restfulファイルダウンロード機能実装

        private static final byte[] UTF8_BOM = {(byte)0xEF, (byte)0xBB, (byte)0xBF};
        private static final String FAV_ICO = "fav.ico";
        @GET
        @Path("/getFile")
        @Produces(MediaType.APPLICATION_OCTET_STREAM)
        public Response getFile(@PathParam("fileName") String fileName) throws IOException{
            ByteArrayOutputStream bos = new ByteArrayOutputStream();

            ZipOutputStream zos = new ZipOutputStream(bos);

            try {
              zos.putNextEntry(new ZipEntry("utf-8.txt"));
              zos.write(UTF8_BOM);
              zos.write(" UTF-8 ".getBytes("UTF-8"));
              zos.closeEntry();
              zos.flush();
              zos.finish();
              return Response.ok(bos.toByteArray(), "application/zip")
                .header("Content-Disposition", "attachment; filename=demo2.zip")
                .build();
            } catch (IOException e) {
              throw new RuntimeException(e);
            } finally {
              try {
                zos.close();
              } catch (IOException e) {}
            }
        }

        @GET
        @Path("/getMyFile")
        @Produces(MediaType.APPLICATION_OCTET_STREAM)
        public Response getMyFile() throws IOException{
            File file = new File("123.txt");
            file.createNewFile();
            long fileLength = file.length();
            ResponseBuilder responseBuilder = Response.ok(file);
            responseBuilder.type("application/x-msdownload");
            responseBuilder.header("Content-Disposition", "attachment; filename="
                    + URLEncoder.encode("123.txt", "UTF-8"));
            responseBuilder.header("Content-Length", Long.toString(fileLength));
            Response response = responseBuilder.build();
            return response;
        }