Extracting text from a PDF file

Question

I'm using PDFBox for a C# .NET project. and I'm getting a "TypeInitializationException" (The type initializer for 'java.lang.Throwable' threw an exception.) when executing the following block of code :

  FileStream stream = new FileStream(@"C:\1.pdf",FileMode.Open);

  //retrieve the pdf bytes from the stream.
  byte[] pdfbytes=new byte[65000];

  stream.Read(pdfbytes, 0, 65000);

 //get the pdf file bytes.
 allbytes = pdfbytes;

 //create a stream from the file bytes.
 java.io.InputStream ins = new java.io.ByteArrayInputStream(allbytes);
 string txt;

 //load the doc
 PDDocument doc = PDDocument.load(ins);
 PDFTextStripper stripper = new PDFTextStripper();

 //retrieve the pdf doc's text
 txt = stripper.getText(doc);
 doc.close();

the exception occurs at the 3rd statement :

PDDocument doc = PDDocument.load(ins);

What can I do to solve this ?

This is the stack trace :

           at java.lang.Throwable.__<map>(Exception , Boolean )
   at org.pdfbox.pdfparser.PDFParser.parse()
   at org.pdfbox.pdmodel.PDDocument.load(InputStream input, RandomAccess scratchFile)
   at org.pdfbox.pdmodel.PDDocument.load(InputStream input)
   at At.At.ExtractTextFromPDF(InputStream fileStream) in
 C:\Users\Administrator\Documents\Visual Studio 2008\Projects\AtProject\Att\At.cs:line 61

Inner Exception of the InnerException :

• InnerException {"Could not load file or assembly 'IKVM.Runtime, Version=0.30.0.0, Culture=neutral, PublicKeyToken=13235d27fcbfff58' or one of its dependencies. The system cannot find the file specified.":"IKVM.Runtime, Version=0.30.0.0, Culture=neutral, PublicKeyToken=13235d27fcbfff58"} System.Exception {System.IO.FileNotFoundException}

OK, I solved the previous problem by copying some .dll files of the PDFBox to my bin folder. but now I'm getting this error : expected='/' actual='.'--1 org.pdfbox.io.PushBackInputStream@283d742

Are there any alternatives to using PDFBox ? is there any other reliable library out there I can use to extract text from pdf files.

Answer 1

It looks like you missing some library for PDFBox. You need:

• IKVM.GNU.Classpath.dll
• PDFBox-XXXdll
• FontBox-XXX-dev.dll
• IKVM.Runtime.dll

Read this topic Read from a PDF file using C# . You can find the discussion of similar problem in comments of this topic.

Answer 2

I found the versions of the DLL files were the culprits. Go to http://www.netlikon.de/docs/PDFBox-0.7.2/bin/?C=M;O=A and download the following files:

• IKVM.Runtime.dll
• IKVM.GNU.Classpath.dll
• PDFBox-0.7.2.dll

Then copy them into the root of your Visual Studio project. Right click the project and add reference, find all 3 and add them.

Finally here's the code I used to parse the PDF into Text

C#

private static string TransformPdfToText(string SourceFile)
{
string content = "";
PDDocument doc = new PDDocument();
PDFTextStripper stripper = new PDFTextStripper();
doc.close();
doc = PDDocument.load(SourceFile);

try
{
content = stripper.getText(doc);
doc.close();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
finally
{
doc.close();
}
return content;
}

Visual Basic

Private Function parseUsingPDFBox(ByVal filename As String) As String
    LogFile(" Attempting to parse file: " & filename)
    Dim doc As PDDocument = New PDDocument()
    Dim stripper As PDFTextStripper = New PDFTextStripper()
    doc.close()
    doc = PDDocument.load(filename)

    Dim content As String = "empty"
    Try
        content = stripper.getText(doc)
        doc.close()
    Catch ex As Exception
         LogFile(" Error parsing file: " & filename & vbcrlf & ex.Message)
    Finally
        doc.close()
    End Try
    Return content
End Function