java 从pdf中获取页面并将其保存为带有itext的图像文件
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Get a page from pdf and save it to an image file with itext
提问by Freewind
There is a pdf file, and I want to import the 2nd page as an image and save it to a jpeg file. Is it possible and how to do it?
有一个pdf文件，我想将第二页作为图像导入并将其保存为jpeg文件。是否有可能以及如何做到？
This is the code how I import a page:
这是我如何导入页面的代码：
Document document = new Document();
File file = File.createTempFile("", "");
PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(file));
document.open();
final int backPage = 2;
PdfReader reader = new PdfReader(pdf.getAbsolutePath());
PdfImportedPage importedPage = writer.getImportedPage(reader, backPage);
com.lowagie.text.Image image = com.lowagie.text.Image.getInstance(importedPage);
Now I get an imageinstance, but I don't know how to write it to a jpeg file.
现在我得到了一个image实例，但我不知道如何将它写入 jpeg 文件。
采纳答案by Andrea Ligios
Appearently (according to 1T3XT BVBA), you can only save an iText Image from a PDF page, not a raster image. You can store it everywhere, if you will use later to put it in another PDF page... otherwise, you'll have to use a tool like JPedal:
显然（根据1T3XT BVBA），您只能从 PDF 页面保存 iText 图像，而不是光栅图像。你可以把它存储在任何地方，如果你以后要用它把它放在另一个 PDF 页面中......否则，你将不得不使用像 JPedal 这样的工具：
http://www.idrsolutions.com/convert-pdf-to-images/
http://www.idrsolutions.com/convert-pdf-to-images/
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EDIT: maybe PDFBox can do it for you too!:
编辑：也许 PDFBox 也可以为您做！：
http://pdfbox.apache.org/commandlineutilities/PDFToImage.html
http://pdfbox.apache.org/commandlineutilities/PDFToImage.html
http://gal-levinsky.blogspot.it/2011/11/convert-pdf-to-image-via-pdfbox.html
http://gal-levinsky.blogspot.it/2011/11/convert-pdf-to-image-via-pdfbox.html
回答by mkl
Image.getInstance(importedPage) does not (as one might assume) render the denoted page as some bitmap but merely creates a wrapper object to make the imported page easier to add to another PDF.
Image.getInstance(importedPage) 不会（正如人们可能认为的那样）将表示的页面呈现为某个位图，而只是创建一个包装对象，使导入的页面更容易添加到另一个 PDF。
iText is not a PDF rendering tool, especially not the old com.lowagie variant. You may want to look at different products, e.g. JPedal.
iText 不是 PDF 渲染工具，尤其不是旧的 com.lowagie 变体。您可能想查看不同的产品，例如JPedal。
