我该如何使用itextsharp的Pdfreader类读取PDF内容。我的PDF文件可能包含纯文本或文字图像。
using iTextSharp.text.pdf;
using iTextSharp.text.pdf.parser;
using System.IO;
public string ReadPdfFile(string fileName)
{
StringBuilder text = new StringBuilder();
if (File.Exists(fileName))
{
PdfReader pdfReader = new PdfReader(fileName);
for (int page = 1; page <= pdfReader.NumberOfPages; page++)
{
ITextExtractionStrategy strategy = new SimpleTextExtractionStrategy();
string currentText = PdfTextExtractor.GetTextFromPage(pdfReader, page, strategy);
currentText = Encoding.UTF8.GetString(ASCIIEncoding.Convert(Encoding.Default, Encoding.UTF8, Encoding.Default.GetBytes(currentText)));
text.Append(currentText);
}
pdfReader.Close();
}
return text.ToString();
}
.Close()
пЉМиАМдЄНжШѓusing (var pdfReader = ...) {}
пЉЯ - SebastianASCIIEncoding.Convert
应该改为 Encoding.Convert
,因为它是一个静态方法。 - Sebastianvar pdfReader = new PdfReader(path); //other filestream etc
byte[] pageContent = _pdfReader .GetPageContent(pageNum); //not zero based
byte[] utf8 = Encoding.Convert(Encoding.Default, Encoding.UTF8, pageContent);
string textFromPage = Encoding.UTF8.GetString(utf8);
const string PdfTableFormat = @"\(.*\)Tj";
Regex PdfTableRegex = new Regex(PdfTableFormat, RegexOptions.Compiled);
List<string> ExtractPdfContent(string rawPdfContent)
{
var matches = PdfTableRegex.Matches(rawPdfContent);
var list = matches.Cast<Match>()
.Select(m => m.Value
.Substring(1) //remove leading (
.Remove(m.Value.Length - 4) //remove trailing )Tj
.Replace(@"\)", ")") //unencode parens
.Replace(@"\(", "(")
.Trim()
)
.ToList();
return list;
}
Foo(bar)
,那么它在PDF中将被编码为(Foo\(bar\))Tj
,该方法将返回预期的Foo(bar)
。此方法将从原始PDF内容中剥离出许多其他信息,例如位置坐标。这是基于ShravankumarKumar方案的VB.NET解决方案。
这仅会给您文本内容。图片需要另行处理。
Public Shared Function GetTextFromPDF(PdfFileName As String) As String
Dim oReader As New iTextSharp.text.pdf.PdfReader(PdfFileName)
Dim sOut = ""
For i = 1 To oReader.NumberOfPages
Dim its As New iTextSharp.text.pdf.parser.SimpleTextExtractionStrategy
sOut &= iTextSharp.text.pdf.parser.PdfTextExtractor.GetTextFromPage(oReader, i, its)
Next
Return sOut
End Function
Rectangle _pdfRect = new Rectangle(0f, 0f, 612f, 792f); // Entire page - PDF coordinate system 0,0 is bottom left corner. 72 points / inch
RenderFilter _renderfilter = new RegionTextRenderFilter(_pdfRect);
ITextExtractionStrategy _strategy = new FilteredTextRenderListener(new LocationTextExtractionStrategy(), _filter);
string _text = PdfTextExtractor.GetTextFromPage(_pdfReader, 1, _strategy);
正如上面的评论所指出的那样,生成的文本不保留PDF文档中的任何格式,但我很高兴它确实保留了回车符。在我的情况下,文本中有足够的常量,我能够提取所需的值。
这里是ShravankumarKumar的改进答案。我创建了特殊的类用于页面,因此您可以基于文本行和该行中的单词访问pdf中的单词。
using iTextSharp.text.pdf;
using iTextSharp.text.pdf.parser;
//create a list of pdf pages
var pages = new List<PdfPage>();
//load the pdf into the reader. NOTE: path can also be replaced with a byte array
using (PdfReader reader = new PdfReader(path))
{
//loop all the pages and extract the text
for (int i = 1; i <= reader.NumberOfPages; i++)
{
pages.Add(new PdfPage()
{
content = PdfTextExtractor.GetTextFromPage(reader, i)
});
}
}
//use linq to create the rows and words by splitting on newline and space
pages.ForEach(x => x.rows = x.content.Split('\n').Select(y =>
new PdfRow() {
content = y,
words = y.Split(' ').ToList()
}
).ToList());
class PdfPage
{
public string content { get; set; }
public List<PdfRow> rows { get; set; }
}
class PdfRow
{
public string content { get; set; }
public List<string> words { get; set; }
}
string myWord = pages[0].rows[12].words[4];
或者使用Linq查找包含特定单词的行。
//find the rows in a specific page containing a word
var myRows = pages[0].rows.Where(x => x.words.Any(y => y == "myWord1")).ToList();
//find the rows in all pages containing a word
var myRows = pages.SelectMany(r => r.rows).Where(x => x.words.Any(y => y == "myWord2")).ToList();
Public Sub PDFTxtToPdf(ByVal sTxtfile As String, ByVal sPDFSourcefile As String)
Dim sr As StreamReader = New StreamReader(sTxtfile)
Dim doc As New Document()
PdfWriter.GetInstance(doc, New FileStream(sPDFSourcefile, FileMode.Create))
doc.Open()
doc.Add(New Paragraph(sr.ReadToEnd()))
doc.Close()
End Sub