C#编程读取文档Doc，Docx，Pdf的内容

Doc文档：Microsoft Word 14.0 Object Library (GAC对象，调用前需要安装word。安装的word版本不同，COM的版本号也会不同)
Docx文档：Microsoft Word 14.0 Object Library (GAC对象，调用前需要安装word。安装的word版本不同，COM的版本号也会不同)
Pdf文档：PDFBox

/*
     作者：GhostBear
 *   博客地址：Http://blog.csdn.net/ghostbear
 */
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Text.RegularExpressions;

using org.pdfbox.pdmodel;
using org.pdfbox.util;

using Microsoft.Office.Interop.Word;


namespace TestPdfReader
{
    class Program
    {
        static void Main(string[] args)
        {


            //PDF
            PDDocument doc = PDDocument.load(@"C:resume.pdf");
            PDFTextStripper pdfStripper = new PDFTextStripper();
            string text = pdfStripper.getText(doc);
            string result = text.Replace('t',' ').Replace('n',' ').Replace('r',' ').Replace(" ","");
            Console.WriteLine(result);


            //Doc,Docx
            object docPath = @"C:resume.doc";
            object docxPath = @"C:resume.docx";
            object missing=System.Reflection.Missing.Value;
            object readOnly=true;

            Application wordApp;
            wordApp = new Application();

            Document wordDoc = wordApp.Documents.Open(ref docPath,ref missing,ref readOnly,ref missing);
            string text2 = FilterString(wordDoc.Content.Text);

            wordDoc.Close(ref missing,ref missing);
            wordApp.Quit(ref missing,ref missing);
            Console.WriteLine(text2);


            Console.Read();
            
        }

        private static string FilterString(string input)
        {
            return Regex.Replace(input,@"(a|t|n|s+)","");
           
        }
    }
}