使用iText从pdf文件中提取一个页面 [英] extracting one page from pdf file using iText

问题描述

我想使用itext库从java servlet中返回pdf文件中的一页（以减小文件大小下载）。
使用此代码

  try {
 PdfReader reader = new PdfReader（input）; 
 Document document = new Document（reader.getPageSizeWithRotation（page_number））; 
 
 
 PdfSmartCopy copy1 = new PdfSmartCopy（document，response.getOutputStream（））; 
 copy1.setFullCompression（）; 
 document.open（）; 
 
 copy1.addPage（copy1.getImportedPage（reader，page_i））; 
 copy1.freeReader（reader）; 
 reader.close（）; 
 
 document.close（）; 
 
} catch（DocumentException e）{
 e.printStackTrace（）; 
} 
  

这段代码返回页面，但文件大小很大，有时候等于原始文件大小，即使它只是一个页面。

解决方案

我从您的存储库中下载了一个文件：腹部。 pdf

然后我使用下面的代码来破译PDF：

  public static void main（String [] args）throws DocumentException，IOException {
 PdfReader reader = new PdfReader（resources / Abdomen.pdf）; 
 int n = reader.getNumberOfPages（）; 
 reader.close（）; 
字符串路径; 
 PdfStamper压模; 
 for（int i = 1; i <= n; i ++）{
 reader = new PdfReader（resources / abdomen.pdf）; 
 reader.selectPages（String.valueOf（i））; 
 path = String.format（results / abdomen / p-％s.pdf，i）; 
 stamper = new PdfStamper（reader，new FileOutputStream（path））; 
 stamper.close（）; 
 reader.close（）; 
} 
} 
  

对于突发意味着在分开的页面中进行拆分。尽管原始文件Abdomen.pdf是72,570KB（约70.8MB），但单独的页面要小得多： b
$ b

我无法重现您描述的问题。

I want to return one page from pdf files from java servlet (to reduce file size download), using itext library. using this code

     try {
        PdfReader reader = new PdfReader(input);
        Document document = new Document(reader.getPageSizeWithRotation(page_number) );


        PdfSmartCopy copy1 = new PdfSmartCopy(document, response.getOutputStream());
        copy1.setFullCompression();
        document.open();

        copy1.addPage(copy1.getImportedPage(reader, page_i) );
        copy1.freeReader(reader);
        reader.close();

        document.close();

    } catch (DocumentException e) {
        e.printStackTrace();
    }

this code returns the page, but the file size is large and some times equals the original file size, even it is just a one page.

解决方案

I have downloaded a single file from your repository: Abdomen.pdf

I have then used the following code to "burst" that PDF:

public static void main(String[] args) throws DocumentException, IOException {
    PdfReader reader = new PdfReader("resources/Abdomen.pdf");
    int n = reader.getNumberOfPages();
    reader.close();
    String path;
    PdfStamper stamper;
    for (int i = 1; i <= n; i++) {
        reader = new PdfReader("resources/abdomen.pdf");
        reader.selectPages(String.valueOf(i));
        path = String.format("results/abdomen/p-%s.pdf", i);
        stamper = new PdfStamper(reader,new FileOutputStream(path));
        stamper.close();
        reader.close();
    }
}

To "burst" means to split in separate pages. While the original file Abdomen.pdf is 72,570 KB (about 70.8 MB), the separate pages are much smaller:

I can not reproduce the problem you describe.

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