Reading bytes from compressed PDF file in Java

Question

When I try to read bytes from a normal PDF file into a byte array using "read" function in Java, the byte array is loaded correctly with size same as that of original PDF file.

Path file_path = Paths.get("D:\\Zip Test Client", "vadClient1.pdf");
    byte[] ByteArray= Files.readAllBytes(file_path);
    FileOutputStream fos = new FileOutputStream(new File("E:\\newFinalPDF.pdf"));

But when I read bytes from the same PDF file located inside a zipped folder, the read function reads only 8843 bytes (original size is 194471) and rest all are 0.

zipFile = new ZipFile(new File("D:\\Zip test Server\\ZipTestFolderOnServer.zip"));
        long count = zipFile.size();
        Enumeration<? extends ZipEntry> entries = zipFile.entries();
        while(entries.hasMoreElements()){

            System.out.println("New File starting");
            ZipEntry zipEntry = entries.nextElement();
            System.out.println(zipEntry.getName());
            InputStream fis =  zipFile.getInputStream(zipEntry); 
            byte[] fileToBytes = new byte[(int)zipEntry.getSize()];


            FileOutputStream fos = new FileOutputStream(new File("E:\\ContentZipped_"   + zipEntry.getName()));
            fis.read(fileToBytes);
            fos.write(fileToBytes);
            fis.close();
            Thread.sleep(1000);
            --count;
        }

What is the explanation to this behavior?

EDIT 1:- I am not looking for third party integrations such as Tika or POI.

Answer 1

Let's make it less error prone (and less memory consuming) by simplifying the code, use this to copy the content of your zip entry:

try (InputStream fis =  zipFile.getInputStream(zipEntry)) {
    Files.copy(fis, Paths.get("E:\\ContentZipped_"   + zipEntry.getName()));
}

Answer 2

public class SampleZipExtract {

public static void main(String[] args) {

    List<String> tempString = new ArrayList<String>();
    StringBuffer sbf = new StringBuffer();

    File file = new File("C:\\Users\\xxx\\Desktop\\abc.zip");
    InputStream input;
    try {

      input = new FileInputStream(file);
      ZipInputStream zip = new ZipInputStream(input);
      ZipEntry entry = zip.getNextEntry();

      BodyContentHandler textHandler = new BodyContentHandler();
      Metadata metadata = new Metadata();

      Parser parser = new AutoDetectParser();

      while (entry!= null){

            if(entry.getName().endsWith(".txt") || 
                       entry.getName().endsWith(".pdf")||
                       entry.getName().endsWith(".docx")){
          System.out.println("entry=" + entry.getName() + " " + entry.getSize());
                 parser.parse(input, textHandler, metadata, new ParseContext());
                 tempString.add(textHandler.toString());
            }
       }
       zip.close();
       input.close();

       for (String text : tempString) {
       System.out.println("Apache Tika - Converted input string : " + text);
       sbf.append(text);
       System.out.println("Final text from all the three files " + sbf.toString());
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (SAXException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (TikaException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

}