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Download the byte array as a original file in AngularJS from server

I have the below requirement,
Java server will send the below details by reading the file from server (it can be pdf, doc or image)
Java code:
public static byte[] downloadFileAsStream(String fileName) throws IOException, MalformedURLException
File file = new File(fileName);
if (!file.exists()) {
// File not found
return null;
}
try {
InputStream inputStream = new BufferedInputStream(new FileInputStream(file));
return readFileAsByte(file.getAbsolutePath());
} catch (FileNotFoundException ex) {
ex.printStackTrace();
}
return null;
}
private static byte[] readFileAsByte(String filePath) {
try {
Path path = Paths.get(filePath);
return Files.readAllBytes(path);
} catch (IOException ex) {
ex.printStackTrace();
}
return new byte[0];
}
server will return the file as byte array, then this needs to be converted as the original file AngularJS and download

You need to add the response header in server side like below.
response.setHeader("Content-Type", "application/pdf");
response.setHeader("Content-Disposition", "attachment; filename=sample.pdf");

The following code may be used to create a file on client side based on the response from server:
$http.post("<SERVER_URL>", "<PARAMS_IF_ANY>", {
responseType:'arraybuffer'
}).success(function(data, status, headers) {
var contentType = headers["content-type"] || "application/octet-stream";
var urlCreator = window.URL || window.webkitURL || window.mozURL || window.msURL;
if (urlCreator) {
var blob = new Blob([data], { type: contentType });
var url = urlCreator.createObjectURL(blob);
var a = document.createElement("a");
document.body.appendChild(a);
a.style = "display: none";
a.href = url;
a.download = "download.pdf"; //you may assign this value from header as well
a.click();
window.URL.revokeObjectURL(url);
}
}

How to clean up temporary file after response in JAX-RS REST Service?

I am returning a temporary file from my JAX-RS REST Service like below:
#GET
#Produces(MediaType.APPLICATION_OCTET_STREAM)
public Response getFile() {
File file = ... // create a temporary file
return Response.ok(file, MediaType.APPLICATION_OCTET_STREAM)
.header("Content-Disposition", "attachment; filename=\"" + file.getName() + "\"" ) //optional
.build();
}
What is the correct way of removing this temporary file after the response has been processed? Is the JAX-RS implementation (like Jersey) supposed to do this automatically?

You can pass an instance of StreamingOutput that copies the content of the source file to the client output and eventually deletes the file.
final Path path = getTheFile().toPath();
final StreamingOutput output = o -> {
final long copied = Files.copy(path, o);
final boolean deleted = Files.deleteIfExists(path);
};
return Response.ok(output).build();
final File file = getTheFile();
return Response.ok((StreamingOutput) output -> {
final long copied = Files.copy(file.toPath(), output);
final boolean deleted = file.delete();
}).build();

The example on https://dzone.com/articles/jax-rs-streaming-response looks more helpful than the brief reply from Jin Kwon.
Here is an example:
public Response getDocumentForMachine(#PathParam("custno") String custno, #PathParam("machineno") String machineno,
#PathParam("documentno") String documentno, #QueryParam("language") #DefaultValue("de") String language)
throws Exception {
log.info(String.format("Get document. mnr=%s, docno=%s, lang=%s", machineno, documentno, language));
File file = new DocFileHelper(request).getDocumentForMachine(machineno, documentno, language);
if (file == null) {
log.error("File not found");
return Response .status(404)
.build();
}
StreamingOutput stream = new StreamingOutput() {
#Override
public void write(OutputStream out) throws IOException, WebApplicationException {
log.info("Stream file: " + file);
try (FileInputStream inp = new FileInputStream(file)) {
byte[] buff = new byte[1024];
int len = 0;
while ((len = inp.read(buff)) >= 0) {
out.write(buff, 0, len);
}
out.flush();
} catch (Exception e) {
log.log(Level.ERROR, "Stream file failed", e);
throw new IOException("Stream error: " + e.getMessage());
} finally {
log.info("Remove stream file: " + file);
file.delete();
}
}
};
return Response .ok(stream)
.build();
}

How to download file in browser using spring mvc?

I have file on the server & that I want to download on my machine using browser. But I am not getting an option from browser to download the file.
My code is
JSP
<div id="jqgrid">
<table id="grid"></table>
<div id="pager"></div>
</div>
JS
jq("#grid").jqGrid({
....
onCellSelect: function(rowid, index, contents, event) {
...
var fileName = jQuery("#grid").jqGrid('getCell',rowid,'fileName');
$scope.downloadFile(fileName);
}
});
$scope.downloadFile = function(fileName) {
$http({
url: "logreport/downLoadFile",
method: "GET",
params: {"fileName": fileName}
});
};
Controller
#RequestMapping(value = "/downLoadFile", method = RequestMethod.GET)
public void downLoadFile(HttpServletRequest request, HttpServletResponse response) {
try {
String fileName = request.getParameter("fileName");
File file = new File(filePath +"//"+fileName);
InputStream in = new BufferedInputStream(new FileInputStream(file));
response.setContentType("application/xlsx");
response.setHeader("Content-Disposition", "attachment; filename="+fileName+".xlsx");
ServletOutputStream out = response.getOutputStream();
IOUtils.copy(in, out);
response.flushBuffer();
} catch (Exception e) {
e.printStackTrace();
}
}
I am not getting any exception but not sure why browser dialog is not opening to download the file. Also where is it exactly downloading the file?

#SotiriosDelimanolis was right. File download is not possible using ajax request.
Simply use 'window.location'.
$scope.downloadFile = function(fileName) {
window.location.href = 'logreport/downLoadFile?fileName=asdad1';
};

I didn't have enough credit to give a comment so wiritting here.. Thanks user1298426. I was strugling like anything for this. I was trying with AJAX. With window.location.href, I can download file in browser...
MY javascript code is as follows:
jQuery('#exportToZip').click(function() {
window.location.href = '*****';
});
*****: is the url mapping that I have in controller.
#RequestMapping(value = "/****")
#ResponseBody
public void downloadRequesthandler(HttpServletRequest request,HttpServletResponse response) {
String status;
try {
filedownloader.doGet(request, response);
} catch (ServletException e) {
status="servlet Exception occured";
e.printStackTrace();
} catch (IOException e) {
status="IO Exception occured";
e.printStackTrace();
}
//return status;
}
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
ServletContext context = request.getServletContext();
// construct the complete absolute path of the file
File downloadFile = new File(filePath);
System.out.println("downloadFile path: "+ filePath);
FileInputStream inputStream = new FileInputStream(downloadFile);
// get MIME type of the file
String mimeType = context.getMimeType(fullPath);
if (mimeType == null) {
// set to binary type if MIME mapping not found
mimeType = "application/octet-stream";
}
System.out.println("MIME type: " + mimeType);
response.setContentLength((int) downloadFile.length());
// set headers for the response
String headerKey = "Content-Disposition";
String headerValue = String.format("attachment; filename=\"%s\"",downloadFile.getName());
response.setHeader(headerKey, headerValue);
OutputStream outStream = response.getOutputStream();
byte[] buffer = new byte[BUFFER_SIZE];
System.out.println("buffer: "+ buffer.length);
int bytesRead = -1;
// write bytes read from the input stream into the output stream
//be carefull in this step. "writebeyondcontentlength" and "response already committed" error is very common here
while ((bytesRead = inputStream.read(buffer))!=-1 ) {
outStream.write(buffer, 0, bytesRead);
}
inputStream.close();
outStream.close();
}
Trying to download file with ajax is a blunder....
cheers......

Instead of using IOUtils copy method
ServletOutputStream out = response.getOutputStream();
IOUtils.copy(in, out);
You can use following :
ServletOutputStream out = response.getOutputStream();
byte[] bytes = IOUtils.toByteArray(in);
out.write(bytes);
out.close();
out.flush();
Hope this will work.

Upload file using HTTP Post multipart - 4Sharing API J2ME

I'm currently developing a J2ME app. I'm having problems with file uploading. I dont seem to know what part of my code is wrong. Here is my code:
public void UploadImage(long newFileId, String url, String bytes){
HttpConnection conn = null;
OutputStream os = null;
InputStream s = null;
StringBuffer responseString = new StringBuffer();
try
{
System.out.println(System.getProperty("HTTPClient.dontChunkRequests"));
conn.setRequestMethod(HttpConnection.POST);
conn = (HttpConnection)Connector.open(url);
conn.setRequestProperty("resumableFileId", ""+newFileId);
conn.setRequestProperty("resumableFirstByte", ""+0);
conn.setRequestProperty("FilePart", bytes);
// Read
s = conn.openInputStream();
int ch, i = 0, maxSize = 16384;
while(((ch = s.read())!= -1 ) & (i++ < maxSize))
{
responseString.append((char) ch);
}
conn.close();
System.out.println(responseString.toString());
String res = uploadFinishFile(newFileId, bytes);
if(res.length()>0)
System.out.println("File uploaded.");
else
System.out.println("Upload failed: "+res);
}
catch (Exception e)
{
System.out.println(e.toString());
}
}
This is the java code that im trying to convert to j2me:
try {
HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost(url);
MultipartEntity me = new MultipartEntity();
StringBody rfid = new StringBody("" + newFileId);
StringBody rfb = new StringBody("" + 0);
InputStreamBody isb = new InputStreamBody(new BufferedInputStream(new FileInputStream(f)), "FilePart");
me.addPart("resumableFileId", rfid);
me.addPart("resumableFirstByte", rfb);
me.addPart("FilePart", isb);
post.setEntity(me);
HttpResponse resp = client.execute(post);
HttpEntity resEnt = resp.getEntity();
String res = da.uploadFinishFile(login, password, newFileId, DigestUtils.md5Hex(new FileInputStream(f)));
if(res.isEmpty())
System.out.println("File uploaded.");
else
System.out.println("Upload failed: "+res);
} catch (Exception ex) {
System.out.println("Upload failed: "+ex.getMessage());
}

You are uploading the file passing the parameters as HTTP headers, instead of sending the image in the HTTP message body using multipart file upload, compatible with the code you're converting.
Take a look at HTTP Post multipart file upload in Java ME. You can use the HttpMultipartRequest class and change your code to:
Hashtable params = new Hashtable();
params.put("resumableFileId", "" + newFileId);
params.put("resumableFirstByte", "" + 0);
HttpMultipartRequest req = new HttpMultipartRequest(
url,
params,
"FilePart", "original_filename.png", "image/png", isb.getBytes()
);
byte[] response = req.send();

How to return back or call signed applet's method from server side controller?

My download scenario is: when i click on download link on jsp it calls signed applet method with file's id, from applet I call server side method by passing that id. I can get that file at server side but I want to return/pass that file back to my applet function.
My question is how to return back or pass downloaded file to my applet?
Or How can I set a file to response object at server side that can be useful at applet?
My Signed Applet :
private static void downloadEncryptedFile(String uuid) throws HttpException, IOException {
String uri = "http://localhost:8080/encryptFileDownload.works?uuid="+uuid;
HttpClient client = new HttpClient();
PostMethod postMethod = new PostMethod(uri);
postMethod.setRequestHeader("Content-type", "text/xml; charset=ISO-8859-1");
client.executeMethod(postMethod);
postMethod.releaseConnection();
}
My Server side function:
#RequestMapping(value = "/encryptFileDownload/{uuid}.works", method = RequestMethod.POST)
public String downloadEncryptFile(#PathVariable("uuid") String uuid, HttpSession session, HttpServletResponse response) {
try {
if (StringUtils.isNotEmpty(uuid)) {
LOG.info("-----UUID----");
Node node = contentRetrieveService.getByNodeId(uuid);
Node resource = node.getNode("jcr:content");
response.setContentType("application/octet-stream");
response.setHeader("Content-Disposition", "attachment; filename=\"" + node.getName() + "\"");
InputStream in = resource.getProperty("jcr:data").getBinary().getStream();
ServletOutputStream outs = response.getOutputStream();
int i = 0;
while ((i = in.read()) != -1) {
outs.write(i);
}
outs.flush();
outs.close();
in.close();
LOG.info("File Downloaded");
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}

I got the solution; I just wanted to pass a file id download it and return that file back to my applet, hence I have made changes in my code as:
My Applet:
try {
URL urlServlet = new URL("uri for your servlet");
URLConnection con = urlServlet.openConnection();
con.setDoInput(true);
con.setDoOutput(true);
con.setUseCaches(false);
con.setRequestProperty(
"Content-Type",
"application/x-java-serialized-object");
// send data to the servlet
OutputStream outstream = con.getOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(outstream);
oos.writeObject(uuid);
oos.flush();
oos.close();
// receive result from servlet
InputStream instr = con.getInputStream();
ObjectInputStream inputFromServlet = new ObjectInputStream(instr);
String name = con.getHeaderField("filename");
File fi = new File(name);
int i = 0;
while ((i = inputFromServlet.read()) != -1) {
System.out.println(inputFromServlet.readLine());
}
inputFromServlet.close();
instr.close();
} catch (Exception ex) {
ex.printStackTrace();
}
Server side Function just replace with this:
OutputStream outs = response.getOutputStream();
outputToApplet = new ObjectOutputStream(outs);
int i = 0;
while ((i = in.read()) != -1) {
outputToApplet.write(i);
}