Java Tutorial/PDF/Introduction

Create Empty page

import java.io.FileOutputStream;
import com.lowagie.text.Document;
import com.lowagie.text.Paragraph;
import com.lowagie.text.pdf.PdfWriter;
public class MainClass {
  public static void main(String[] args) throws Exception {
    Document document = new Document();
    PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream("2.pdf"));
    document.open();
    writer.setPageEmpty(true);
    document.newPage();
    writer.setPageEmpty(false);
    document.newPage();
    document.add(new Paragraph("Hello World"));
    document.newPage();
    writer.setPageEmpty(true);
    document.newPage();
    document.close();
  }
}

Create your first Pdf document with Java

import java.io.FileOutputStream;
import com.lowagie.text.Document;
import com.lowagie.text.Paragraph;
import com.lowagie.text.pdf.PdfWriter;
public class GeneratesPDFFileWithText {
  public static void main(String[] args) throws Exception {
    Document document = new Document();
    PdfWriter.getInstance(document, new FileOutputStream("HelloWorld.pdf"));
    document.open();
    document.add(new Paragraph("Hello World"));
    document.close();
  }
}

inspects a PDF file

import java.io.FileOutputStream;
import java.io.PrintStream;
import java.util.Iterator;
import com.lowagie.text.pdf.PRStream;
import com.lowagie.text.pdf.PRTokeniser;
import com.lowagie.text.pdf.PdfArray;
import com.lowagie.text.pdf.PdfDictionary;
import com.lowagie.text.pdf.PdfIndirectReference;
import com.lowagie.text.pdf.PdfLister;
import com.lowagie.text.pdf.PdfName;
import com.lowagie.text.pdf.PdfObject;
import com.lowagie.text.pdf.PdfReader;
public class MainClass {
  public static void main(String[] args) throws Exception {
    PdfReader reader = new PdfReader("2.pdf");
    PrintStream list = new PrintStream(new FileOutputStream("2.txt"));
    PdfLister lister = new PdfLister(new PrintStream(list));
    PdfDictionary trailer = reader.getTrailer();
    lister.listDict(trailer);
    PdfIndirectReference info = (PdfIndirectReference) trailer.get(PdfName.INFO);
    lister.listAnyObject(info);
    lister.listAnyObject(reader.getPdfObject(info.getNumber()));
    PdfDictionary root = reader.getCatalog();
    lister.listDict(root);
    PdfDictionary outlines = (PdfDictionary) reader.getPdfObject(((PdfIndirectReference) root
        .get(PdfName.OUTLINES)).getNumber());
    lister.listDict(outlines);
    PdfObject first = reader.getPdfObject(((PdfIndirectReference) outlines.get(PdfName.FIRST))
        .getNumber());
    lister.listAnyObject(first);
    PdfDictionary pages = (PdfDictionary) reader.getPdfObject(((PdfIndirectReference) root
        .get(PdfName.PAGES)).getNumber());
    lister.listDict(pages);
    PdfArray kids = (PdfArray) pages.get(PdfName.KIDS);
    PdfIndirectReference kid_ref;
    PdfDictionary kid = null;
    for (Iterator i = kids.getArrayList().iterator(); i.hasNext();) {
      kid_ref = (PdfIndirectReference) i.next();
      kid = (PdfDictionary) reader.getPdfObject(kid_ref.getNumber());
      lister.listDict(kid);
    }
    PdfIndirectReference content_ref = (PdfIndirectReference) kid.get(PdfName.CONTENTS);
    PRStream content = (PRStream) reader.getPdfObject(content_ref.getNumber());
    lister.listDict(content);
    byte[] contentstream = PdfReader.getStreamBytes(content);
    list.println(new String(contentstream));
    PRTokeniser tokenizer = new PRTokeniser(contentstream);
    while (tokenizer.nextToken()) {
      if (tokenizer.getTokenType() == PRTokeniser.TK_STRING) {
        list.println(tokenizer.getStringValue());
      }
    }
  }
}

PdfDictionary

import java.io.FileOutputStream;
import com.lowagie.text.Document;
import com.lowagie.text.PageSize;
import com.lowagie.text.pdf.BaseFont;
import com.lowagie.text.pdf.PRIndirectReference;
import com.lowagie.text.pdf.PRStream;
import com.lowagie.text.pdf.PRTokeniser;
import com.lowagie.text.pdf.PdfContentByte;
import com.lowagie.text.pdf.PdfDictionary;
import com.lowagie.text.pdf.PdfName;
import com.lowagie.text.pdf.PdfReader;
import com.lowagie.text.pdf.PdfTemplate;
import com.lowagie.text.pdf.PdfWriter;
public class MainClass {
  public static void main(String[] args) throws Exception {
    Document document = new Document(PageSize.A6);
    PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream("2.pdf"));
    document.open();
    PdfContentByte cb = writer.getDirectContent();
    BaseFont bf = BaseFont.createFont(BaseFont.HELVETICA, BaseFont.CP1252, BaseFont.NOT_EMBEDDED);
    cb.beginText();
    cb.setFontAndSize(bf, 12);
    cb.moveText(88.66f, 367);
    cb.showText("ld");
    cb.endText();
    PdfTemplate tmp = cb.createTemplate(250, 25);
    tmp.beginText();
    tmp.setFontAndSize(bf, 12);
    tmp.moveText(0, 7);
    tmp.showText("Hello People");
    tmp.endText();
    cb.addTemplate(tmp, 36, 343);
    document.close();
    PdfReader reader = new PdfReader("2.pdf");
    PdfDictionary page = reader.getPageN(1);
    PRIndirectReference objectReference = (PRIndirectReference) page.get(PdfName.CONTENTS);
    PRStream stream = (PRStream) PdfReader.getPdfObject(objectReference);
    byte[] streamBytes = PdfReader.getStreamBytes(stream);
    PRTokeniser tokenizer = new PRTokeniser(streamBytes);
    while (tokenizer.nextToken()) {
      if (tokenizer.getTokenType() == PRTokeniser.TK_STRING) {
        System.out.println(tokenizer.getStringValue());
      }
    }
  }
}

PRTokeniser

import java.io.FileOutputStream;
import com.lowagie.text.Document;
import com.lowagie.text.PageSize;
import com.lowagie.text.Paragraph;
import com.lowagie.text.pdf.PRIndirectReference;
import com.lowagie.text.pdf.PRStream;
import com.lowagie.text.pdf.PRTokeniser;
import com.lowagie.text.pdf.PdfContentByte;
import com.lowagie.text.pdf.PdfDictionary;
import com.lowagie.text.pdf.PdfName;
import com.lowagie.text.pdf.PdfReader;
import com.lowagie.text.pdf.PdfWriter;
public class MainClass {
  public static void main(String[] args) throws Exception {
    Document document = new Document(PageSize.A6);
    PdfWriter.getInstance(document, new FileOutputStream("2.pdf"));
    document.open();
    document.add(new Paragraph("Hello World"));
    document.add(new Paragraph("Hello People"));
    document.close();
    PdfReader reader = new PdfReader("2.pdf");
    PdfDictionary page = reader.getPageN(1);
    PRIndirectReference objectReference = (PRIndirectReference) page.get(PdfName.CONTENTS);
    PRStream stream = (PRStream) PdfReader.getPdfObject(objectReference);
    byte[] streamBytes = PdfReader.getStreamBytes(stream);
    String contentStream = new String(streamBytes);
    System.out.println(contentStream);
    PRTokeniser tokenizer = new PRTokeniser(streamBytes);
    while (tokenizer.nextToken()) {
      if (tokenizer.getTokenType() == PRTokeniser.TK_STRING) {
        System.out.println(tokenizer.getStringValue());
      }
    }
    StringBuffer buf = new StringBuffer();
    int pos = contentStream.indexOf("Hello World") + 11;
    buf.append(contentStream.substring(0, pos));
    buf.append("Hello");
    buf.append(contentStream.substring(pos));
    String hackedContentStream = buf.toString();
    document = new Document(PageSize.A6);
    PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(
        "HelloWorldStreamHacked.pdf"));
    document.open();
    PdfContentByte cb = writer.getDirectContent();
    cb.setLiteral(hackedContentStream);
    document.close();
  }
}

Read Pdf document to string

import java.io.FileOutputStream;
import com.lowagie.text.Document;
import com.lowagie.text.PageSize;
import com.lowagie.text.Paragraph;
import com.lowagie.text.pdf.PdfReader;
import com.lowagie.text.pdf.PdfStamper;
import com.lowagie.text.pdf.PdfWriter;
public class MainClass {
  public static void main(String[] args) throws Exception {
    Document document = new Document(PageSize.A6);
    PdfWriter.getInstance(document, new FileOutputStream("2.pdf"));
    document.open();
    document.add(new Paragraph("Hello World"));
    document.add(new Paragraph("Hello People"));
    document.close();
    PdfReader reader = new PdfReader("2.pdf");
    byte[] streamBytes = reader.getPageContent(1);
    String contentStream = new String(streamBytes);
    System.out.println(contentStream);
    StringBuffer buf = new StringBuffer();
    int pos = contentStream.indexOf("Hello World") + 11;
    buf.append(contentStream.substring(0, pos));
    buf.append(", Hello ");
    buf.append(contentStream.substring(pos));
    String hackedContentStream = buf.toString();
    PdfStamper stamper = new PdfStamper(reader, new FileOutputStream("HelloWorldStreamHack.pdf"));
    reader.setPageContent(1, hackedContentStream.getBytes());
    stamper.close();
  }
}

Tagged PDF

import java.io.FileOutputStream;
import com.lowagie.text.Document;
import com.lowagie.text.pdf.BaseFont;
import com.lowagie.text.pdf.PdfContentByte;
import com.lowagie.text.pdf.PdfName;
import com.lowagie.text.pdf.PdfStructureElement;
import com.lowagie.text.pdf.PdfStructureTreeRoot;
import com.lowagie.text.pdf.PdfWriter;
public class MainClass {
  public static void main(String[] args) throws Exception {
    Document document = new Document();
    PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream("2.pdf"));
    writer.setTagged();
    document.open();
    PdfStructureTreeRoot root = writer.getStructureTreeRoot();
    PdfStructureElement eTop = new PdfStructureElement(root, new PdfName("Everything"));
    root.mapRole(new PdfName("Everything"), new PdfName("Sect"));
    PdfStructureElement e1 = new PdfStructureElement(eTop, PdfName.P);
    PdfStructureElement e2 = new PdfStructureElement(eTop, PdfName.P);
    PdfStructureElement e3 = new PdfStructureElement(eTop, PdfName.P);
    PdfContentByte cb = writer.getDirectContent();
    BaseFont bf = BaseFont.createFont(BaseFont.HELVETICA, BaseFont.WINANSI, false);
    cb.setLeading(16);
    cb.setFontAndSize(bf, 12);
    cb.beginText();
    cb.setTextMatrix(50, 700);
    for (int k = 0; k < 2; ++k) {
      cb.beginMarkedContentSequence(e2);
      cb.newlineShowText("text2");
      cb.endMarkedContentSequence();
    }
    cb.endText();
    document.newPage();
    cb.setLeading(16);
    cb.setFontAndSize(bf, 12);
    cb.beginText();
    cb.setTextMatrix(50, 804);
    cb.beginMarkedContentSequence(e2);
    cb.newlineShowText("text2");
    cb.endMarkedContentSequence();
    cb.endText();
    cb.beginMarkedContentSequence(e3);
    cb.endMarkedContentSequence();
    document.close();
  }
}

Update a Pdf document

import java.io.FileOutputStream;
import com.lowagie.text.Document;
import com.lowagie.text.Element;
import com.lowagie.text.Paragraph;
import com.lowagie.text.pdf.BaseFont;
import com.lowagie.text.pdf.PdfContentByte;
import com.lowagie.text.pdf.PdfReader;
import com.lowagie.text.pdf.PdfStamper;
import com.lowagie.text.pdf.PdfWriter;
public class MainClass {
  public static void main(String[] args) throws Exception {
    Document.rupress = false;
    Document document = new Document();
    PdfWriter.getInstance(document, new FileOutputStream("2.pdf"));
    document.open();
    document.add(new Paragraph("Hello World"));
    document.close();
    PdfReader reader = new PdfReader("HelloWorld.pdf");
    PdfStamper stamper = new PdfStamper(reader, new FileOutputStream("updated.pdf"), "\0", true);
    PdfContentByte cb = stamper.getOverContent(1);
    cb.beginText();
    cb.showTextAligned(Element.ALIGN_LEFT, "Hello People", 36, 770, 0);
    cb.endText();
    stamper.close();
  }
}