PDF creation is required in some of Java-based applications, as PDF is one of the most popular document types due to its read-only and platform-independent attributes. iText is an open source library that helps integrate the PDF functionalities (create/manipulate) in your application.

iText has classes as Document objects, which are basically the main containers, and other classes are residing within them. Paragraph is a content type that can be written to the Document object. Other content types are Anchor, Chapter,  Phrase,  PdfpTable, Section, List, etc. These classes help create a PDF document.

Let's look at the working example.

Required JAR: itextpdf-5.1.0.jar

DataObject.java:

package com.test.pdf;

public class DataObject {
    private String year;
    private String income;
    private String comanyName;

    public String getYear() {
        return year;
    }
    public void setYear(String year) {
        this.year = year;
    }
    public String getIncome() {
        return income;
    }
    public void setIncome(String income) {
        this.income = income;
    }
    public String getComanyName() {
        return comanyName;
    }
    public void setComanyName(String comanyName) {
        this.comanyName = comanyName;
    }
}

HeaderFooter.java:

package com.test.pdf;

import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.Element;
import com.itextpdf.text.ExceptionConverter;
import com.itextpdf.text.Phrase;
import com.itextpdf.text.Rectangle;
import com.itextpdf.text.pdf.ColumnText;
import com.itextpdf.text.pdf.PdfPTable;
import com.itextpdf.text.pdf.PdfPageEventHelper;
import com.itextpdf.text.pdf.PdfTemplate;
import com.itextpdf.text.pdf.PdfWriter;

class HeaderFooter extends PdfPageEventHelper {

    /** The header/footer text. */
    String header;

    /** The template with the total number of pages. */
    PdfTemplate total;

    /**
     * Allows us to change the content of the header.
     * @param header The new header String
     */
    public void setHeader(String header) {
        this.header = header;
    }

    /**
     * Creates the PdfTemplate that will hold the total number of pages
     */
    public void onOpenDocument(PdfWriter writer, Document document) {
        total = writer.getDirectContent().createTemplate(25, 16);
    }

    /**
     * Adds a header to every page
     */
    public void onEndPage(PdfWriter writer, Document document) {
        PdfPTable table = new PdfPTable(2);
        try {
            table.setWidths(new int[]{200, 30});
            table.setLockedWidth(true);
            table.getDefaultCell().setBorder(Rectangle.SUBJECT);
            table.addCell(header);
            table.addCell(String.format("Page %d ", writer.getPageNumber()));

            Rectangle page = document.getPageSize();

            table.setTotalWidth(page.getWidth() - document.leftMargin() - document.rightMargin());
            table.writeSelectedRows(0, -1, document.leftMargin(), page.getHeight() - document.topMargin()
                    + table.getTotalHeight()+5, writer.getDirectContent());          
        }
        catch(DocumentException de) {
            throw new ExceptionConverter(de);
        }
    }

    /**
     * Fills out the total number of pages before the document is closed
     */
    public void onCloseDocument(PdfWriter writer, Document document) {
        ColumnText.showTextAligned(total, Element.ALIGN_LEFT,
                new Phrase(String.valueOf(writer.getPageNumber() - 1)), 2, 2, 0);
    }
}  

PdfCreater.java:

package com.test.pdf;

import java.util.Date;
import java.util.List;
import com.itextpdf.text.BadElementException;
import com.itextpdf.text.BaseColor;
import com.itextpdf.text.Chunk;
import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.Element;
import com.itextpdf.text.Font;
import com.itextpdf.text.Paragraph;
import com.itextpdf.text.Phrase;
import com.itextpdf.text.pdf.PdfPCell;
import com.itextpdf.text.pdf.PdfPTable;

/**
 * This is to create a PDF file.
 */
public class PDFCreator {

    private final static String[] HEADER_ARRAY = {"S.No.", "CompanyName", "Income", "Year"};
    public final static Font SMALL_BOLD = new Font(Font.FontFamily.TIMES_ROMAN, 8,
            Font.BOLD);
    public final static Font NORMAL_FONT = new Font(Font.FontFamily.TIMES_ROMAN, 8,
            Font.NORMAL);

    public static void addMetaData(Document document, String sqlXMLFileName) {
        document.addTitle("Sample Report");
        document.addSubject("Using iText");
        document.addAuthor("Arun");
    }

    public static void addContent(Document document, List<DataObject> dataObjList) throws DocumentException {
        Paragraph paragraph = new Paragraph();
        paragraph.setFont(NORMAL_FONT);
        createReportTable(paragraph, dataObjList);
        document.add(paragraph);
    }

    private static void createReportTable(Paragraph paragraph, List<DataObject> dataObjList)
    throws BadElementException {

        PdfPTable table = new PdfPTable(4);
        table.setWidthPercentage(100);
        paragraph.add(new Chunk("Report Table :- ", SMALL_BOLD));

        if(null == dataObjList){
            paragraph.add(new Chunk("No data to display."));
            return;
        }
        addHeaderInTable(HEADER_ARRAY, table);

        int count = 1;

        for(DataObject dataObject : dataObjList){
            addToTable(table, String.valueOf(count)+".");
            addToTable(table, dataObject.getComanyName());
            addToTable(table, dataObject.getIncome());
            addToTable(table, dataObject.getYear());
            count++;
        }
        paragraph.add(table);
    }

    /** Helper methods start here **/  
    public static void addTitlePage(Document document, String title) throws DocumentException {

        Paragraph preface = new Paragraph();
        addEmptyLine(preface, 3);
        preface.add(new Phrase("Test Report: ", NORMAL_FONT));
        preface.add(new Phrase(title, PDFCreator.NORMAL_FONT));

        addEmptyLine(preface, 1);
        preface.add(new Phrase("Date: ", PDFCreator.SMALL_BOLD));
        preface.add(new Phrase(new Date().toString(), PDFCreator.NORMAL_FONT));
        addEmptyLine(preface, 1);
        preface.add(new Phrase("Report generated by: ", PDFCreator.SMALL_BOLD));
        preface.add(new Phrase("Arun", PDFCreator.NORMAL_FONT));
        addEmptyLine(preface, 2);
        preface.add(new Phrase("This is basically a sample report.", PDFCreator.NORMAL_FONT));

        document.addSubject("PDF : " + title);
        preface.setAlignment(Element.ALIGN_CENTER);
        document.add(preface);
        document.newPage();
    }

    public static void addEmptyLine(Paragraph paragraph, int number) {
        for (int i = 0; i < number; i++) {
            paragraph.add(new Paragraph(" "));
        }
    }

    public static void addHeaderInTable(String[] headerArray, PdfPTable table){

        PdfPCell c1 = null;
        for(String header : headerArray) {
            c1 = new PdfPCell(new Phrase(header, PDFCreator.SMALL_BOLD));
            c1.setBackgroundColor(BaseColor.GREEN);
            c1.setHorizontalAlignment(Element.ALIGN_CENTER);
            table.addCell(c1);
        }
        table.setHeaderRows(1);
    }

    public static void addToTable(PdfPTable table, String data){        
        table.addCell(new Phrase(data, PDFCreator.NORMAL_FONT));
    }

    public static Paragraph getParagraph(){        
        Paragraph paragraph = new Paragraph();
        paragraph.setFont(PDFCreator.NORMAL_FONT);
        addEmptyLine(paragraph, 1);
        return paragraph;
    }
} 

Client.java:

package com.test.pdf;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.util.ArrayList;
import java.util.List;
import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.PageSize;
import com.itextpdf.text.pdf.PdfWriter;

public class Client {
    private static final String TITLE = "TestReport";
    public static final String PDF_EXTENSION = ".pdf";

    public static void main(String[] args) {          

        List<DataObject> dataObjList = getDataObjectList();
        Document document = null;
        try {
        //Document is not auto-closable hence need to close it separately
            document = new Document(PageSize.A4);            

            PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(
                    new File(TITLE + PDF_EXTENSION)));
            HeaderFooter event = new HeaderFooter();
            event.setHeader("Test Report");
            writer.setPageEvent(event);
            document.open();
            PDFCreator.addMetaData(document, TITLE);
            PDFCreator.addTitlePage(document, TITLE);
            PDFCreator.addContent(document, dataObjList);
        }catch (DocumentException | FileNotFoundException e) {
            e.printStackTrace();
            System.out.println("FileNotFoundException occurs.." + e.getMessage());
        }finally{
            if(null != document){
                document.close();
            }
        }
    }

    public static List<DataObject> getDataObjectList(){

        List<DataObject> dataObjList = new ArrayList<DataObject>();
        DataObject d1 = new DataObject();
        d1.setComanyName("ABC");
        d1.setIncome("20000");
        d1.setYear("2017");

        DataObject d2 = new DataObject();
        d2.setComanyName("XYZ");
        d2.setIncome("30000");
        d2.setYear("2017");

        dataObjList.add(d1);
        dataObjList.add(d2);
        return dataObjList;    
    }
}

Now we are all set; simply run Client.java and you can see the generated PDF file named as 'TestReport.pdf'.

Happy Learning!