Question

I have the following situation, within a servlet a create a file and then have to delete it.
When executing the file, I figured out that the file is still in the server, so I tried to remove it manually, I can’t, I get the following message :

this file is opened by another program : javaw.exe

Here is my code :

public class GenerateFile extends Action { 
    public ActionForward execute(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response) throws IOException {
        System.out.println("ok");
        String fileName = request.getParameter("fileName");
        Integer nbrParam = Integer.parseInt(request.getParameter("nbrParam"));
        String[] valueParam = new String[nbrParam+1];
        for(int i =1;i<=nbrParam;i++)
        {  System.out.println(request.getParameter("param"+i));
            valueParam[i]=request.getParameter("param"+i);
        }
        FileInputStream in = new FileInputStream("C:\\Users\\free\\Desktop\\myworkspace\\gestionRH\\WebRoot\\fiches\\"+fileName+".doc");
        POIFSFileSystem fs = new POIFSFileSystem(in);
        HWPFDocument doc = new HWPFDocument(fs);
        Range r = doc.getRange();
        for(int i=1;i<=nbrParam;i++)
        {   System.out.println("<param"+i+">");
            System.out.println(valueParam[i]);
            r.replaceText("<param"+i+">", valueParam[i]);
        }
        File  file = new File("C:\\Users\\free\\Desktop\\myworkspace\\gestionRH\\WebRoot\\fiches\\temp");
        File temp = File.createTempFile("monfile",".doc",file);
        String tempName =temp.getName();
        doc.write( new FileOutputStream(temp));
        OutputStream out = response.getOutputStream();
        response.setContentType("application/rtf");
        response.setHeader("Content-Disposition","attachment; filename=Decision");
        FileInputStream in1 = new FileInputStream(temp);
        byte[] buffer = new byte[4096];
        int length;

        while ((length = in1.read(buffer)) > 0){
            out.write(buffer, 0, length);
        }
        in1.close();
        out.flush();
        System.out.println("C:\\Users\\free\\Desktop\\myworkspace\\gestionRH\\WebRoot\\fiches\\temp\\"+tempName);
        File f = new File("C:\\Users\\free\\Desktop\\myworkspace\\gestionRH\\WebRoot\\fiches\\temp\\"+tempName);
        f.delete();

        return null;
    }
}

Answer 1

The problem is you are creating a new FileOutputStream(tempName) to write on that file, but never closing that outputstream (or another outputstream linked to it).

Do this:

FileOutputStream fos = newFileOutputStream(tempName);
// use it
fos.close(); // CLOSE IT!!

// then you can delete the file

Simplify

Maybe you could do the work another way, without temp files…

by example: doc.write(new FileOutputStream(tempName)) could be replaced by:

doc.write(response.getOutputStream());

This way doc sends its bytes directly to where you need them, not to a temp file eliminating the need for it.

The idea behind input/output streams is composing them. Input/OutputStream are the abstract base classes. And there are a lot of implementations:

• based on memory: ByteArrayInput/OutputStream
• based on files: FileInputOutputStream
• compressing/decompressing to another outputstream: GZipInputOutputStream
• and so on

The beauty of it is applying decorator pattern to add functionality. By example:

new GZipOutputStream(new ByteArrayOutputStream());

// creates an outputstreams that compress data received and send it to the other stream
// the BAOS then writes the received bytes to memory


new GZipOutputStream(new FileOutputStream());
// it's the same but sending compressed bytes to a file.