You can use PdfBox from Apache which is simple to use and has good performance.
Here is an example of extracting text from a PDF file (you can read more here) :
import java.io.*;
import org.apache.pdfbox.pdmodel.*;
import org.apache.pdfbox.util.*;
public class PDFTest {
public static void main(String[] args){
PDDocument pd;
BufferedWriter wr;
try {
File input = new File("C:\\Invoice.pdf"); // The PDF file from where you would like to extract
File output = new File("C:\\SampleText.txt"); // The text file where you are going to store the extracted data
pd = PDDocument.load(input);
System.out.println(pd.getNumberOfPages());
System.out.println(pd.isEncrypted());
pd.save("CopyOfInvoice.pdf"); // Creates a copy called "CopyOfInvoice.pdf"
PDFTextStripper stripper = new PDFTextStripper();
wr = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(output)));
stripper.writeText(pd, wr);
if (pd != null) {
pd.close();
}
// I use close() to flush the stream.
wr.close();
} catch (Exception e){
e.printStackTrace();
}
}
}
UPDATE:
You can get the text using PDFTextStripper:
PDFTextStripper reader = new PDFTextStripper();
String pageText = reader.getText(pd); // PDDocument object created