After spending several hours aggregating data from numerous sources, I decided to compose this article. The code has been tested in IE, Chrome and Firefox. I want to save a file with name «мале нький.txt» — I added a white space intentionally to test this case. Please follow the link for details.
I will stick to the crucial aspect — creation of a proper header.
import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; ... private static final String CONTENT_DISP_PREFIX = "attachment; filename="; private static final String CONTENT_DISP_EXTRA_PREFIX = "attachment; filename*=UTF-8''"; private static final String USER_AGENT_FIREFOX = "Firefox"; ... @RequestMapping(value = "get/{fileId}", method = RequestMethod.GET) @ResponseBody public void getFile(@PathVariable("fileId") Long fileId, HttpServletRequest request, HttpServletResponse response) { String ua = request.getHeader(HttpHeaders.USER_AGENT); // we are in controller's method which handles requests for a file and sends response with it String filename = "мале нький.txt"; String encodedFileName = null; try { // Specific handling for non-ASCII characters encodedFileName = rfc5987_encode(attachedFile.getFileName()); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } if (!ua.contains(USER_AGENT_FIREFOX)) { response.setHeader(CONTENT_DISP_HEADER, CONTENT_DISP_PREFIX + "\"" + encodedFileName + "\""); } else { response.setHeader(CONTENT_DISP_HEADER, CONTENT_DISP_EXTRA_PREFIX + encodedFileName ); } ... |
Encoding method:
public static String rfc5987_encode(final String s) throws UnsupportedEncodingException { final byte[] s_bytes = s.getBytes("UTF-8"); final int len = s_bytes.length; final StringBuilder sb = new StringBuilder(len << 1); final char[] digits = {'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'}; final byte[] attr_char = {'!','#','$','&','+','-','.','0','1','2','3','4','5','6','7','8','9', 'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z','^','_','`', 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','|', '~'}; for (int i = 0; i < len; ++i) { final byte b = s_bytes[i]; if (Arrays.binarySearch(attr_char, b) >= 0) sb.append((char) b); else { sb.append('%'); sb.append(digits[0x0f & (b >>> 4)]); sb.append(digits[b & 0x0f]); } } return sb.toString(); } |