У пользователей слабый интернет, и бывает связь разрывается.
Отправляю файл так
FileInputStream inputStream = new FileInputStream(downloadFile);
// get MIME type of the file
String mimeType = context.getMimeType(file.toString());
if (mimeType == null) {
// set to binary type if MIME mapping not found
mimeType = "application/octet-stream";
}
// set content attributes for the response
response.setContentType(mimeType);
response.setContentLength((int) downloadFile.length());
// set headers for the response
String headerKey = "Content-Disposition";
String headerValue = String.format("attachment; filename*0*=utf-8''\"%s\"",
URLEncoder.encode(downloadFile.getName(), "UTF-8"));
response.setHeader(headerKey, headerValue);
// get output stream of the response
OutputStream outStream = null;
try {
outStream = response.getOutputStream();
} catch (IOException e) {
e.printStackTrace();
}
byte[] buffer = new byte[4096];
int bytesRead = -1;
// write bytes read from the input stream into the output stream
try {
while ((bytesRead = inputStream.read(buffer)) != -1) {
outStream.write(buffer, 0, bytesRead);
}
} catch (IOException e) {
e.printStackTrace();
}
inputStream.close();
outStream.close();
return null;
}
Возможно ли добавить реализацию докачки файла если допустим у пользователя оборвалась
связь либо он поставил на паузу?
Ответы
Ответ 1
Используйте jetty, есть готовый проект по вашему случаю -> https://github.com/spring-projects/spring-boot/tree/master/spring-boot-samples/spring-boot-sample-websocket-jetty
А изобретать костыли с использованием WebSocket не комильфо.
Или пробуйте стандартными средствами RMI - быстро/проверенно
Ответ 2
Кому интересно, воспользовался этим методом. Всё работает, подкачка поддерживается.
https://gist.github.com/davinkevin/b97e39d7ce89198774b4
MultipartFileSender.fromPath(file.getLocalPath())
.with(request)
.with(response)
.serveResource();
public class MultipartFileSender {
protected final Logger logger = LoggerFactory.getLogger(this.getClass());
private static final int DEFAULT_BUFFER_SIZE = 20480; // ..bytes = 20KB.
private static final long DEFAULT_EXPIRE_TIME = 604800000L; // ..ms = 1 week.
private static final String MULTIPART_BOUNDARY = "MULTIPART_BYTERANGES";
Path filepath;
HttpServletRequest request;
HttpServletResponse response;
public MultipartFileSender() {
}
public static MultipartFileSender fromPath(Path path) {
return new MultipartFileSender().setFilepath(path);
}
public static MultipartFileSender fromFile(File file) {
return new MultipartFileSender().setFilepath(file.toPath());
}
public static MultipartFileSender fromURIString(String uri) {
return new MultipartFileSender().setFilepath(Paths.get(uri));
}
//** internal setter **//
private MultipartFileSender setFilepath(Path filepath) {
this.filepath = filepath;
return this;
}
public MultipartFileSender with(HttpServletRequest httpRequest) {
request = httpRequest;
return this;
}
public MultipartFileSender with(HttpServletResponse httpResponse) {
response = httpResponse;
return this;
}
public void serveResource() throws Exception {
if (response == null || request == null) {
return;
}
if (!Files.exists(filepath)) {
logger.error("File doesn't exist at URI : {}", filepath.toAbsolutePath().toString());
response.sendError(HttpServletResponse.SC_NOT_FOUND);
return;
}
Long length = Files.size(filepath);
String fileName = filepath.getFileName().toString();
FileTime lastModifiedObj = Files.getLastModifiedTime(filepath);
if (StringUtils.isEmpty(fileName) || lastModifiedObj == null) {
response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
return;
}
long lastModified = LocalDateTime.ofInstant(lastModifiedObj.toInstant(),
ZoneId.of(ZoneOffset.systemDefault().getId())).toEpochSecond(ZoneOffset.UTC);
String contentType = MimeTypeUtils.probeContentType(filepath);
// Validate request headers for caching ---------------------------------------------------
// If-None-Match header should contain "*" or ETag. If so, then return 304.
String ifNoneMatch = request.getHeader("If-None-Match");
if (ifNoneMatch != null && HttpUtils.matches(ifNoneMatch, fileName)) {
response.setHeader("ETag", fileName); // Required in 304.
response.sendError(HttpServletResponse.SC_NOT_MODIFIED);
return;
}
// If-Modified-Since header should be greater than LastModified. If so, then
return 304.
// This header is ignored if any If-None-Match header is specified.
long ifModifiedSince = request.getDateHeader("If-Modified-Since");
if (ifNoneMatch == null && ifModifiedSince != -1 && ifModifiedSince + 1000
> lastModified) {
response.setHeader("ETag", fileName); // Required in 304.
response.sendError(HttpServletResponse.SC_NOT_MODIFIED);
return;
}
// Validate request headers for resume ----------------------------------------------------
// If-Match header should contain "*" or ETag. If not, then return 412.
String ifMatch = request.getHeader("If-Match");
if (ifMatch != null && !HttpUtils.matches(ifMatch, fileName)) {
response.sendError(HttpServletResponse.SC_PRECONDITION_FAILED);
return;
}
// If-Unmodified-Since header should be greater than LastModified. If not,
then return 412.
long ifUnmodifiedSince = request.getDateHeader("If-Unmodified-Since");
if (ifUnmodifiedSince != -1 && ifUnmodifiedSince + 1000 <= lastModified) {
response.sendError(HttpServletResponse.SC_PRECONDITION_FAILED);
return;
}
// Validate and process range -------------------------------------------------------------
// Prepare some variables. The full Range represents the complete file.
Range full = new Range(0, length - 1, length);
List ranges = new ArrayList<>();
// Validate and process Range and If-Range headers.
String range = request.getHeader("Range");
if (range != null) {
// Range header should match format "bytes=n-n,n-n,n-n...". If not, then
return 416.
if (!range.matches("^bytes=\\d*-\\d*(,\\d*-\\d*)*$")) {
response.setHeader("Content-Range", "bytes */" + length); // Required
in 416.
response.sendError(HttpServletResponse.SC_REQUESTED_RANGE_NOT_SATISFIABLE);
return;
}
String ifRange = request.getHeader("If-Range");
if (ifRange != null && !ifRange.equals(fileName)) {
try {
long ifRangeTime = request.getDateHeader("If-Range"); // Throws
IAE if invalid.
if (ifRangeTime != -1) {
ranges.add(full);
}
} catch (IllegalArgumentException ignore) {
ranges.add(full);
}
}
// If any valid If-Range header, then process each part of byte range.
if (ranges.isEmpty()) {
for (String part : range.substring(6).split(",")) {
// Assuming a file with length of 100, the following examples
returns bytes at:
// 50-80 (50 to 80), 40- (40 to length=100), -20 (length-20=80
to length=100).
long start = Range.sublong(part, 0, part.indexOf("-"));
long end = Range.sublong(part, part.indexOf("-") + 1, part.length());
if (start == -1) {
start = length - end;
end = length - 1;
} else if (end == -1 || end > length - 1) {
end = length - 1;
}
// Check if Range is syntactically valid. If not, then return 416.
if (start > end) {
response.setHeader("Content-Range", "bytes */" + length);
// Required in 416.
response.sendError(HttpServletResponse.SC_REQUESTED_RANGE_NOT_SATISFIABLE);
return;
}
// Add range.
ranges.add(new Range(start, end, length));
}
}
}
// Prepare and initialize response --------------------------------------------------------
// Get content type by file name and set content disposition.
String disposition = "inline";
// If content type is unknown, then set the default value.
// For all content types, see: http://www.w3schools.com/media/media_mimeref.asp
// To add new content types, add new mime-mapping entry in web.xml.
if (contentType == null) {
contentType = "application/octet-stream";
} else if (!contentType.startsWith("image")) {
// Else, expect for images, determine content disposition. If content
type is supported by
// the browser, then set to inline, else attachment which will pop a
'save as' dialogue.
String accept = request.getHeader("Accept");
disposition = accept != null && HttpUtils.accepts(accept, contentType)
? "inline" : "attachment";
}
logger.debug("Content-Type : {}", contentType);
// Initialize response.
response.reset();
response.setBufferSize(DEFAULT_BUFFER_SIZE);
response.setHeader("Content-Type", contentType);
response.setHeader("Content-Disposition", disposition + ";filename=\"" +
fileName + "\"");
logger.debug("Content-Disposition : {}", disposition);
response.setHeader("Accept-Ranges", "bytes");
response.setHeader("ETag", fileName);
response.setDateHeader("Last-Modified", lastModified);
response.setDateHeader("Expires", System.currentTimeMillis() + DEFAULT_EXPIRE_TIME);
// Send requested file (part(s)) to client ------------------------------------------------
// Prepare streams.
try (InputStream input = new BufferedInputStream(Files.newInputStream(filepath));
OutputStream output = response.getOutputStream()) {
if (ranges.isEmpty() || ranges.get(0) == full) {
// Return full file.
logger.info("Return full file");
response.setContentType(contentType);
response.setHeader("Content-Range", "bytes " + full.start + "-" +
full.end + "/" + full.total);
response.setHeader("Content-Length", String.valueOf(full.length));
Range.copy(input, output, length, full.start, full.length);
} else if (ranges.size() == 1) {
// Return single part of file.
Range r = ranges.get(0);
logger.info("Return 1 part of file : from ({}) to ({})", r.start, r.end);
response.setContentType(contentType);
response.setHeader("Content-Range", "bytes " + r.start + "-" + r.end
+ "/" + r.total);
response.setHeader("Content-Length", String.valueOf(r.length));
response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT); // 206.
// Copy single part range.
Range.copy(input, output, length, r.start, r.length);
} else {
// Return multiple parts of file.
response.setContentType("multipart/byteranges; boundary=" + MULTIPART_BOUNDARY);
response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT); // 206.
// Cast back to ServletOutputStream to get the easy println methods.
ServletOutputStream sos = (ServletOutputStream) output;
// Copy multi part range.
for (Range r : ranges) {
logger.info("Return multi part of file : from ({}) to ({})",
r.start, r.end);
// Add multipart boundary and header fields for every range.
sos.println();
sos.println("--" + MULTIPART_BOUNDARY);
sos.println("Content-Type: " + contentType);
sos.println("Content-Range: bytes " + r.start + "-" + r.end +
"/" + r.total);
// Copy single part range of multi part range.
Range.copy(input, output, length, r.start, r.length);
}
// End with multipart boundary.
sos.println();
sos.println("--" + MULTIPART_BOUNDARY + "--");
}
}
}
private static class Range {
long start;
long end;
long length;
long total;
/**
* Construct a byte range.
* @param start Start of the byte range.
* @param end End of the byte range.
* @param total Total length of the byte source.
*/
public Range(long start, long end, long total) {
this.start = start;
this.end = end;
this.length = end - start + 1;
this.total = total;
}
public static long sublong(String value, int beginIndex, int endIndex) {
String substring = value.substring(beginIndex, endIndex);
return (substring.length() > 0) ? Long.parseLong(substring) : -1;
}
private static void copy(InputStream input, OutputStream output, long inputSize,
long start, long length) throws IOException {
byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
int read;
if (inputSize == length) {
// Write full range.
while ((read = input.read(buffer)) > 0) {
output.write(buffer, 0, read);
output.flush();
}
} else {
input.skip(start);
long toRead = length;
while ((read = input.read(buffer)) > 0) {
if ((toRead -= read) > 0) {
output.write(buffer, 0, read);
output.flush();
} else {
output.write(buffer, 0, (int) toRead + read);
output.flush();
break;
}
}
}
}
}
private static class HttpUtils {
/**
* Returns true if the given accept header accepts the given value.
* @param acceptHeader The accept header.
* @param toAccept The value to be accepted.
* @return True if the given accept header accepts the given value.
*/
public static boolean accepts(String acceptHeader, String toAccept) {
String[] acceptValues = acceptHeader.split("\\s*(,|;)\\s*");
Arrays.sort(acceptValues);
return Arrays.binarySearch(acceptValues, toAccept) > -1
|| Arrays.binarySearch(acceptValues, toAccept.replaceAll("/.*$",
"/*")) > -1
|| Arrays.binarySearch(acceptValues, "*/*") > -1;
}
/**
* Returns true if the given match header matches the given value.
* @param matchHeader The match header.
* @param toMatch The value to be matched.
* @return True if the given match header matches the given value.
*/
public static boolean matches(String matchHeader, String toMatch) {
String[] matchValues = matchHeader.split("\\s*,\\s*");
Arrays.sort(matchValues);
return Arrays.binarySearch(matchValues, toMatch) > -1
|| Arrays.binarySearch(matchValues, "*") > -1;
}
}
}
