C#使用iTextSharp将PDF转成文本的方法

using System;
using System.IO; 
using iTextSharp.text;
using iTextSharp.text.pdf;
using iTextSharp.text.pdf.parser;
public class ParsingPDF {
  static string PDF;
  static string TEXT2;
  /**
   * Parses the PDF using PRTokeniser
   * @param src the path to the original PDF file
   * @param dest the path to the resulting text file
   */
  public void parsePdf(String src, String dest)
  {
    PdfReader reader = new PdfReader(src);
    StreamWriter output = new StreamWriter(new FileStream(dest, FileMode.Create));
    int pageCount = reader.NumberOfPages;
    for (int pg = 1; pg <= pageCount; pg++)
    {
      // we can inspect the syntax of the imported page
      byte[] streamBytes = reader.GetPageContent(pg);
      PRTokeniser tokenizer = new PRTokeniser(streamBytes);
      while (tokenizer.NextToken())
      {
        if (tokenizer.TokenType == PRTokeniser.TokType.STRING)
        {
          output.WriteLine(tokenizer.StringValue);
        }
      }
    }
    output.Flush();
    output.Close();
  }
  /**
   * Main method.
   */
  static void Main(string[] args)
  {
    if (args.Length < 1 || args.Length > 2)
    {
      Console.WriteLine("USAGE: ParsePDF infile.pdf <outfile.txt>");
      return;
    }
    else if (args.Length == 1)
    {
      PDF = args[0];
      TEXT2 = Path.GetFileNameWithoutExtension(PDF) + ".txt";
    }
    else
    {
      PDF = args[0];
      TEXT2 = args[1];
    }
    try
    {
      DateTime t1 = DateTime.Now;
      ParsingPDF example = new ParsingPDF();
      example.parsePdf(PDF, TEXT2);
      DateTime t2 = DateTime.Now;
      TimeSpan ts = t2 - t1;
      Console.WriteLine("Parsing completed in {0:0.00} seconds.", ts.TotalSeconds);
    }
    catch (Exception ex)
    {
      Console.WriteLine("ERROR: " + ex.Message);
    }
  } // class
  public class MyTextRenderListener : IRenderListener
  {
    /** The print writer to which the information will be written. */
    protected StreamWriter output;
    /**
     * Creates a RenderListener that will look for text.
     */
    public MyTextRenderListener(StreamWriter output)
    {
      this.output = output;
    }
    public void BeginTextBlock()
    {
      output.Write("<");
    }
    public void EndTextBlock()
    {
      output.WriteLine(">");
    }
    public void RenderImage(ImageRenderInfo renderInfo)
    {
    }
    public void RenderText(TextRenderInfo renderInfo)
    {
      output.Write("<");
      output.Write(renderInfo.GetText());
      output.Write(">");
    }
  } // class
} // namespace