如何使用Apache pdfbox在PDF中生成多行

Question

我正在使用Pdfbox使用Java生成PDF文件。问题是，当我在文档中添加长文本内容时，它没有正确显示。只显示它的一部分。这也是单行的。

我希望文本在多行。

下面给出了我的代码：

PDPageContentStream pdfContent=new PDPageContentStream(pdfDocument, pdfPage, true, true);

pdfContent.beginText();
pdfContent.setFont(pdfFont, 11);
pdfContent.moveTextPositionByAmount(30,750);            
pdfContent.drawString("I am trying to create a PDF file with a lot of text contents in the document. I am using PDFBox");
pdfContent.endText();

我的输出：

Answer 1

添加到Mark的答案中，您可能想知道在哪里拆分长字符串。您可以使用pdfont方法getStringWidth。

将所有内容放在一起，您会得到如下内容（根据PDFBox版本的不同有一些小的差异）：

PDDocument doc = null;
try
{
    doc = new PDDocument();
    PDPage page = new PDPage();
    doc.addPage(page);
    PDPageContentStream contentStream = new PDPageContentStream(doc, page);

    PDFont pdfFont = PDType1Font.HELVETICA;
    float fontSize = 25;
    float leading = 1.5f * fontSize;

    PDRectangle mediabox = page.findMediaBox();
    float margin = 72;
    float width = mediabox.getWidth() - 2*margin;
    float startX = mediabox.getLowerLeftX() + margin;
    float startY = mediabox.getUpperRightY() - margin;

    String text = "I am trying to create a PDF file with a lot of text contents in the document. I am using PDFBox"; 
    List<String> lines = new ArrayList<String>();
    int lastSpace = -1;
    while (text.length() > 0)
    {
        int spaceIndex = text.indexOf(' ', lastSpace + 1);
        if (spaceIndex < 0)
            spaceIndex = text.length();
        String subString = text.substring(0, spaceIndex);
        float size = fontSize * pdfFont.getStringWidth(subString) / 1000;
        System.out.printf("'%s' - %f of %f\n", subString, size, width);
        if (size > width)
        {
            if (lastSpace < 0)
                lastSpace = spaceIndex;
            subString = text.substring(0, lastSpace);
            lines.add(subString);
            text = text.substring(lastSpace).trim();
            System.out.printf("'%s' is line\n", subString);
            lastSpace = -1;
        }
        else if (spaceIndex == text.length())
        {
            lines.add(text);
            System.out.printf("'%s' is line\n", text);
            text = "";
        }
        else
        {
            lastSpace = spaceIndex;
        }
    }
        
    contentStream.beginText();
    contentStream.setFont(pdfFont, fontSize);
    contentStream.moveTextPositionByAmount(startX, startY);            
    for (String line: lines)
    {
        contentStream.drawString(line);
        contentStream.moveTextPositionByAmount(0, -leading);
    }
    contentStream.endText(); 
    contentStream.close();

    doc.save("break-long-string.pdf");
}
finally
{
    if (doc != null)
    {
        doc.close();
    }
}

(breaklongstring.java testtestbreakstringfor PDFBox 1.8.x)

PDDocument doc = null;
try
{
    doc = new PDDocument();
    PDPage page = new PDPage();
    doc.addPage(page);
    PDPageContentStream contentStream = new PDPageContentStream(doc, page);

    PDFont pdfFont = PDType1Font.HELVETICA;
    float fontSize = 25;
    float leading = 1.5f * fontSize;

    PDRectangle mediabox = page.getMediaBox();
    float margin = 72;
    float width = mediabox.getWidth() - 2*margin;
    float startX = mediabox.getLowerLeftX() + margin;
    float startY = mediabox.getUpperRightY() - margin;

    String text = "I am trying to create a PDF file with a lot of text contents in the document. I am using PDFBox"; 
    List<String> lines = new ArrayList<String>();
    int lastSpace = -1;
    while (text.length() > 0)
    {
        int spaceIndex = text.indexOf(' ', lastSpace + 1);
        if (spaceIndex < 0)
            spaceIndex = text.length();
        String subString = text.substring(0, spaceIndex);
        float size = fontSize * pdfFont.getStringWidth(subString) / 1000;
        System.out.printf("'%s' - %f of %f\n", subString, size, width);
        if (size > width)
        {
            if (lastSpace < 0)
                lastSpace = spaceIndex;
            subString = text.substring(0, lastSpace);
            lines.add(subString);
            text = text.substring(lastSpace).trim();
            System.out.printf("'%s' is line\n", subString);
            lastSpace = -1;
        }
        else if (spaceIndex == text.length())
        {
            lines.add(text);
            System.out.printf("'%s' is line\n", text);
            text = "";
        }
        else
        {
            lastSpace = spaceIndex;
        }
    }

    contentStream.beginText();
    contentStream.setFont(pdfFont, fontSize);
    contentStream.newLineAtOffset(startX, startY);
    for (String line: lines)
    {
        contentStream.showText(line);
        contentStream.newLineAtOffset(0, -leading);
    }
    contentStream.endText(); 
    contentStream.close();

    doc.save(new File(RESULT_FOLDER, "break-long-string.pdf"));
}
finally
{
    if (doc != null)
    {
        doc.close();
    }
}

(breaklongstring.java testtestbreakstringfor PDFBox 2.0.x)

这看起来不出所料。

当然，还有许多改进要做，但这应该说明如何做到这一点。

String text = "I am trying to create a PDF file with a lot of text contents in the document. I am using PDFBox"; 

String textNL = "I am trying to create a PDF file with a lot of text contents in the document. I am using PDFBox.\nFurthermore, I have added some newline characters to the string at which lines also shall be broken.\nIt should work alright like this...";

您可以简单地替换

String text = "I am trying to create a PDF file with a lot of text contents in the document. I am using PDFBox"; 
List<String> lines = new ArrayList<String>();
int lastSpace = -1;
while (text.length() > 0)
{
    [...]
}

在上面的解决方案中

String textNL = "I am trying to create a PDF file with a lot of text contents in the document. I am using PDFBox.\nFurthermore, I have added some newline characters to the string at which lines also shall be broken.\nIt should work alright like this..."; 
List<String> lines = new ArrayList<String>();
for (String text : textNL.split("\n"))
{
    int lastSpace = -1;
    while (text.length() > 0)
    {
        [...]
    }
}

（来自breaklongstring.java testtestbreakstringnl)