iText GetTextFromPage 返回每个页面开头的文本

Question

我有这个简单的作品。问题很奇怪 - 在每次迭代中，阅读器都会返回自 pdf 文档开头以来的整个文本。也许这很简单，但我看不到。

...
PdfReader reader = new PdfReader ( path );
PdfReaderContentParser parser = new PdfReaderContentParser ( reader );
...
public void Read(int start, int end)
{
    ITextExtractionStrategy strategy = new SimpleTextExtractionStrategy();

    StringBuilder sb = new StringBuilder();

    for (int page = start; page < end; page++)
    {
        try
        {
            sb.Append(PdfTextExtractor.GetTextFromPage(reader, page, strategy));
        }
        catch (Exception ex)
        {
            throw new PdfException(ex.Message, ex.InnerException);
        }

        var p = new Page { Number = page, Content = sb.ToString()};
        sb.Clear();
        PageParsed?.Invoke(this, new PdfEventArgs<Page>(p));
    }
    FileParsed?.Invoke(this, new PdfEventArgs<string>(string.IsNullOrEmpty(Name) ? "File parsed" : Name));
}

Answer 1

对象strategy保留状态，因此您必须在循环内移动对象实例，如下所示：

StringBuilder sb = new StringBuilder();

for (int page = start; page < end; page++)
{
    ITextExtractionStrategy strategy = new SimpleTextExtractionStrategy();
    try
    {
        sb.Append(PdfTextExtractor.GetTextFromPage(reader, page, strategy));
    }
    catch (Exception ex)
    {
        throw new PdfException(ex.Message, ex.InnerException);
    }

    var p = new Page { Number = page, Content = sb.ToString()};
    sb.Clear();
    PageParsed?.Invoke(this, new PdfEventArgs<Page>(p));
}

这将解决您的问题。