Posso rispondere tramite codice di lavoro? Qui ci sono parti client e server necessarie. Vedi la spiegazione di seguito.
Cliente:
<input id="fileupload" type="file" name="files[]" data-url="file.upload" multiple>
<script>
var uuid = function() {
return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g,
function(c) {
var r = Math.random()*16|0, v = c == 'x' ? r : (r&0x3|0x8);
return v.toString(16);
});
};
$(function() {
$('#fileupload').fileupload({
dataType: 'json',
maxChunkSize: 1000000,
done: function (e, data) {
$.each(data.result.files, function (index, file) {
$('<p/>').text(file.name).appendTo(document.body);
});
}
}).bind('fileuploadsubmit', function (e, data) {
data.formData = {uploadId: uuid()};
});
});
</script>
WEB_INF/web.xml:
<!-- ...other servlet blocks... -->
<servlet>
<servlet-name>fileUploadServlet</servlet-name>
<servlet-class>your.package.FileUploadServlet</servlet-class>
</servlet>
<!-- ...other servlet-mapping blocks... -->
<servlet-mapping>
<servlet-name>fileUploadServlet</servlet-name>
<url-pattern>/file.upload</url-pattern>
</servlet-mapping>
Servlet "FileUploadServlet":
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import java.util.regex.Pattern;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileItemFactory;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import com.fasterxml.jackson.databind.ObjectMapper;
...
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String range = request.getHeader("Content-Range");
long fileFullLength = -1;
long chunkFrom = -1;
long chunkTo = -1;
if (range != null) {
if (!range.startsWith("bytes "))
throw new ServletException("Unexpected range format: " + range);
String[] fromToAndLength = range.substring(6).split(Pattern.quote("/"));
fileFullLength = Long.parseLong(fromToAndLength[1]);
String[] fromAndTo = fromToAndLength[0].split(Pattern.quote("-"));
chunkFrom = Long.parseLong(fromAndTo[0]);
chunkTo = Long.parseLong(fromAndTo[1]);
}
File tempDir = new File(System.getProperty("java.io.tmpdir")); // Configure according
File storageDir = tempDir; // project server environment.
String uploadId = null;
FileItemFactory factory = new DiskFileItemFactory(10000000, tempDir);
ServletFileUpload upload = new ServletFileUpload(factory);
try {
List<?> items = upload.parseRequest(request);
Iterator<?> it = items.iterator();
List<Map<String, Object>> ret = new ArrayList<Map<String,Object>>();
while (it.hasNext()) {
FileItem item = (FileItem) it.next();
if (item.isFormField()) {
if (item.getFieldName().equals("uploadId"))
uploadId = item.getString();
} else {
Map<String, Object> fileInfo = new LinkedHashMap<String, Object>();
File assembledFile = null;
fileInfo.put("name", item.getName());
fileInfo.put("type", item.getContentType());
File dir = new File(storageDir, uploadId);
if (!dir.exists())
dir.mkdir();
if (fileFullLength < 0) { // File is not chunked
fileInfo.put("size", item.getSize());
assembledFile = new File(dir, item.getName());
item.write(assembledFile);
} else { // File is chunked
byte[] bytes = item.get();
if (chunkFrom + bytes.length != chunkTo + 1)
throw new ServletException("Unexpected length of chunk: " + bytes.length +
" != " + (chunkTo + 1) + " - " + chunkFrom);
saveChunk(dir, item.getName(), chunkFrom, bytes, fileFullLength);
TreeMap<Long, Long> chunkStartsToLengths = getChunkStartsToLengths(dir, item.getName());
long lengthSoFar = getCommonLength(chunkStartsToLengths);
fileInfo.put("size", lengthSoFar);
if (lengthSoFar == fileFullLength) {
assembledFile = assembleAndDeleteChunks(dir, item.getName(),
new ArrayList<Long>(chunkStartsToLengths.keySet()));
}
}
if (assembledFile != null) {
fileInfo.put("complete", true);
fileInfo.put("serverPath", assembledFile.getAbsolutePath());
// Here you can do something with fully assembled file.
}
ret.add(fileInfo);
}
}
Map<String, Object> filesInfo = new LinkedHashMap<String, Object>();
filesInfo.put("files", ret);
response.setContentType("application/json");
response.getWriter().write(new ObjectMapper().writeValueAsString(filesInfo));
response.getWriter().close();
} catch (ServletException ex) {
throw ex;
} catch (Exception ex) {
ex.printStackTrace();
throw new ServletException(ex);
}
}
private static void saveChunk(File dir, String fileName,
long from, byte[] bytes, long fileFullLength) throws IOException {
File target = new File(dir, fileName + "." + from + ".chunk");
OutputStream os = new FileOutputStream(target);
try {
os.write(bytes);
} finally {
os.close();
}
}
private static TreeMap<Long, Long> getChunkStartsToLengths(File dir,
String fileName) throws IOException {
TreeMap<Long, Long> chunkStartsToLengths = new TreeMap<Long, Long>();
for (File f : dir.listFiles()) {
String chunkFileName = f.getName();
if (chunkFileName.startsWith(fileName + ".") &&
chunkFileName.endsWith(".chunk")) {
chunkStartsToLengths.put(Long.parseLong(chunkFileName.substring(
fileName.length() + 1, chunkFileName.length() - 6)), f.length());
}
}
return chunkStartsToLengths;
}
private static long getCommonLength(TreeMap<Long, Long> chunkStartsToLengths) {
long ret = 0;
for (long len : chunkStartsToLengths.values())
ret += len;
return ret;
}
private static File assembleAndDeleteChunks(File dir, String fileName,
List<Long> chunkStarts) throws IOException {
File assembledFile = new File(dir, fileName);
if (assembledFile.exists()) // In case chunks come in concurrent way
return assembledFile;
OutputStream assembledOs = new FileOutputStream(assembledFile);
byte[] buf = new byte[100000];
try {
for (long chunkFrom : chunkStarts) {
File chunkFile = new File(dir, fileName + "." + chunkFrom + ".chunk");
InputStream is = new FileInputStream(chunkFile);
try {
while (true) {
int r = is.read(buf);
if (r == -1)
break;
if (r > 0)
assembledOs.write(buf, 0, r);
}
} finally {
is.close();
}
chunkFile.delete();
}
} finally {
assembledOs.close();
}
return assembledFile;
}
L'idea è quella di scrivere pezzi come file separati e da assemblare nel momento in cui tutti i file di blocchi hanno una lunghezza comune uguale alla lunghezza del file completo. Sul lato client è possibile definire le proprietà di utilizzo all'avvio del caricamento (è fatto qui per uploadId - ID univoco per ogni file). Questo uploadId è lo stesso per tutti i blocchi di un file. Qualsiasi domanda? Fammelo sapere.
[AGGIORNAMENTO] Esistono due dipendenze: https://commons.apache.org/proper/commons-fileupload/ e https://github.com/FasterXML/jackson.
Non dovrebbe essere contrassegnato con "javascript"? –
Vedere http://stackoverflow.com/q/31222657/2801559 – guest271314
le richieste di upload appartengono a una sessione lato server? – wero