iText7添加页眉、页脚

因为iText5对部分pdf操作的支持没有iText7的多，所以后续将项目原本用的itext5升级到了iText7，本文就整理一下iText7添加页眉和页脚的实现。
iText7修改实现IEventHandler,重写handlerEvent方法进行处理，然后addEventHandler到PdfDocment，并指定触发事件的类型。
还是以下边的页眉页脚为例：
页眉: 左边为logo，右边报告简称；
页脚：左边为导出人名，中间为页码，右边为导出日期；
将页眉和页脚都放在在表格里边，然后页眉仅显示底部边框，页脚仅显示顶部边框，做到分割线的作用。
注意点就是总页码，总页码是动态，只有到了写完整个文档，才能知道总页码，iText7修改为使用PdfFormXObject，并且需要在关闭文档前，手动调用。

版本号及maven依赖

PdfHeaderFooterEvent

@Slf4j
public class PdfHeaderFooterEvent extends IEventHandler {private final static String FONT_PATH = "C:\Windows\Fonts\simsun.ttc,0";private final static BaseFont BASE_FONT = BaseFont.createFont(FONT_PATH, BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED);private final static String logoPath = "D:\Users\admin\Downloads\logo.png";//总页码使用的模板对象public PdfFormXObject totalNumTemplate = null ;/*** 事件处理*/@Overridepublic void handlerEvent(Event event){final PdfDocumentEvent docEvent = (PdfDocumentEvent) event;final PdfDocument pdfDoc = docEvent.getDocument();final Document doc = new Document(pdfDoc);final PdfPage page = docEvent.getPage();final Rectangle pageSize = page.getPageSize();final int pageNumber = pdfDoc.getPageNumber(page);final float pdfHeight = pageSize.getHeight();try{this.addPageHeader(doc, pdfHeight);}catch(Exception e){log.error("添加页眉出错", e);}try{this.addPageFooter(doc, pdfDoc, page);}catch(Exception e){log.error("添加页脚出错", e);}}/*** 页眉*/private void addPageHeader(Document docment, float pdfHeight){//创建字体Font textFont = new Font(BASE_FONT, 10f);float width = PageSize.A4.getWidth()-60;//表格 一行两列Table table = new Table(2);table.setWidth(width);//logoImage logo = new Image(ImageDataFactory.create(logoPath));table.addCell(new Cell().add(logo).setHeight(40).setBorderTop(Border.NO_BORDER).setBorderLeft(Border.NO_BORDER).setBorderRight(Border.NO_BORDER));//名称Paragraph nameP = new Paragraph("test").setFont(textFont).setFontSize(10f);table.addCell(new Cell().add(nameP).setHorizontalAlignment(HorizontalAlignment.RIGHT).setVerticalAlignment(VerticalAlignment.MIDDLE).setTextAlignment(TextAlignment.RIGHT).setBorderTop(Border.NO_BORDER).setBorderLeft(Border.NO_BORDER).setBorderRight(Border.NO_BORDER));//设置表格的位置 页眉处table.setFixedPosition(document.getLeftMargin()-10, pdfHeight-document.getTopMargin()-40, table.getWidth());document.add(table);}/*** 页脚*/private void addPageFooter(Document docment, PdfDocument pdf, PdfPage page){Rectangle pageSize = page.getPageSize();//创建字体Font textFont = new Font(BASE_FONT, 10f);float width = PageSize.A4.getWidth()-60;//表格 一行两列Table table = new Table(3);table.setWidth(width);//导入人Paragraph nameP = new Paragraph("admin").setFont(textFont).setFontSize(10f);table.addCell(new Cell().add(nameP).setBorderBottom(Border.NO_BORDER).setBorderLeft(Border.NO_BORDER).setBorderRight(Border.NO_BORDER));//页码 居右if(null == totalNumTemplate){totalNumTemplate = new PdfFormXObject(new Rectangle(0,0,20,20));}int pageNum = pdf.getPageNumber(page);PdfCanvas canvasP = new PdfCanvas(page);Canvas canvas = new Canvas(canvasP, pageSize);canvas.setFontSize(10f);Paragraph pageP = new Paragraph(pageNum).add(" / ").setFont(textFont).setFontSize(10f);canvas.showTextAligned(pageP, 295, 10, TextAlignment.RIGHT);canvas.close();canvasP.addXObjectAt(totalNumTemplate, 300f, 7f);canvasP.release();//日期Paragraph dateP = new Paragraph("2022/09/30").setFont(textFont).setFontSize(10f);table.addCell(new Cell().add(dateP).setBorderBottom(Border.NO_BORDER).setBorderLeft(Border.NO_BORDER).setBorderRight(Border.NO_BORDER));table.setFixedPosition(document.getLeftMargin()-10, pdfHeight-document.getBottomMargin()-40, table.getWidth());document.add(table);}/*** 文档关闭  手动调用*/public void closeDocument(PdfDocument docment){//修改总页码  居左Canvas canvas = new Canvas(totalNumTemplate, docment);canvas.setFontSize(10f);canvas.showTextAligned(Integer.toString(docment.getNumberOfPages(),0,3f,TextAlignment.LEFT));canvas.close();}
}

PdfTest

public class PdfTest{public static void main(String[] args){String pdfPath = "test.pdf";PdfWriter writer = PdfWriter.getInstance(docment, new FileOutputStream(pdfPath));PdfDocument pdfDoc = new PdfDocument(writer);Document docment = new Documnet(pdfDoc);PdfHeaderFooterEvent event = new PdfHeaderFooterEvent();pdfDoc.addEventHandler(PdfDocumentEvent.END_PAGE, event);document.add(new Paragraph("test  contents"));event.closeDocument(pdfDoc);document.close();}
}

以上就是iText7添加页脚页眉的全部伪代码逻辑。