在.Net中读PDF文档
有没有一个开源的库，帮助我阅读/parsing.Net / C＃中的PDF文档？
iTextSharp是最好的select。 用它为lucene.Net制作一个蜘蛛，以便抓取PDF。
using System; using System.IO; using iTextSharp.text.pdf; using System.Text.RegularExpressions; namespace Spider.Utils { /// <summary> /// Parses a PDF file and extracts the text from it. /// </summary> public class PDFParser { /// BT = Beginning of a text object operator /// ET = End of a text object operator /// Td move to the start of next line /// 5 Ts = superscript /// -5 Ts = subscript #region Fields #region _numberOfCharsToKeep /// <summary> /// The number of characters to keep, when extracting text. /// </summary> private static int _numberOfCharsToKeep = 15; #endregion #endregion #region ExtractText /// <summary> /// Extracts a text from a PDF file. /// </summary> /// <param name="inFileName">the full path to the pdf file.</param> /// <param name="outFileName">the output file name.</param> /// <returns>the extracted text</returns> public bool ExtractText(string inFileName, string outFileName) { StreamWriter outFile = null; try { // Create a reader for the given PDF file PdfReader reader = new PdfReader(inFileName); //outFile = File.CreateText(outFileName); outFile = new StreamWriter(outFileName, false, System.Text.Encoding.UTF8); Console.Write("Processing: "); int totalLen = 68; float charUnit = ((float)totalLen) / (float)reader.NumberOfPages; int totalWritten = 0; float curUnit = 0; for (int page = 1; page <= reader.NumberOfPages; page++) { outFile.Write(ExtractTextFromPDFBytes(reader.GetPageContent(page)) + " "); // Write the progress. if (charUnit >= 1.0f) { for (int i = 0; i < (int)charUnit; i++) { Console.Write("#"); totalWritten++; } } else { curUnit += charUnit; if (curUnit >= 1.0f) { for (int i = 0; i < (int)curUnit; i++) { Console.Write("#"); totalWritten++; } curUnit = 0; } } } if (totalWritten < totalLen) { for (int i = 0; i < (totalLen - totalWritten); i++) { Console.Write("#"); } } return true; } catch { return false; } finally { if (outFile != null) outFile.Close(); } } #endregion #region ExtractTextFromPDFBytes /// <summary> /// This method processes an uncompressed Adobe (text) object /// and extracts text. /// </summary> /// <param name="input">uncompressed</param> /// <returns></returns> public string ExtractTextFromPDFBytes(byte[] input) { if (input == null || input.Length == 0) return ""; try { string resultString = ""; // Flag showing if we are we currently inside a text object bool inTextObject = false; // Flag showing if the next character is literal // eg '\\' to get a '\' character or '\(' to get '(' bool nextLiteral = false; // () Bracket nesting level. Text appears inside () int bracketDepth = 0; // Keep previous chars to get extract numbers etc.: char[] previousCharacters = new char[_numberOfCharsToKeep]; for (int j = 0; j < _numberOfCharsToKeep; j++) previousCharacters[j] = ' '; for (int i = 0; i < input.Length; i++) { char c = (char)input[i]; if (input[i] == 213) c = "'".ToCharArray()[0]; if (inTextObject) { // Position the text if (bracketDepth == 0) { if (CheckToken(new string[] { "TD", "Td" }, previousCharacters)) { resultString += "\n\r"; } else { if (CheckToken(new string[] { "'", "T*", "\"" }, previousCharacters)) { resultString += "\n"; } else { if (CheckToken(new string[] { "Tj" }, previousCharacters)) { resultString += " "; } } } } // End of a text object, also go to a new line. if (bracketDepth == 0 && CheckToken(new string[] { "ET" }, previousCharacters)) { inTextObject = false; resultString += " "; } else { // Start outputting text if ((c == '(') && (bracketDepth == 0) && (!nextLiteral)) { bracketDepth = 1; } else { // Stop outputting text if ((c == ')') && (bracketDepth == 1) && (!nextLiteral)) { bracketDepth = 0; } else { // Just a normal text character: if (bracketDepth == 1) { // Only print out next character no matter what. // Do not interpret. if (c == '\\' && !nextLiteral) { resultString += c.ToString(); nextLiteral = true; } else { if (((c >= ' ') && (c <= '~')) || ((c >= 128) && (c < 255))) { resultString += c.ToString(); } nextLiteral = false; } } } } } } // Store the recent characters for // when we have to go back for a checking for (int j = 0; j < _numberOfCharsToKeep - 1; j++) { previousCharacters[j] = previousCharacters[j + 1]; } previousCharacters[_numberOfCharsToKeep - 1] = c; // Start of a text object if (!inTextObject && CheckToken(new string[] { "BT" }, previousCharacters)) { inTextObject = true; } } return CleanupContent(resultString); } catch { return ""; } } private string CleanupContent(string text) { string[] patterns = { @"\\\(", @"\\\)", @"\\226", @"\\222", @"\\223", @"\\224", @"\\340", @"\\342", @"\\344", @"\\300", @"\\302", @"\\304", @"\\351", @"\\350", @"\\352", @"\\353", @"\\311", @"\\310", @"\\312", @"\\313", @"\\362", @"\\364", @"\\366", @"\\322", @"\\324", @"\\326", @"\\354", @"\\356", @"\\357", @"\\314", @"\\316", @"\\317", @"\\347", @"\\307", @"\\371", @"\\373", @"\\374", @"\\331", @"\\333", @"\\334", @"\\256", @"\\231", @"\\253", @"\\273", @"\\251", @"\\221"}; string[] replace = { "(", ")", "-", "'", "\"", "\"", "à", "â", "ä", "À", "Â", "Ä", "é", "è", "ê", "ë", "É", "È", "Ê", "Ë", "ò", "ô", "ö", "Ò", "Ô", "Ö", "ì", "î", "ï", "Ì", "Î", "Ï", "ç", "Ç", "ù", "û", "ü", "Ù", "Û", "Ü", "®", "™", "«", "»", "©", "'" }; for (int i = 0; i < patterns.Length; i++) { string regExPattern = patterns[i]; Regex regex = new Regex(regExPattern, RegexOptions.IgnoreCase); text = regex.Replace(text, replace[i]); } return text; } #endregion #region CheckToken /// <summary> /// Check if a certain 2 character token just came along (eg BT) /// </summary> /// <param name="tokens">the searched token</param> /// <param name="recent">the recent character array</param> /// <returns></returns> private bool CheckToken(string[] tokens, char[] recent) { foreach (string token in tokens) { if ((recent[_numberOfCharsToKeep - 3] == token[0]) && (recent[_numberOfCharsToKeep - 2] == token[1]) && ((recent[_numberOfCharsToKeep - 1] == ' ') || (recent[_numberOfCharsToKeep - 1] == 0x0d) || (recent[_numberOfCharsToKeep - 1] == 0x0a)) && ((recent[_numberOfCharsToKeep - 4] == ' ') || (recent[_numberOfCharsToKeep - 4] == 0x0d) || (recent[_numberOfCharsToKeep - 4] == 0x0a)) ) { return true; } } return false; } #endregion } } 由于这个问题最后在2008年得到了回答，iTextSharp大大改善了他们的api。 如果您从http://sourceforge.net/projects/itextsharp/下载最新版本的api，则可以使用以下代码片段将pdf中的所有文本提取为string。;
using iTextSharp.text.pdf; using iTextSharp.text.pdf.parser; namespace PdfParser { public static class PdfTextExtractor { public static string pdfText(string path) { PdfReader reader = new PdfReader(path); string text = string.Empty; for(int page = 1; page <= reader.NumberOfPages; page++) { text += PdfTextExtractor.GetTextFromPage(reader,page); } reader.Close(); return text; } } }
过去我曾经使用过ITextSharp来操作/分割和改造PDF文档 – 这非常简单，也是开源的。
public string ReadPdfFile(object Filename, DataTable ReadLibray) { PdfReader reader2 = new PdfReader((string)Filename); string strText = string.Empty; for (int page = 1; page <= reader2.NumberOfPages; page++) { ITextExtractionStrategy its = new iTextSharp.text.pdf.parser.SimpleTextExtractionStrategy(); PdfReader reader = new PdfReader((string)Filename); String s = PdfTextExtractor.GetTextFromPage(reader, page, its); s = Encoding.UTF8.GetString(ASCIIEncoding.Convert(Encoding.Default, Encoding.UTF8, Encoding.Default.GetBytes(s))); strText = strText + s; reader.Close(); } return strText; }
PDFClown可能会帮助，但我不会推荐它用于大型或重度使用的应用程序。
iText是我认识的最好的图书馆。 最初用Java编写，也有一个.NET端口。
aspose pdf的作品相当不错。 那么，你必须付钱
你可以看看这个： http : //www.codeproject.com/KB/showcase/pdfrasterizer.aspx它不是完全免费的，但它看起来非常好。
亚历克斯
也有LibHaru
看看Docotic.Pdf库 。 它不需要你打开你的应用程序的源代码（例如iTextSharp具有病毒AGPL 3许可证）。
Docotic.Pdf可以用来阅读PDF文件，并提取文本格式或不格式。 请查看展示如何从PDF中提取文本的示例。
免责声明：我为图书馆的供应商Bit Miracle工作。
