当我使用iText从PDF文件中提取文本时，我正在从以前的页面中获取值 [英] When I extract text from a PDF file using iText I am getting values from previous pages

问题描述

我正在尝试从多页PDF文件中的每一页的特定位置提取文本块.

I am trying to extract a block of text from a specific location from each page in a multiple page PDF file.

我知道了文本的位置，并且能够在第一页上正确地提取文本. 但是，在第一页之后的页面上，提取的文本似乎正在堆积.

I have the location of the text, and I am able to extract it correctly on the first page. However on the pages after the first page, the text extracted seems to be accumulating.

例如，如果页面1上的文本值为"A"，则页面2为"B".而第3页为"C"，那么我通过FOR循环在每次迭代的输出字符串中都会收到以下值:

For example if the text value on page 1 is "A", page 2 is "B" and Page 3 is "C" then I am receiving the following values in my output string for each iteration through my FOR loop:

循环1:输出= A

Loop1 : output = A

回路2:输出= B A

Loop2 : output = B A

循环3:输出= C B A

Loop3 : output = C B A

我正在用C#编写的项目中使用iTextSharp.

I am using iTextSharp in my project, written in C#.

任何帮助将不胜感激.

var reader = new PdfReader(foregroundFile);

RectangleJ customerIdRectangle = new RectangleJ(0, 495, 108, 27);
RenderFilter[] filters = new RenderFilter[1];
LocationTextExtractionStrategy regionFilter = new LocationTextExtractionStrategy();
filters[0] = new RegionTextRenderFilter(customerIdRectangle);
FilteredTextRenderListener strategy = new FilteredTextRenderListener(regionFilter, filters);

for (int i = 1; i <= reader.NumberOfPages; i++)
{
    string output = "";
    output = PdfTextExtractor.GetTextFromPage(reader, i, strategy);
    Console.WriteLine(output);
}

推荐答案

请像这样修改您的代码:

Please adapt your code like this:

var reader = new PdfReader(foregroundFile);

RectangleJ customerIdRectangle = new RectangleJ(0, 495, 108, 27);

for (int i = 1; i <= reader.NumberOfPages; i++)
{
    RenderFilter[] filters = new RenderFilter[1];
    LocationTextExtractionStrategy regionFilter = new LocationTextExtractionStrategy();
    filters[0] = new RegionTextRenderFilter(customerIdRectangle);
    FilteredTextRenderListener strategy = new FilteredTextRenderListener(regionFilter, filters);
    string output = "";
    output = PdfTextExtractor.GetTextFromPage(reader, i, strategy);
    Console.WriteLine(output);
}

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