从Java Servlet下载时文件损坏

Question

I have a process in a servlet that creates a .pdf file and sends it to the client. However, Adobe won't open the downloaded file ("There was an error opening this document. The file is damaged and could not be repaired."). The original created file residing on the server is fine and Adobe doesn't have a problem opening it.

My code:

private static void sendFile(HttpServletResponse response, String pdfPath) throws FileNotFoundException, IOException {
    PrintWriter out = response.getWriter();
    File f = new File(pdfPath);

    response.setHeader("Content-Transfer-Encoding", "binary");
    response.setHeader("Content-Disposition", "attachment; filename=\"" + f.getName());
    response.setContentLength((int) f.length());

    response.setContentType("application/pdf");

    FileInputStream fileInputStream = new FileInputStream(pdfPath);

    int i;
    while ((i = fileInputStream.read()) != -1) {
        out.write(i);
    }
    fileInputStream.close();
    out.close();
}

Answer 1

A Writer writes characters , not bytes.

Use the response output stream .

And don't read and write byte by byte, especially from a FileInputStream .This is extremely inefficient. Just use Files.copy() .