Page x of Y Java ItextPDF ver 5.5.9

[Armand Betan]

Hi Guys,

It's my first time posting here and this code is bugging me for a while now. I'm not quite sure where am I getting it wrong but I'm getting a null pointer exception whenever I run it. Everything works just fine except the part where I want to print "page x of y" in my generated PDF. I've seen different approaches all over the internet although I think the best approach would be the 2nd passing as what they call it. (although I'm not quite sure if it is really the best part). anyways here's my code, any help, criticism and code improvements are very welcome. Thank you!

@WebServlet(name = "recordsManage", urlPatterns = {"/recordsManage"})
public class recordsManage extends HttpServlet {

    Connection conn;

    public void init(ServletConfig config) throws ServletException {
        super.init(config);
        try {
            Class.forName(config.getInitParameter("jdbcClassName"));
            //System.out.println("jdbcClassName: " + config.getInitParameter("jdbcClassName"));
            String username = config.getInitParameter("dbUserName");
            String password = config.getInitParameter("dbPassword");
            String url = config.getInitParameter("jdbcDriverURL") + "://" + config.getInitParameter("dbHostName") + ":" + config.getInitParameter("dbPort") + "/" + config.getInitParameter("databaseName");
            conn = DriverManager.getConnection(url, username, password);
        } catch (SQLException sqle) {
            System.out.println("SQLException error occured - "
                    + sqle.getMessage());
        } catch (ClassNotFoundException ex) {
            Logger.getLogger(recordsManage.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        String sql = getServletConfig().getInitParameter("SQLView");
        RequestDispatcher rd;

        try {
            PreparedStatement stmt = conn.prepareStatement(sql);
            HttpSession session = request.getSession();
            HashMap userDetails = (HashMap) session.getAttribute("userDetails");
            String action = request.getParameter("action");
            String currentUser = (String) userDetails.get("username");
            String currentRole = (String) userDetails.get("role");
            stmt.setString(1, currentUser);
            ResultSet records = stmt.executeQuery();
            List Values = new ArrayList();

            switch (action) {

                case "View":
                    while (records.next()) {

                        Values.add(records.getString("USERNAME"));
                        Values.add(records.getString("PASSWORD"));
                        Values.add(records.getString("ROLE"));

                    }
                    request.setAttribute("UserList", Values);
                    rd = request.getRequestDispatcher("view.jsp");
                    rd.forward(request, response);
                    records.close();

                case "Generate":
                    String File = "/home/_/" + currentUser + ".pdf";
                    String File1 = "/home/_/" + currentUser + "_" + currentRole + ".pdf";
                    Document document = new Document(PageSize.A4);
                    PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(File));
                    writer.setBoxSize("Document", new Rectangle(PageSize.A4));
                    writer.setPageEvent(new HeaderFooter());

                    document.open();
                    DocumentContent(document, records, currentUser);
                    document.close();

                    PdfReader reader = new PdfReader(File);
                    PdfCopy writer1 = new PdfCopy(document, new FileOutputStream(File1));
                    Rectangle rectw = writer1.getBoxSize("Document");
                    document.open();
                    int pageCount = reader.getNumberOfPages();
                    for (int i = 0; i <= pageCount; i++) {
                        ColumnText.showTextAligned(writer1.getDirectContent(),
                                Element.ALIGN_CENTER, new Phrase(i + "/" + pageCount), (rectw.getLeft() + 71), rectw.getBottom() + 175, 0);
                    }
                    document.close();
                    writer1.close();

                    String genResult = "Successfully Generated PDF";
                    session.setAttribute("genResult", genResult);
                    rd = request.getRequestDispatcher("success.jsp");
                    rd.forward(request, response);
                    records.close();

            }

        } catch (SQLException ex) {
            Logger.getLogger(recordsManage.class.getName()).log(Level.SEVERE, null, ex);

        } catch (DocumentException ex) {
            Logger.getLogger(recordsManage.class.getName()).log(Level.SEVERE, null, ex);
        }

    }

    private static void DocumentContent(Document document, ResultSet records, String currentUser) throws DocumentException {

        Paragraph title = new Paragraph();
        Paragraph genUser = new Paragraph();
        Paragraph DandT = new Paragraph();
        title.add("Report Generator for Lab Exercise 6");
        title.setAlignment(Element.ALIGN_CENTER);
        addLine(title, 1);

        try {
            PdfPTable table = new PdfPTable(3);

            PdfPCell c1 = new PdfPCell(new Phrase("Username"));
            c1.setHorizontalAlignment(Element.ALIGN_CENTER);
            table.addCell(c1);

            c1 = new PdfPCell(new Phrase("Password"));
            c1.setHorizontalAlignment(Element.ALIGN_CENTER);
            table.addCell(c1);

            c1 = new PdfPCell(new Phrase("Role"));
            c1.setHorizontalAlignment(Element.ALIGN_CENTER);
            table.addCell(c1);
            table.setHeaderRows(1);

            while (records.next()) {
                table.addCell(records.getString("USERNAME"));
                table.addCell(records.getString("PASSWORD"));
                table.addCell(records.getString("ROLE"));
            }
            genUser.add("Report generated by: " + currentUser);
            DandT.add("Date and Time: " + new Date());

            document.add(title);
            document.add(table);
            document.add(genUser);
            document.add(DandT);

        } catch (SQLException ex) {
            Logger.getLogger(recordsManage.class.getName()).log(Level.SEVERE, null, ex);
        }

    }

    public class HeaderFooter extends PdfPageEventHelper {

        public void onEndPage(PdfWriter writer, Document document) {
            ServletContext context = getServletContext();
            String header = context.getInitParameter("header");
            String footer = (String) context.getAttribute("timer");
            Rectangle rect = writer.getBoxSize("Document");

            ColumnText.showTextAligned(writer.getDirectContent(),
                    Element.ALIGN_CENTER, new Phrase(header),
                    (rect.getLeft() + rect.getRight()) / 2, rect.getTop() - 16, 0);

            ColumnText.showTextAligned(writer.getDirectContent(),
                    Element.ALIGN_CENTER, new Phrase(String.format("Page %d of", writer.getPageNumber())),
                    (rect.getLeft() + 61), rect.getBottom() + 175, 0);

            ColumnText.showTextAligned(writer.getDirectContent(),
                    Element.ALIGN_CENTER, new Phrase(footer),
                    (rect.getLeft() + rect.getRight()) / 2, rect.getBottom() + 5, 0);

        }

    }

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

    }

}

[Tim Moores]

In which line of code does the exception happen? Which object or object reference is null?

You can find an example of how to add headers/footers with iText5 at https://coderanch.com/wiki/660110/iText-OpenPDF

List Values = new ArrayList();

Field names should always be lowercase in Java. Only class names are uppercase.

As an aside, be ware that iText 5 requires you to obtain a license, unless you use in conformance with the AGPL - which would mean that you must make the source code available to everyone who uses it over the network.

[Armand Betan]

Tim Moores wrote:In which line of code does the exception happen? Which object or object reference is null?

You can find an example of how to add headers/footers with iText5 at https://coderanch.com/wiki/660110/iText-OpenPDF

List Values = new ArrayList();

Field names should always be lowercase in Java. Only class names are uppercase.

As an aside, be ware that iText 5 requires you to obtain a license, unless you use in conformance with the AGPL - which would mean that you must make the source code available to everyone who uses it over the network.

Hi Tim,

Thanks for replying, I though iText5 is for free (The person who provided the jar file told me so), and this is only for a school activity, not for production or operation actually.

Regarding the null pointer exception, I'm getting it at this part of the code.

                
                    case "Generate":
                    String File = "/home/_/" + currentUser + ".pdf";
                    String File1 = "/home/_/" + currentUser + "_" + currentRole + ".pdf";
                    Document document = new Document(PageSize.A4);
                    PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(File));
                    writer.setBoxSize("Document", new Rectangle(PageSize.A4));
                    writer.setPageEvent(new HeaderFooter());
 
                    document.open();
                    DocumentContent(document, records, currentUser);
                    document.close();
 
                    PdfReader reader = new PdfReader(File);
                    PdfCopy writer1 = new PdfCopy(document, new FileOutputStream(File1));
                    Rectangle rectw = writer1.getBoxSize("Document");
                    document.open();
                    int pageCount = reader.getNumberOfPages();
                    for (int i = 0; i <= pageCount; i++) {
                        ColumnText.showTextAligned(writer1.getDirectContent(),
                                Element.ALIGN_CENTER, new Phrase(i + "/" + pageCount), (rectw.getLeft() + 71), rectw.getBottom() + 175, 0);
                    }
                    document.close();
                    writer1.close();
 
                    String genResult = "Successfully Generated PDF";
                    session.setAttribute("genResult", genResult);
                    rd = request.getRequestDispatcher("success.jsp");
                    rd.forward(request, response);
                    records.close();
 
            }
 
        } catch (SQLException ex) {
            Logger.getLogger(recordsManage.class.getName()).log(Level.SEVERE, null, ex);
 
        } catch (DocumentException ex) {
            Logger.getLogger(recordsManage.class.getName()).log(Level.SEVERE, null, ex);
        }
 
    }
 
    private static void DocumentContent(Document document, ResultSet records, String currentUser) throws DocumentException {
 
        Paragraph title = new Paragraph();
        Paragraph genUser = new Paragraph();
        Paragraph DandT = new Paragraph();
        title.add("Report Generator for Lab Exercise 6");
        title.setAlignment(Element.ALIGN_CENTER);
        addLine(title, 1);
 
        try {
            PdfPTable table = new PdfPTable(3);
 
            PdfPCell c1 = new PdfPCell(new Phrase("Username"));
            c1.setHorizontalAlignment(Element.ALIGN_CENTER);
            table.addCell(c1);
 
            c1 = new PdfPCell(new Phrase("Password"));
            c1.setHorizontalAlignment(Element.ALIGN_CENTER);
            table.addCell(c1);
 
            c1 = new PdfPCell(new Phrase("Role"));
            c1.setHorizontalAlignment(Element.ALIGN_CENTER);
            table.addCell(c1);
            table.setHeaderRows(1);
 
            while (records.next()) {
                table.addCell(records.getString("USERNAME"));
                table.addCell(records.getString("PASSWORD"));
                table.addCell(records.getString("ROLE"));
            }
            genUser.add("Report generated by: " + currentUser);
            DandT.add("Date and Time: " + new Date());
 
            document.add(title);
            document.add(table);
            document.add(genUser);
            document.add(DandT);
 
        } catch (SQLException ex) {
            Logger.getLogger(recordsManage.class.getName()).log(Level.SEVERE, null, ex);
        }
 
    }
 
    public class HeaderFooter extends PdfPageEventHelper {
 
        public void onEndPage(PdfWriter writer, Document document) {
            ServletContext context = getServletContext();
            String header = context.getInitParameter("header");
            String footer = (String) context.getAttribute("timer");
            Rectangle rect = writer.getBoxSize("Document");
 
            ColumnText.showTextAligned(writer.getDirectContent(),
                    Element.ALIGN_CENTER, new Phrase(header),
                    (rect.getLeft() + rect.getRight()) / 2, rect.getTop() - 16, 0);
 
            ColumnText.showTextAligned(writer.getDirectContent(),
                    Element.ALIGN_CENTER, new Phrase(String.format("Page %d of", writer.getPageNumber())),
                    (rect.getLeft() + 61), rect.getBottom() + 175, 0);
 
            ColumnText.showTextAligned(writer.getDirectContent(),
                    Element.ALIGN_CENTER, new Phrase(footer),
                    (rect.getLeft() + rect.getRight()) / 2, rect.getBottom() + 5, 0);
 
        }
 
    }
 
    private static void addLine(Paragraph paragraph, int number) {
        for (int i = 0; i < number; i++) {
            paragraph.add(new Paragraph(" "));
        }
 
    }
 
}

I'm getting a nullpointer whenever the program executes this line;

for (int i = 0; i <= pageCount; i++) {
                        ColumnText.showTextAligned(writer1.getDirectContent(),
                                Element.ALIGN_CENTER, new Phrase(i + "/" + pageCount), (rectw.getLeft() + 71), rectw.getBottom() + 175, 0);
                    }

                    PdfReader reader = new PdfReader(File);
                    PdfCopy writer1 = new PdfCopy(document, new FileOutputStream(File1));
                    Rectangle rectw = writer1.getBoxSize("Document");
                    document.open();
                    int pageCount = reader.getNumberOfPages();
                    for (int i = 0; i <= pageCount; i++) {
                        ColumnText.showTextAligned(writer1.getDirectContent(),
                                Element.ALIGN_CENTER, new Phrase(i + "/" + pageCount), (rectw.getLeft() + 71), rectw.getBottom() + 175, 0);
                    }
                    document.close();
                    writer1.close();
 
                    String genResult = "Successfully Generated PDF";
                    session.setAttribute("genResult", genResult);
                    rd = request.getRequestDispatcher("success.jsp");
                    rd.forward(request, response);
                    records.close();

[Tim Moores]

I though iText5 is for free (The person who provided the jar file told me so), and this is only for a school activity, not for production or operation actually.

It matters not - whoever gets PDFs created by iText5 under the AGPL must be provided access to the source code if he asks. You should always check the license of software you use. As you have seen, what other people tell you can be wrong.

I'm getting a nullpointer whenever the program executes this line

We can't tell from that where the error happens - post the full stack trace of the exception. You can debug the issue by checking all object for null before using them.

[Armand Betan]

Tim Moores wrote:

I though iText5 is for free (The person who provided the jar file told me so), and this is only for a school activity, not for production or operation actually.

It matters not - whoever gets PDFs created by iText5 under the AGPL must be provided access to the source code if he asks. You should always check the license of software you use. As you have seen, what other people tell you can be wrong.

I'm getting a nullpointer whenever the program executes this line

We can't tell from that where the error happens - post the full stack trace of the exception. You can debug the issue by checking all object for null before using them.

Thank you Tim for your reply.

I'll keep that in mind with the AGPL license for Itext PDF, I fairly new with the technicalities of Software Engineering so I'm not much used to discussion licenses.

With regards to my program, I was able to find a solution by creating another function doing a second pass method to the generated PDF. I would happy to share my source code if someone needs it in the future.