I have a signed file uploader applet that works in Chrome but seems to hang when run in IE. In IE, I can successfully upload a file (or set of files) one time but the next time I try to upload another file, the browser freezes and I have to close the browser. It seems to be happening when I attempt to retrieve the outputstream of the HttpUrlConnection object. Here is my code:
public void upload(URL url, URL returnUrl, List<FileIconPanel> files) {
HttpURLConnection conn = null;
try {
conn = (HttpURLConnection) url.openConnection();
conn.setDoOutput(true);
conn.setDoInput(true);
conn.setUseCaches(false);
conn.setChunkedStreamingMode(1024);
HttpURLConnection.setFollowRedirects(false);
conn.setRequestProperty("content-type", "application/zip");
conn.setRequestMethod("POST");
//This zip output stream will server as our stream to the server and will zip each file while
// it sends it to the server.
ZipOutputStream out = new ZipOutputStream(conn.getOutputStream());
for (int i = 0; i < files.size(); i++) {
//For each file we will create a new entry in the ZIP archive and stream the file into that entry.
File f = (File) files.get(i).getFile();
ZipEntry entry = new ZipEntry(f.getName());
out.putNextEntry(entry);
InputStream in = new FileInputStream(f);
int read;
byte[] buf = new byte[1024];
while ((read = in.read(buf)) > 0) {
out.write(buf, 0, read);
}
out.closeEntry();
}
//Once we are done writing out our stream we will finish building the archive and close the stream.
out.finish();
out.close();
// Now that we have set all the connection parameters and prepared all
// the data we are ready to connect to the server.
conn.connect();
// read & parse the response
InputStream is = conn.getInputStream();
StringBuilder response = new StringBuilder();
byte[] respBuffer = new byte[4096];
while (is.read(respBuffer) >= 0) {
response.append(new String(respBuffer).trim());
}
is.close();
} catch (IOException ioE) {
ioE.printStackTrace();
logger.info("An unexpected exception has occurred. Contact your system administrator");
} catch (Exception e) {
e.printStackTrace();
logger.info("An unexpected exception has occurred. Contact your system administrator");
} finally {
//Once we are done we want to make sure to disconnect from the server.
if (conn != null) conn.disconnect();
}
}
I can see in the log files that it is freezing a this line:
ZipOutputStream out = new ZipOutputStream(conn.getOutputStream());
the second time I try to upload a file. This code also does work in IE under java 6. It has had this problem since I updated to the latest.
Is there something I'm leaving open that I need to make sure to close out before using the applet again? Been beating my head against this for the last two days. Sure hope someone can help...
I have an idea of what's going on but I don't know exactly the details of the what's causing the problem. I at least figured it out a workaround...I was using a jquery dialog box to display the applet. I was doing this on the fly so every time I open the dialog box, it was building the applet again. It's strange because I was in fact removing the div element that contained the applet every time the dialog box was closed so I would have thought that would ensure the old applet instance was destroyed as well. Chrome seems to be smart enough to destroy it and create a new one (or something to that effect) but IE has problems.
Related
I want to download a file from a Server into a client machine. But i want the file to be downloaded from a browser : I want the file to be saved at the Downloads Folder.
Im using the following code to download files.
public void descarga(String address, String localFileName) {
OutputStream out = null;
URLConnection conn = null;
InputStream in = null;
try {
// Get the URL
URL url = new URL(address);
// Open an output stream to the destination file on our local filesystem
out = new BufferedOutputStream(new FileOutputStream(localFileName));
conn = url.openConnection();
in = conn.getInputStream();
// Get the data
byte[] buffer = new byte[1024];
int numRead;
while ((numRead = in.read(buffer)) != -1) {
out.write(buffer, 0, numRead);
}
// Done! Just clean up and get out
} catch (Exception exception) {
exception.printStackTrace();
} finally {
try {
if (in != null) {
in.close();
}
if (out != null) {
out.close();
}
} catch (IOException ioe) {
// Shouldn't happen, maybe add some logging here if you are not
// fooling around ;)
}
}
It works but unless i specify the absolute path it does not download the file, therefore is useless to use from different clients with different browsers, because the webpage does not even prompts the message that lets the user know that a file is being downloaded. What can i add to get that to work?
Thanks
After almost 2 workdays of Googling and trying several different possibilities I found throughout the web, I'm asking this question here, hoping that I might finally get an answer.
First of all, here's what I want to do:
I'm developing a client and a server application with the purpose of exchanging a lot of large files between multiple clients on a single server. The client is developed in pure Java (JDK 1.6), while the web application is done in Grails (2.0.0).
As the purpose of the client is to allow users to exchange a lot of large files (usually about 2GB each), I have to implement it in a way, so that the uploads are resumable, i.e. the users are able to stop and resume uploads at any time.
Here's what I did so far:
I actually managed to do what I wanted to do and stream large files to the server while still being able to pause and resume uploads using raw sockets. I would send a regular request to the server (using Apache's HttpClient library) to get the server to send me a port that was free for me to use, then open a ServerSocket on the server and connect to that particular socket from the client.
Here's the problem with that:
Actually, there are at least two problems with that:
I open those ports myself, so I have to manage open and used ports myself. This is quite error-prone.
I actually circumvent Grails' ability to manage a huge amount of (concurrent) connections.
Finally, here's what I'm supposed to do now and the problem:
As the problems I mentioned above are unacceptable, I am now supposed to use Java's URLConnection/HttpURLConnection classes, while still sticking to Grails.
Connecting to the server and sending simple requests is no problem at all, everything worked fine. The problems started when I tried to use the streams (the connection's OutputStream in the client and the request's InputStream in the server). Opening the client's OutputStream and writing data to it is as easy as it gets. But reading from the request's InputStream seems impossible to me, as that stream is always empty, as it seems.
Example Code
Here's an example of the server side (Groovy controller):
def test() {
InputStream inStream = request.inputStream
if(inStream != null) {
int read = 0;
byte[] buffer = new byte[4096];
long total = 0;
println "Start reading"
while((read = inStream.read(buffer)) != -1) {
println "Read " + read + " bytes from input stream buffer" //<-- this is NEVER called
}
println "Reading finished"
println "Read a total of " + total + " bytes" // <-- 'total' will always be 0 (zero)
} else {
println "Input Stream is null" // <-- This is NEVER called
}
}
This is what I did on the client side (Java class):
public void connect() {
final URL url = new URL("myserveraddress");
final byte[] message = "someMessage".getBytes(); // Any byte[] - will be a file one day
HttpURLConnection connection = url.openConnection();
connection.setRequestMethod("GET"); // other methods - same result
// Write message
DataOutputStream out = new DataOutputStream(connection.getOutputStream());
out.writeBytes(message);
out.flush();
out.close();
// Actually connect
connection.connect(); // is this placed correctly?
// Get response
BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
String line = null;
while((line = in.readLine()) != null) {
System.out.println(line); // Prints the whole server response as expected
}
in.close();
}
As I mentioned, the problem is that request.inputStream always yields an empty InputStream, so I am never able to read anything from it (of course). But as that is exactly what I'm trying to do (so I can stream the file to be uploaded to the server, read from the InputStream and save it to a file), this is rather disappointing.
I tried different HTTP methods, different data payloads, and also rearranged the code over and over again, but did not seem to be able to solve the problem.
What I hope to find
I hope to find a solution to my problem, of course. Anything is highly appreciated: hints, code snippets, library suggestions and so on. Maybe I'm even having it all wrong and need to go in a totally different direction.
So, how can I implement resumable file uploads for rather large (binary) files from a Java client to a Grails web application without manually opening ports on the server side?
HTTP GET method have special headers for range retrieval: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35 It's used by most downloaders to do resumable download from server.
As I understand, there are no standard practice for using this headers for POST/PUT request, but it's up to you, right? You can make pretty standard Grails controller, that will accept standard http upload, with header like Range: bytes=500-999. And controller should put this 500 uploaded bytes from client into file, starting at position 500
At this case you don't need to open any socket, and make own protocols, etc.
P.S. 500 bytes is just a example, probably you're using much bigger parts.
Client Side Java Programming:
public class NonFormFileUploader {
static final String UPLOAD_URL= "http://localhost:8080/v2/mobileApp/fileUploadForEOL";
static final int BUFFER_SIZE = 4096;
public static void main(String[] args) throws IOException {
// takes file path from first program's argument
String filePath = "G:/study/GettingStartedwithGrailsFinalInfoQ.pdf";
File uploadFile = new File(filePath);
System.out.println("File to upload: " + filePath);
// creates a HTTP connection
URL url = new URL(UPLOAD_URL);
HttpURLConnection httpConn = (HttpURLConnection) url.openConnection();
httpConn.setDoOutput(true);
httpConn.setRequestMethod("POST");
// sets file name as a HTTP header
httpConn.setRequestProperty("fileName", uploadFile.getName());
// opens output stream of the HTTP connection for writing data
OutputStream outputStream = httpConn.getOutputStream();
// Opens input stream of the file for reading data
FileInputStream inputStream = new FileInputStream(uploadFile);
byte[] buffer = new byte[BUFFER_SIZE];
int bytesRead = -1;
while ((bytesRead = inputStream.read(buffer)) != -1) {
System.out.println("bytesRead:"+bytesRead);
outputStream.write(buffer, 0, bytesRead);
outputStream.flush();
}
System.out.println("Data was written.");
outputStream.flush();
outputStream.close();
inputStream.close();
int responseCode = httpConn.getResponseCode();
if (responseCode == HttpURLConnection.HTTP_OK) {
// reads server's response
BufferedReader reader = new BufferedReader(new InputStreamReader(
httpConn.getInputStream()));
String response = reader.readLine();
System.out.println("Server's response: " + response);
} else {
System.out.println("Server returned non-OK code: " + responseCode);
}
}
}
Server Side Grails Programme:
Inside the controller:
def fileUploadForEOL(){
def result
try{
result = mobileAppService.fileUploadForEOL(request);
}catch(Exception e){
log.error "Exception in fileUploadForEOL service",e
}
render result as JSON
}
Inside the Service Class:
def fileUploadForEOL(request){
def status = false;
int code = 500
def map = [:]
try{
String fileName = request.getHeader("fileName");
File saveFile = new File(SAVE_DIR + fileName);
System.out.println("===== Begin headers =====");
Enumeration<String> names = request.getHeaderNames();
while (names.hasMoreElements()) {
String headerName = names.nextElement();
System.out.println(headerName + " = " + request.getHeader(headerName));
}
System.out.println("===== End headers =====\n");
// opens input stream of the request for reading data
InputStream inputStream = request.getInputStream();
// opens an output stream for writing file
FileOutputStream outputStream = new FileOutputStream(saveFile);
byte[] buffer = new byte[BUFFER_SIZE];
int bytesRead = inputStream.read(buffer);
long count = bytesRead
while(bytesRead != -1) {
outputStream.write(buffer, 0, bytesRead);
bytesRead = inputStream.read(buffer);
count += bytesRead
}
println "count:"+count
System.out.println("Data received.");
outputStream.close();
inputStream.close();
System.out.println("File written to: " + saveFile.getAbsolutePath());
code = 200
}catch(Exception e){
mLogger.log(java.util.logging.Level.SEVERE,"Exception in fileUploadForEOL",e);
}finally{
map <<["code":code]
}
return map
}
I have tried with above code it is worked for me(only for file size 3 to 4MB, but for small size files some bytes of code missing or not even coming but in request header content-length is coming, not sure why it is happening.)
I'm trying to upload images to External MS SQL database using android phone. I'm using Java HttpClient to send array of bytes to web server or web page. I don't know how I should approach this. The web page should be in ASP.net. I'm fairly new to ASP.Net. I did intensive research on how to read in a byte array using ASP.Net and still don't have an answer. I want my webpage or server to read in the bytes and store them into database.
Below is my Java function (it is not tested yet since I don't have a way to read bytes yet) that I want to use to send the bytes. But I have no idea how to read them in on website side. Any suggestions would be appreciated. If you guys see that I'm doing something wrong also it would be appreciated if you let me know and tell me how I should fix it. Please be specific since I'm really new to this and don't really know much about web pages. Thanks.
private void sendImagesToServer() throws Exception
{
ImageItem image;
HttpURLConnection conn = null;
ImageIterator iterator;
DataOutputStream dos;
byte[] byteArray;
iterator = new ImageIterator(imageAdapter);
String uploadUrl;
while(iterator.hasNext())
{
image = iterator.getNext();
Uri uri = Uri.withAppendedPath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, Integer.toString(image.id));
Bitmap bmp=BitmapFactory.decodeStream(getContentResolver().openInputStream(uri));
ByteArrayOutputStream stream = new ByteArrayOutputStream();
bmp.compress(Bitmap.CompressFormat.JPEG, 100, stream);
byteArray = stream.toByteArray();
uploadUrl = "http://localhost:63776/SQLScript.aspx";
// Send request
try {
// Configure connection
URL url = new URL(uploadUrl);
conn = (HttpURLConnection) url.openConnection();
conn.setDoInput(true);
conn.setDoOutput(true);
conn.setUseCaches(false);
conn.setRequestMethod("PUT");
conn.setRequestProperty("Connection", "Keep-Alive");
dos = new DataOutputStream(conn.getOutputStream());
dos.write(byteArray, 0, byteArray.length);
dos.flush();
dos.close();
// Read response
try {
if (conn.getResponseCode() == 200) {
Toast.makeText(this,"Yay, We Got 200 as Response Code",Toast.LENGTH_SHORT).show();
}
} catch (IOException ioex) {
ioex.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
} finally{
}
}
}
If you've verified the bytes are getting out of the Java fine, check this question, it may have what you need.
Read Http Request into Byte array
As far as getting it into a database, you could save files in a binary database (different MSSQL setup) or convert to strings and back again as necessary.
i am writing a small android application which requires some data which is stored on my web server. The file is a .txt file curretly less than 1 MB. Is it advisable to set up a ftp server to get the data or can i just use a http get method to get the contents on a file. If i am using a http get can someone please tell me the java code required for this operation.
This is out of my head (so an error could have sneaked in):
URL url = new URL("http://www.yourserver.com/some/path");
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
try {
InputStream in = new BufferedInputStream(urlConnection.getInputStream());
FileOutputStream out = new FileutputStream("/path/to/your/output/file");
byte[] buffer = new byte[16384];
int len;
while((len = in.read(buffer)) != -1){
out.write(buffer, 0, len);
}
finally {
urlConnection.disconnect();
}
I have this little piece of code below which uploads a file in java, the code functions correctly however it hangs for a long time when opening the output stream.
// open file to upload
InputStream filein = new FileInputStream("/path/to/file.txt");
// connect to server
URL url = new URL("ftp://user:pass#host/dir/file.txt");
URLConnection urlConn = url.openConnection();
urlConn.setDoOutput(true);
// write file
// HANGS FROM HERE
OutputStream ftpout = urlConn.getOutputStream();
// TO HERE for about 22 seconds
byte[] data = new byte[1024];
int len = 0;
while((len = filein.read(data)) > 0) {
ftpout.write(data,0, len);
}
// close file
filein .close();
ftpout.close();
In this example the URLConnection.getOutputStream() method hangs for about 22 seconds before continuing as normal, the file is successfully uploaded. The file is only 4 bytes in this case, just a text file with the word 'test' in it and the code hangs before the upload commences so its not because its taking time to upload the file.
This is only happening when connecting to one server, when I try a different server its as fast I could hope for which leads me to think it is a server configuration issue in which case this question may be more suited to server fault, however if I upload from an FTP client (in my case FileZilla) it works fine so it could be there is something I can do with the code to fix this.
Any ideas?
I have solved the problem by switching to use the Commons Net FTPClient which does not apear to have the same problems which changes the code to this below.
InputStream filein = new FileInputStream(new File("/path/to/file.txt"));
// create url
FTPClient ftp = new FTPClient();
ftp.connect(host);
ftp.login(user, pass);
int reply = ftp.getReplyCode();
if(!FTPReply.isPositiveCompletion(reply)) {
ftp.disconnect();
System.err.println("FTP server refused connection.");
return;
}
OutputStream ftpout = ftp.appendFileStream("text.txt");
// write file
byte[] data = new byte[1024];
int len = 0;
while((len = filein.read(data)) > 0) {
ftpout.write(data,0, len);
}
filein.close();
ftpout.close();
ftp.logout();