Java - File Download using HttpServletResponse - File gets corrupted after Download

Question

I am trying to download file from my local file system after form submit. I am getting the FileInputStream and writing to the HttpServletResponse using the below code .

        PrintWriter out = response.getWriter();
        response.setCharacterEncoding("UTF-8");
        String filename = "DSR.xlsx";   
        response.setContentType("application/octet-stream");   
        response.setHeader("Content-Disposition","attachment; filename=\"" + filename + "\"");   

        FileInputStream fileInputStream = new FileInputStream("C://Users/Metro/Desktop/DSR.xlsx");  

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

File is getting downloaded but file is corrupted . It works in case of text files only. I want the code to work in case of .xlsx, .pdf, .jpg etc.

Answer 1

Here the problem is with ContentType.

You have to set content type related to file extention.

For excel

response.setContentType("application/vnd.ms-excel")

For pdf

response.setContentType("application/pdf")

For jpg

response.setContentType("image/jpeg")

[refer this link to know all mime types]

https://www.sitepoint.com/mime-types-complete-list/

Answer 2

I resolved the issue using java.nio.file.Files.copy(Path source, OutputStream out).

        response.setCharacterEncoding("UTF-8");
        String filename = "DSR.xlsx";   
        response.setContentType("application/octet-stream");   
        response.setHeader("Content-Disposition","attachment; filename=\"" + filename + "\"");   

        try (OutputStream out = response.getOutputStream()){
            File toBeCopied = new File("C://Users/Metro/Desktop/DSR.xlsx");
            Path path = toBeCopied.toPath();
            Files.copy(path, out);
            out.flush();
        }catch(IOException e){
            e.printStackTrace();
        }

It works in case of any file type (.jpg , .xlsx, .pdf )