[英]How to merge two PDF files into one in Java?
我想使用PDFBox將許多 PDF 文件合並為一個文件,這就是我所做的:
PDDocument document = new PDDocument();
for (String pdfFile: pdfFiles) {
PDDocument part = PDDocument.load(pdfFile);
List<PDPage> list = part.getDocumentCatalog().getAllPages();
for (PDPage page: list) {
document.addPage(page);
}
part.close();
}
document.save("merged.pdf");
document.close();
其中pdfFiles
是一個ArrayList<String>
包含所有 PDF 文件。
當我運行上述內容時,我總是得到:
org.apache.pdfbox.exceptions.COSVisitorException: Bad file descriptor
難道我做錯了什么? 還有其他方法嗎?
為什么不使用 pdfbox 的PDFMergerUtility ?
PDFMergerUtility ut = new PDFMergerUtility();
ut.addSource(...);
ut.addSource(...);
ut.addSource(...);
ut.setDestinationFileName(...);
ut.mergeDocuments();
一個快速的谷歌搜索返回了這個錯誤: “保存帶有導入 PDF 的文檔時文件描述符錯誤” 。
看起來您需要將要合並的 PDF 保持打開狀態,直到您保存並關閉合並的 PDF。
這是一個即用型代碼,將四個 pdf 文件與來自http://central.maven.org/maven2/com/itextpdf/itextpdf/5.5.0/itextpdf-5.5.0.jar的 itext.jar 合並,更多關於http //tutorialspointexamples.com/
import com.itextpdf.text.Document;
import com.itextpdf.text.pdf.PdfContentByte;
import com.itextpdf.text.pdf.PdfImportedPage;
import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.PdfWriter;
/**
* This class is used to merge two or more
* existing pdf file using iText jar.
*/
public class PDFMerger {
static void mergePdfFiles(List<InputStream> inputPdfList,
OutputStream outputStream) throws Exception{
//Create document and pdfReader objects.
Document document = new Document();
List<PdfReader> readers =
new ArrayList<PdfReader>();
int totalPages = 0;
//Create pdf Iterator object using inputPdfList.
Iterator<InputStream> pdfIterator =
inputPdfList.iterator();
// Create reader list for the input pdf files.
while (pdfIterator.hasNext()) {
InputStream pdf = pdfIterator.next();
PdfReader pdfReader = new PdfReader(pdf);
readers.add(pdfReader);
totalPages = totalPages + pdfReader.getNumberOfPages();
}
// Create writer for the outputStream
PdfWriter writer = PdfWriter.getInstance(document, outputStream);
//Open document.
document.open();
//Contain the pdf data.
PdfContentByte pageContentByte = writer.getDirectContent();
PdfImportedPage pdfImportedPage;
int currentPdfReaderPage = 1;
Iterator<PdfReader> iteratorPDFReader = readers.iterator();
// Iterate and process the reader list.
while (iteratorPDFReader.hasNext()) {
PdfReader pdfReader = iteratorPDFReader.next();
//Create page and add content.
while (currentPdfReaderPage <= pdfReader.getNumberOfPages()) {
document.newPage();
pdfImportedPage = writer.getImportedPage(
pdfReader,currentPdfReaderPage);
pageContentByte.addTemplate(pdfImportedPage, 0, 0);
currentPdfReaderPage++;
}
currentPdfReaderPage = 1;
}
//Close document and outputStream.
outputStream.flush();
document.close();
outputStream.close();
System.out.println("Pdf files merged successfully.");
}
public static void main(String args[]){
try {
//Prepare input pdf file list as list of input stream.
List<InputStream> inputPdfList = new ArrayList<InputStream>();
inputPdfList.add(new FileInputStream("..\\pdf\\pdf_1.pdf"));
inputPdfList.add(new FileInputStream("..\\pdf\\pdf_2.pdf"));
inputPdfList.add(new FileInputStream("..\\pdf\\pdf_3.pdf"));
inputPdfList.add(new FileInputStream("..\\pdf\\pdf_4.pdf"));
//Prepare output stream for merged pdf file.
OutputStream outputStream =
new FileOutputStream("..\\pdf\\MergeFile_1234.pdf");
//call method to merge pdf files.
mergePdfFiles(inputPdfList, outputStream);
} catch (Exception e) {
e.printStackTrace();
}
}
}
使用org.apache.pdfbox的多個 pdf 合並方法:
public void mergePDFFiles(List<File> files,
String mergedFileName) {
try {
PDFMergerUtility pdfmerger = new PDFMergerUtility();
for (File file : files) {
PDDocument document = PDDocument.load(file);
pdfmerger.setDestinationFileName(mergedFileName);
pdfmerger.addSource(file);
pdfmerger.mergeDocuments(MemoryUsageSetting.setupTempFileOnly());
document.close();
}
} catch (IOException e) {
logger.error("Error to merge files. Error: " + e.getMessage());
}
}
在主程序中,使用文件列表和目標文件名調用mergePDFFiles方法。
String mergedFileName = "Merged.pdf";
mergePDFFiles(files, mergedFileName);
調用mergePDFFiles后,加載合並文件
File mergedFile = new File(mergedFileName);
package article14;
import java.io.File;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.util.PDFMergerUtility;
public class Pdf
{
public static void main(String args[])
{
new Pdf().createNew();
new Pdf().combine();
}
public void combine()
{
try
{
PDFMergerUtility mergePdf = new PDFMergerUtility();
String folder ="pdf";
File _folder = new File(folder);
File[] filesInFolder;
filesInFolder = _folder.listFiles();
for (File string : filesInFolder)
{
mergePdf.addSource(string);
}
mergePdf.setDestinationFileName("Combined.pdf");
mergePdf.mergeDocuments();
}
catch(Exception e)
{
}
}
public void createNew()
{
PDDocument document = null;
try
{
String filename="test.pdf";
document=new PDDocument();
PDPage blankPage = new PDPage();
document.addPage( blankPage );
document.save( filename );
}
catch(Exception e)
{
}
}
}
如果您想合並兩個文件,其中一個文件覆蓋另一個文件(例如:文檔 A 是一個模板,而文檔 B 有您要放在模板上的文本),這可以工作:
創建“doc”后,您想在其上編寫模板(templateFile) -
PDDocument watermarkDoc = PDDocument.load(getServletContext()
.getRealPath(templateFile));
Overlay overlay = new Overlay();
overlay.overlay(watermarkDoc, doc);
使用 iText(以字節為單位的現有 PDF)
public static byte[] mergePDF(List<byte[]> pdfFilesAsByteArray) throws DocumentException, IOException {
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
Document document = null;
PdfCopy writer = null;
for (byte[] pdfByteArray : pdfFilesAsByteArray) {
try {
PdfReader reader = new PdfReader(pdfByteArray);
int numberOfPages = reader.getNumberOfPages();
if (document == null) {
document = new Document(reader.getPageSizeWithRotation(1));
writer = new PdfCopy(document, outStream); // new
document.open();
}
PdfImportedPage page;
for (int i = 0; i < numberOfPages;) {
++i;
page = writer.getImportedPage(reader, i);
writer.addPage(page);
}
}
catch (Exception e) {
e.printStackTrace();
}
}
document.close();
outStream.close();
return outStream.toByteArray();
}
//假設我們要將一個 pdf 與另一個主 pdf 合並
InputStream is1 = null;
if (file1 != null) {
FileInputStream fis1 = new FileInputStream(file1);
byte[] file1Data = new byte[(int) file1.length()];
fis1.read(file1Data);
is1 = new java.io.ByteArrayInputStream(file1Data);
}
//
InputStream mainContent = <ur main content>
org.apache.pdfbox.pdmodel.PDDocument mergedPDF = new org.apache.pdfbox.pdmodel.PDDocument();
org.apache.pdfbox.pdmodel.PDDocument mainDoc = org.apache.pdfbox.pdmodel.PDDocument.load(mainContent);
org.apache.pdfbox.multipdf.PDFMergerUtility merger = new org.apache.pdfbox.multipdf.PDFMergerUtility();
merger.appendDocument(mergedPDF, mainDoc);
PDDocument doc1 = null;
if (is1 != null) {
doc1 = PDDocument.load(is1);
merger.appendDocument(mergedPDF, doc1);
//1st file appended to main pdf");
}
ByteArrayOutputStream baos = new ByteArrayOutputStream();
mergedPDF.save(baos);
//現在要么你把它保存在這里,要么如果你想轉換成 InputStream
ByteArrayInputStream mergedInputStream = new ByteArrayInputStream(baos.toByteArray());
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