PDFBOX - 使用easytable在所有页面中添加标题 [英] PDFBOX - header in all pages using easytable

问题描述

我使用 pdfbox 和 easytable

警告:这是一个概念证明，我只测试了来自 TwoPagesTableTest 的表格生成代码.对于生产代码，您应该应用进一步的测试.

I am using pdfbox and easytable https://github.com/vandeseer/easytable for creating dynamic pages which works great. But I do want header to be added in alL pages. I faced/tried below things.

1) Tablebuilder is created before writing rows so we can create a perfect tablebuilder since rows are dynamic.

2) Tried to insert header in middle while creating tablebuilder which again is not perfect since TableDrawer makes the rows to suffice according to row height

Any idea/help would be appreciated.

Need output similar to this project - https://github.com/eduardohl/Paginated-PDFBox-Table-Sample . only problem here being the content is not dynamic like easytable.

解决方案

This answer had been written at an earlier time when easytable had not yet supported repeating table headers. Meanwhile it does, see the answer by philonous, the easytable author.

easytable does not support repeating table headers or footers. Not yet I should say because this feature actually is easy to implement.

It is difficult, though, to implement on top of easytable because that library (like many others) suffers from excessive data hiding: many interesting member variables and methods are private, so extending the classes is not a viable option.

But what you can do is handle the header rows as a separate table which you draw again and again! The downside is a bit of duplicity of settings.

In case of the test code TwoPagesTableTest you referred to, it can be changed like this:

final Table.TableBuilder tableHeaderBuilder = Table.builder()
        .addColumnOfWidth(200)
        .addColumnOfWidth(200);

CellText dummyHeaderCell = CellText.builder()
        .text("Header dummy")
        .backgroundColor(Color.BLUE)
        .textColor(Color.WHITE)
        .borderWidth(1F)
        .build();

tableHeaderBuilder.addRow(
        Row.builder()
                .add(dummyHeaderCell)
                .add(dummyHeaderCell)
                .build());

Table tableHeader = tableHeaderBuilder.build();

final Table.TableBuilder tableBuilder = Table.builder()
        .addColumnOfWidth(200)
        .addColumnOfWidth(200);

CellText dummyCell = CellText.builder()
        .text("dummy")
        .borderWidth(1F)
        .build();

for (int i = 0; i < 50; i++) {
    tableBuilder.addRow(
            Row.builder()
                    .add(dummyCell)
                    .add(dummyCell)
                    .build());
}

TableDrawer drawer = TableDrawer.builder()
        .table(tableBuilder.build())
        .startX(50)
        .endY(50F) // note: if not set, table is drawn over the end of the page
        .build();

final PDDocument document = new PDDocument();

float startY = 100F;

do {
    TableDrawer headerDrawer = TableDrawer.builder()
            .table(tableHeader)
            .startX(50)
            .build();

    PDPage page = new PDPage(PDRectangle.A4);
    document.addPage(page);
    try (PDPageContentStream contentStream = new PDPageContentStream(document, page)) {
        headerDrawer.startY(startY);
        headerDrawer.contentStream(contentStream).draw();
        drawer.startY(startY - tableHeader.getHeight());
        drawer.contentStream(contentStream).draw();
    }

    startY = page.getMediaBox().getHeight() - 50;
} while (!drawer.isFinished());

document.save("twoPageTable-repeatingHeader.pdf");
document.close();

(RepeatingTableHeaders test createTwoPageTableRepeatingHeader)

As you see, the code first creates a separate Table tableHeader containing only the header row. This table then is added first on each page and a part of the body rows table is added thereafter.

The result: table headers on each page...

A word of warning: This is a proof of concept, I have only tested with the table generation code from TwoPagesTableTest. For production code you should apply further tests.

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