使用ColumnText会导致“文档没有页面”例外 [英] Using ColumnText results in "The document has no pages" exception

问题描述

我想将文字换成图像下方（或左侧或右侧）的矩形，如下所示：

I want to wrap text in a rect which is below (or left or right) of a image as below :

请参阅链接： http://upanh.in/SLk/

我使用ColumnText在我的代码中包装文本：

I use ColumnText for wrapping text in my code:

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    response.setContentType("application/pdf");
    try {
        // step 1
        Document document = new Document(PageSize.A4.rotate());
        // step 2
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        PdfWriter writer = PdfWriter.getInstance(document, baos);
        // step 3
        document.open();
        // step 4
        ColumnText column = new ColumnText(writer.getDirectContent());
        column.setSimpleColumn(new Phrase("text is very long ..."), 10, 10, 20, 20, 18, Element.ALIGN_CENTER);
        column.go();

        // step 5
        document.close();
        ServletOutputStream os = response.getOutputStream();
        baos.writeTo(os);
        os.flush();
        os.close();
    } catch (DocumentException e) {
        throw new IOException(e.getMessage());
    }
}

结果：

ExceptionConverter：java.io.IOException：该文档没有页面。

ExceptionConverter: java.io.IOException: The document has no pages.

您对此有何建议？

问题2

I尝试使用下面的代码在rect中显示文本（中间和中间）但不成功。文本只是矩形的中心。

I try to display text (center and middle) in the rect with below code but it wasn't success. The text was only center in the rect.

ColumnText column = new ColumnText(writer.getDirectContent());
column.setSimpleColumn(RectImg1[0], RectImg1[1], RectImg1[0] + squareHeight, RectImg1[1] + squareHeight
                        * 1 / 4);
Paragraph p = new Paragraph(imgr.getText(), fontH);
p.setAlignment(Element.ALIGN_CENTER | Element.ALIGN_MIDDLE);
p.setLeading(18);
column.addElement(p);
column.go();

我的错误在哪里？

推荐答案

我已经编辑了你的问题的标题，因为它有误导性：你遇到的例外情况也会发生在一个独立的应用程序中。您在Servlet中使用代码这一事实无关紧要。

I have edited the title of your question because it was misleading: the exception you encounter will occur in a standalone application too. The fact that you are using the code in a Servlet is irrelevant.

我看到您有以下行：

column.go();

你没有使用这样的东西：

You did not use something like this:

int status = column.go();

如果你这样做，并且你检查了状态，你会注意到列对象仍然包含一些文字。

If you did, and if you examined status, you would have noticed that the column object still contained some text.

什么文字？ 所有文字。

此行中存在严重错误：

column.setSimpleColumn(new Phrase("text is very long ..."), 10, 10, 20, 20, 18, Element.ALIGN_CENTER);

您正在尝试添加文本文字很长... 进入一个带有以下坐标的矩形：

You are trying to add the text "text is very long ..." into a rectangle with the following coordinates:

float llx = 10;
float lly = 10;
float urx = 20;
float ury = 20;

您没有定义字体，因此字体是Helvetica，字体大小为12pt，您定义了18pt的领先优势。

You didn't define a font, so the font is Helvetica with font size 12pt and you defined a leading of 18pt.

这意味着你试图将12pt高的文本与额外的6pt相匹配，以便进入一个10×10 pt的正方形。当然你明白这不起作用！

This means that you are trying to fit text that is 12pt high with an extra 6pt for the leading into a square that measures 10 by 10 pt. Surely you understand that this can't work!

因此，没有任何内容添加到PDF而不是显示空白页面，iText会抛出异常说：那里没有页面！ 您没有在文档中添加任何内容！

As a result, nothing is added to the PDF and rather than showing an empty page, iText throws an exception saying: there are no pages! You didn't add any content to the document!

您可以解决此问题，例如将错误的行更改为以下内容：

You can fix this, for instance by changing the incorrect line into something like this:

column.setSimpleColumn(new Phrase("text is very long ..."), 36, 36, 559, 806, 18, Element.ALIGN_CENTER);

另一种选择是：

column.setSimpleColumn(rect);
column.addElement(paragraph);

在这两行 rect 是 Rectangle 对象。前导和对齐将在段落对象的级别定义（在这种情况下，您不使用短语）。

In these two lines rect is a Rectangle object. The leading and the alignment are to be defined at the level of the Paragraph object (in this case, you don't use a Phrase).

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