iText7 学习笔记2--页眉页脚

创建PDF文档，页眉页脚是必不可少的一环，页面页脚的作用一般是会存放一些固定的信息，例如当前页面的章节名称，公司logo，页码等等，我这里以下图为例：

位置： 1 ： 显示当前页面的所在的版块名称，例如一本书的第几章等

            2： 显示当前的用户名或作者之类

            3：logo图片

             4：当前页码

一、事件

       页眉页脚在每一页的布局和逻辑都是一致，除了页码需要跟着页面变动而改变。在itext7 提供了事件出来的方式。代码如下    

pdfDoc.addEventHandler(type,IEventHandler);

    参数：type   ：  事件的类型，有四种分别是 PdfDocumentEvent.END_PAGE ； PdfDocumentEvent.START_PAGE； PdfDocumentEvent.INSERT_PAGE； PdfDocumentEvent.REMOVE_PAGE。

                               看名称就是知道分别代表都是页面完成，开始，插入，移除时触发事件

              IEventHandler  ： 触发的事件具体代码，需要自己编写一个类，并实现接口IEventHandler

二、具体代码

     1、实现接口IEventHandler的类  DemoHeaderFooterHandler.java      

public class DemoHeaderFooterHandler implements IEventHandler {

	private final String imgLogo;
	private final PdfFont font;

	public DemoHeaderFooterHandler(final String imgLogo, final PdfFont font) {
		this.imgLogo = imgLogo;
		this.font = font;
	}

	@Override
	public void handleEvent(final Event event) {
		try {
			final PdfDocumentEvent docEvent = (PdfDocumentEvent) event;
			final PdfDocument pdfDoc = docEvent.getDocument();
			final Document doc = new Document(pdfDoc);
			final PdfPage page = docEvent.getPage();
			final int pageNumber = pdfDoc.getPageNumber(page);
			final Rectangle pageSize = page.getPageSize();
			final float pdfWidth = pageSize.getWidth();
			final float pdfHeight = pageSize.getHeight();
			final PdfCanvas pdfCanvas = new PdfCanvas(page.newContentStreamBefore(), page.getResources(), pdfDoc);
			final Color lineColor = new DeviceRgb(57, 123, 198);
			pdfCanvas.setLineWidth(1.5f).setStrokeColor(lineColor);
			final float tableWidth = pdfWidth - doc.getRightMargin() - doc.getLeftMargin();
			// 页眉
			final float x0 = doc.getRightMargin(), y0 = pdfHeight - doc.getTopMargin();
			pdfCanvas.moveTo(x0, y0).lineTo(pdfWidth - doc.getRightMargin(), y0).stroke();
			final Table headerTable = new Table(2);
			headerTable.setHeight(30);
			headerTable.setFixedLayout();
			headerTable.setWidth(tableWidth);
			headerTable.setHorizontalAlignment(HorizontalAlignment.CENTER);

			final Paragraph pageNameParagraph = new Paragraph();
			// realnameParagraph.setFixedLeading(4f);
			pageNameParagraph.setVerticalAlignment(VerticalAlignment.BOTTOM);
			pageNameParagraph.add("页面名称");

			final Cell pageNameCell = new Cell();
			pageNameCell.setBorder(Border.NO_BORDER);
			pageNameCell.add(pageNameParagraph);
			pageNameCell.setFont(this.font);
			pageNameCell.setFontSize(12f);
			pageNameCell.setFontColor(lineColor);
			pageNameCell.setVerticalAlignment(VerticalAlignment.BOTTOM);
			headerTable.addCell(pageNameCell);

			final Paragraph realnameParagraph = new Paragraph();
			// realnameParagraph.setFixedLeading(4f);
			realnameParagraph.setVerticalAlignment(VerticalAlignment.BOTTOM);
			realnameParagraph.add(new Tab()).addTabStops(new TabStop(1000, TabAlignment.RIGHT));
			realnameParagraph.add("半路凉亭");
			final Cell realnameCell = new Cell();
			realnameCell.setBorder(Border.NO_BORDER);
			realnameCell.add(realnameParagraph);
			realnameCell.setFont(this.font);
			realnameCell.setFontSize(12f);
			realnameCell.setFontColor(lineColor);
			realnameCell.setVerticalAlignment(VerticalAlignment.BOTTOM);
			headerTable.addCell(realnameCell);
			headerTable.setFixedPosition(doc.getLeftMargin(), pdfHeight - doc.getTopMargin(), tableWidth);
			doc.add(headerTable);

			// 页脚
			pdfCanvas.moveTo(x0, doc.getBottomMargin()).lineTo(pdfWidth - doc.getRightMargin(), doc.getBottomMargin())
					.stroke();

			final Table table = new Table(2);
			table.setHeight(40);
			table.setFixedLayout();
			table.setWidth(tableWidth);
			table.setHorizontalAlignment(HorizontalAlignment.CENTER);

			final Cell imgCell = new Cell();
			imgCell.setBorder(Border.NO_BORDER);
			imgCell.add(this.getLogoImage());
			imgCell.setVerticalAlignment(VerticalAlignment.TOP);
			table.addCell(imgCell);
			final String pageNo = String.format("%d", pageNumber);
			final Paragraph pageNoParagraph = new Paragraph();
			pageNoParagraph.setFontColor(new DeviceRgb(166, 166, 166));
			pageNoParagraph.setFontSize(12f);
			pageNoParagraph.add(new Tab()).addTabStops(new TabStop(1000, TabAlignment.RIGHT));
			pageNoParagraph.add(pageNo);
			table.addCell(new Cell().add(pageNoParagraph).setBorder(Border.NO_BORDER));
			table.setFixedPosition(doc.getLeftMargin(), doc.getBottomMargin() - table.getHeight().getValue(),
					tableWidth);
			doc.add(table);
			System.out.println("***" + table.getHeight());

		} catch (final Exception e) {
			e.printStackTrace();
			throw new NormStarRuntimeException("页脚异常" + e.getMessage());
		}
	}

	private Image getLogoImage() {
		Image image;
		try {
			image = new Image(ImageDataFactory.create(this.imgLogo));
			image.scaleToFit(75, 100);
		} catch (final MalformedURLException e) {
			final String errorMessage = "logo图片";
			throw new NormStarRuntimeException(errorMessage, e);
		}
		return image;
	}

}

    2、生成文档的代码 

    private final String fileImg = "D:/itext-pdf/logo.png";
	public PdfFont getSongTiFont() throws IOException {
		return PdfFontFactory.createFont("STSong-Light", "UniGB-UCS2-H", false);
	}

	public PdfFont getHeiTiFont() throws IOException {
		return PdfFontFactory.createFont("D:/itext-pdf/font/heiti.TTF", PdfEncodings.IDENTITY_H,
				false);
	}

	/**
	 * 页眉页脚
	 *
	 * @author 
	 * @date 2021年3月29日
	 */
	@Test
	public void testHeaderFooter() {
		final File file = new File("D:/itext-pdf/001.pdf");
		Document doc = null;
		try {
			final PdfFont font = this.getSongTiFont();
			final PdfWriter writer = new PdfWriter(file);
			final PdfDocument pdfDoc = new PdfDocument(writer);
			doc = new Document(pdfDoc);
			final Image img = new Image(ImageDataFactory.create(this.fileImg));
			img.setHeight(new UnitValue(UnitValue.POINT, 35f));
			img.setWidth(new UnitValue(UnitValue.POINT, 100f));
			doc.setMargins(50, 60, 50, 60);
			pdfDoc.addEventHandler(PdfDocumentEvent.END_PAGE,
					new DemoHeaderFooterHandler(this.fileImg, this.getHeiTiFont()));
			pdfDoc.addNewPage();

			final int number = pdfDoc.getNumberOfPages();
			final float pdfWidth = pdfDoc.getPage(number).getPageSize().getWidth();
			final float pdfHeight = pdfDoc.getPage(number).getPageSize().getHeight();

			final Paragraph paragraph = new Paragraph("你好 itext-pdf");
			paragraph.add("第" + number + "页");
			paragraph.add("宽：" + pdfWidth + " 高：" + pdfHeight); // 宽：595.0 高：842.0
			paragraph.setFont(font);
			paragraph.add(img);
			doc.add(paragraph);
			// PdfContentByte cb = writer.getDirectContent();
			final PdfOutline root = pdfDoc.getOutlines(true);
			final String title = String.format("Numbers from %s to %s", 1, 10);
			final Text c = new Text(title);
			//final TOCTextRenderer renderer = new TOCTextRenderer(root, c);
			//c.setNextRenderer(renderer);
			doc.add(new Paragraph(c));
            pdfDoc.addNewPage();
			System.out.println("***" + root.getTitle());
		} catch (final Exception e) {
			e.printStackTrace();
			final String errorMessage = "异常";
			throw new NormStarRuntimeException(errorMessage, e);
		} finally {
			if (doc != null) {
				doc.close();
			}
		}
	}

     注意：

        1.中文字体问题  

                 页尾页脚中如果有中文字体，则必须使用外部嵌入的字体，如我这里嵌入的黑体，使用默认的宋体，则会报错

        2.表格绝对坐标定位

            setFixedPosition(); 使用这个方法写入表格时，是以表格的左下角为坐标原点定位的。