iText - add content to existing PDF file

Question

I want to do the following with iText:

(1) parse an existing PDF file

(2) add some data to it, on the existing single page of the document (such as a timesta

Answer 1

Document document = new Document();
    PdfWriter writer = PdfWriter.getInstance(document, 
        new FileOutputStream("E:/TextFieldForm.pdf"));
    document.open();

    PdfPTable table = new PdfPTable(2);
    table.getDefaultCell().setPadding(5f); // Code 1
    table.setHorizontalAlignment(Element.ALIGN_LEFT);
    PdfPCell cell;      

    // Code 2, add name TextField       
    table.addCell("Name"); 
    TextField nameField = new TextField(writer, 
        new Rectangle(0,0,200,10), "nameField");
    nameField.setBackgroundColor(Color.WHITE);
    nameField.setBorderColor(Color.BLACK);
    nameField.setBorderWidth(1);
    nameField.setBorderStyle(PdfBorderDictionary.STYLE_SOLID);
    nameField.setText("");
    nameField.setAlignment(Element.ALIGN_LEFT);
    nameField.setOptions(TextField.REQUIRED);               
    cell = new PdfPCell();
    cell.setMinimumHeight(10);
    cell.setCellEvent(new FieldCell(nameField.getTextField(), 
        200, writer));
    table.addCell(cell);

    // force upper case javascript
    writer.addJavaScript(
        "var nameField = this.getField('nameField');" +
        "nameField.setAction('Keystroke'," +
        "'forceUpperCase()');" +
        "" +
        "function forceUpperCase(){" +
        "if(!event.willCommit)event.change = " +
        "event.change.toUpperCase();" +
        "}");


    // Code 3, add empty row
    table.addCell("");
    table.addCell("");


    // Code 4, add age TextField
    table.addCell("Age");
    TextField ageComb = new TextField(writer, new Rectangle(0,
         0, 30, 10), "ageField");
    ageComb.setBorderColor(Color.BLACK);
    ageComb.setBorderWidth(1);
    ageComb.setBorderStyle(PdfBorderDictionary.STYLE_SOLID);
    ageComb.setText("12");
    ageComb.setAlignment(Element.ALIGN_RIGHT);
    ageComb.setMaxCharacterLength(2);
    ageComb.setOptions(TextField.COMB | 
        TextField.DO_NOT_SCROLL);
    cell = new PdfPCell();
    cell.setMinimumHeight(10);
    cell.setCellEvent(new FieldCell(ageComb.getTextField(), 
        30, writer));
    table.addCell(cell);

    // validate age javascript
    writer.addJavaScript(
        "var ageField = this.getField('ageField');" +
        "ageField.setAction('Validate','checkAge()');" +
        "function checkAge(){" +
        "if(event.value < 12){" +
        "app.alert('Warning! Applicant\\'s age can not" +
        " be younger than 12.');" +
        "event.value = 12;" +
        "}}");      



    // add empty row
    table.addCell("");
    table.addCell("");


    // Code 5, add age TextField
    table.addCell("Comment");
    TextField comment = new TextField(writer, 
        new Rectangle(0, 0,200, 100), "commentField");
    comment.setBorderColor(Color.BLACK);
    comment.setBorderWidth(1);
    comment.setBorderStyle(PdfBorderDictionary.STYLE_SOLID);
    comment.setText("");
    comment.setOptions(TextField.MULTILINE | 
        TextField.DO_NOT_SCROLL);
    cell = new PdfPCell();
    cell.setMinimumHeight(100);
    cell.setCellEvent(new FieldCell(comment.getTextField(), 
        200, writer));
    table.addCell(cell);


    // check comment characters length javascript
    writer.addJavaScript(
        "var commentField = " +
        "this.getField('commentField');" +
        "commentField" +
        ".setAction('Keystroke','checkLength()');" +
        "function checkLength(){" +
        "if(!event.willCommit && " +
        "event.value.length > 100){" +
        "app.alert('Warning! Comment can not " +
        "be more than 100 characters.');" +
        "event.change = '';" +
        "}}");          

    // add empty row
    table.addCell("");
    table.addCell("");


    // Code 6, add submit button    
    PushbuttonField submitBtn = new PushbuttonField(writer,
            new Rectangle(0, 0, 35, 15),"submitPOST");
    submitBtn.setBackgroundColor(Color.GRAY);
    submitBtn.
        setBorderStyle(PdfBorderDictionary.STYLE_BEVELED);
    submitBtn.setText("POST");
    submitBtn.setOptions(PushbuttonField.
        VISIBLE_BUT_DOES_NOT_PRINT);
    PdfFormField submitField = submitBtn.getField();
    submitField.setAction(PdfAction
    .createSubmitForm("",null, PdfAction.SUBMIT_HTML_FORMAT));

    cell = new PdfPCell();
    cell.setMinimumHeight(15);
    cell.setCellEvent(new FieldCell(submitField, 35, writer));
    table.addCell(cell);



    // Code 7, add reset button
    PushbuttonField resetBtn = new PushbuttonField(writer,
            new Rectangle(0, 0, 35, 15), "reset");
    resetBtn.setBackgroundColor(Color.GRAY);
    resetBtn.setBorderStyle(
        PdfBorderDictionary.STYLE_BEVELED);
    resetBtn.setText("RESET");
    resetBtn
    .setOptions(
        PushbuttonField.VISIBLE_BUT_DOES_NOT_PRINT);
    PdfFormField resetField = resetBtn.getField();
    resetField.setAction(PdfAction.createResetForm(null, 0));
    cell = new PdfPCell();
    cell.setMinimumHeight(15);
    cell.setCellEvent(new FieldCell(resetField, 35, writer));
    table.addCell(cell);        

    document.add(table);
    document.close();
}


class FieldCell implements PdfPCellEvent{

    PdfFormField formField;
    PdfWriter writer;
    int width;

    public FieldCell(PdfFormField formField, int width, 
        PdfWriter writer){
        this.formField = formField;
        this.width = width;
        this.writer = writer;
    }

    public void cellLayout(PdfPCell cell, Rectangle rect, 
        PdfContentByte[] canvas){
        try{
            // delete cell border
            PdfContentByte cb = canvas[PdfPTable
                .LINECANVAS];
            cb.reset();

            formField.setWidget(
                new Rectangle(rect.left(), 
                    rect.bottom(), 
                    rect.left()+width, 
                    rect.top()), 
                    PdfAnnotation
                    .HIGHLIGHT_NONE);

            writer.addAnnotation(formField);
        }catch(Exception e){
            System.out.println(e);
        }
    }
}