Problem Opening Files converted from Javamail Attachments (io problems)

Question

Hello,
I am streaming a Word doc attachment from a JavaMail Message object, to a file using the code below. The file shows up in the file system as the proper size, but when I attempt to open it, it says "The document or path is invalid". It seems to happen the moment I write even a single line of the stream from the BufferedReader to the DataOutputStream, let alone the entire input stream (simply creating the empty file before streaming between objects, and I can open the file without problems). I would be grateful for any insights. Thank you.
public void capture(TRIMAttachment ta, Part part){
   String filename = path + ta.getDocumentName();
   String attContent = "";
   attachmentFile = new File(filename);
   try {
      FileOutputStream fos = new FileOutputStream(attachmentFile);
      DataOutputStream dos = new DataOutputStream(fos);
      InputStreamReader isr = new InputStreamReader(part.getInputStream());
      BufferedReader br = new BufferedReader(isr);
      String s="";
      while ((s = br.readLine()) != null) {
         attContent=attContent+s;
      dos.writeBytes(attContent);
      br.close();
      isr.close();
      dos.close();
      fos.close();
      }catch(IOException ioe){
         ioe.printStackTrace();
      }catch(MessagingException me){
         me.printStackTrace();
      }

Answer 1

A Word document is not a text file (surprise!). You shouldn't be using
a Reader to read the content. Copy the data to the file using the
InputStream and a FileOutputStream. See the msgshow.java demo
program.