.IOUtils;
import org.springframework.util.Assert;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.List;

/**
 * TODO
 * 合并PDF流工具类
 */
public class MergePdfUtils {

    /**
     * 根据字节数组合并PDF
     * @param pdfBytes pdf字节流数组
     * @param len 字节流数组总长度
     * @throws IOException
     * @throws DocumentException
     */
    public static byte[] mergePdfBytes(List<byte[]> pdfBytes, int len) throws IOException, DocumentException {
        Assert.notEmpty(pdfBytes, "参数不能为空!");
        byte[] newPdfByte = new byte[len];
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        try {
            Document document = new Document(new PdfReader(pdfBytes.get(0)).getPageSize(1));
            PdfCopy copy = new PdfCopy(document, outputStream);
            document.open();
            PdfReader reader = null;
            for (int i = 0; i < pdfBytes.size(); i++) {
                reader = new PdfReader(pdfBytes.get(i));
                int n = reader.getNumberOfPages();
                for (int j = 1; j <= n; j++) {
                    document.newPage();
                    PdfImportedPage page = copy.getImportedPage(reader, j);
                    copy.addPage(page);
                }
            }
            document.close();
            newPdfByte = outputStream.toByteArray();
        } catch (IOException | DocumentException e) {
            e.printStackTrace();
        } finally {
            IOUtils.closeQuietly(outputStream);
        }
        return newPdfByte;
    }
}

还有一个合成为文件的工具类:

import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.pdf.PdfCopy;
import com.itextpdf.text.pdf.PdfImportedPage;
import com.itextpdf.text.pdf.PdfReader;

import java.io.FileOutputStream;
import java.io.IOException;
import java.util.List;

/**
 * TODO
 * 合并PDF为文件
 */
public class MergePdfFile {
    /**
     * 合成为文件
     * @param files 文件所在的路径列表
     * @param newfile 新文件的路径
     * @throws IOException
     * @throws DocumentException
     */
    public static void mergePdfFiles(List<String> files, String newfile) throws IOException, DocumentException {
        Document document = new Document(new PdfReader(files.get(0)).getPageSize(1));
        PdfCopy copy = new PdfCopy(document, new FileOutputStream(newfile));
        document.open();
        for (int i = 0; i < files.size(); i++) {
            PdfReader reader = new PdfReader(files.get(i));
            int n = reader.getNumberOfPages();
            for (int j = 1; j <= n; j++) {
                document.newPage();
                PdfImportedPage page = copy.getImportedPage(reader, j);
                copy.addPage(page);
            }
        }
        document.close();
    }
}