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How can i zip multiple pdf files in Primefaces?

I want to zip multiple pdf files which are selected in the data-table and let the user download them.
Here is XHTML;
<p:commandLink id="print_orders"
value="Print Selected Orders" ajax="false"
onclick="PrimeFaces.monitorDownload(startPrint, stopPrint);"
styleClass="button button--ujarak button--border-thin button--text-medium download"
style="text-align: center; float:none; margin: 0px auto 0px auto; padding: 0.05em 0.1em;" >
<p:fileDownload value="#{printOrdersManagedBeanSAP.printsAction()}" />
</p:commandLink>
Let me clarify managedbean side;
purchaseOrder object includes PO_NUMBER() I generate pdf document (pdfDoc) as ByteArrayOutputStream from SAP with PO_NUMBER(). With for loop I tried to produce zip file includes pdf documents as much as the selected column. By the way I'm not sure I did it right.
With "return (StreamedContent) output;" code block I tried to return zip file but I get "java.util.zip.ZipOutputStream cannot be cast to org.primefaces.model.StreamedContent" exception. I tried to convert ZipOutputStream to StreamedContent because of <p:fileDownload> Primefaces tag.
Can you help me with how to fix this problem?
public StreamedContent printsAction()
{
if(!termsAgreed)
RequestContext.getCurrentInstance().execute("PF('warningDialog').show();");
else
{
if (getSelectedPurchaseOrders() != null && !getSelectedPurchaseOrders().isEmpty()) {
try
{
FileOutputStream zipFile = new FileOutputStream(new File("PO_Reports.zip"));
ZipOutputStream output = new ZipOutputStream(zipFile);
for (PurchaseOrderSAP purchaseOrder : getSelectedPurchaseOrders()) {
ByteArrayOutputStream pdfDoc = purchaseOrderSAPService.printOrder(selectedPurchaseOrder.getPO_NUMBER());
ZipEntry zipEntry = new ZipEntry(purchaseOrder.getPO_NUMBER());
output.putNextEntry(zipEntry);
InputStream targetStream = new ByteArrayInputStream(pdfDoc.toByteArray());
IOUtils.copy(targetStream, output);
output.closeEntry();
}
output.finish();
output.close();
return (StreamedContent) output;
}
catch(Exception ex)
{
System.out.println("error when generating...");
ex.printStackTrace();
}
}
}
return null;
}

You cannot simply cast a ZipOutputStream to StreamedContent as they don't have a parent child relation. See How can I cast objects that don't inherit each other?.
You should convert your InputStream (not the output stream) to streamed content. See for example https://www.primefaces.org/showcase/ui/file/download.xhtml
So, you need to do something like:
DefaultStreamedContent.builder()
.name("PO_Reports.zip")
.contentType("application/zip")
.stream(() -> yourInputStream)
.build();

I found solutions to these problems. Maybe this solution will help someone else. I would be grateful for any contribution on the new solution.
public StreamedContent printsAction() {
ByteArrayInputStream bis = null;
InputStream stream = null;
if (!termsAgreed) {
RequestContext.getCurrentInstance().execute("PF('warningDialog').show();");
} else {
if (getSelectedPurchaseOrders() != null && !getSelectedPurchaseOrders().isEmpty()) {
try {
if (zipBytes() != null) {
bis = new ByteArrayInputStream(zipBytes()); // Firstly I zip every PDF doc with zipBytes() method
stream = bis;
file = new DefaultStreamedContent(stream, "application/zip", "PO_Reports.zip",StandardCharsets.UTF_8.name());
return file;
} else {
return null;
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (bis != null) {
bis.close();
}
if (stream != null) {
stream.close();
}
} catch (Exception e2) {
e2.printStackTrace();
}
}
} else {
return null;
}
}
return null;
}
private byte[] zipBytes() {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ByteArrayOutputStream pdfDoc = new ByteArrayOutputStream();
ZipOutputStream zos = new ZipOutputStream(baos);
DataInputStream pdfDocIs = null;
byte[] result = null;
try {
for(PurchaseOrderSAP purchaseOrder : getSelectedPurchaseOrders()) {
pdfDoc = purchaseOrderSAPService.printOrder(purchaseOrder.getPO_NUMBER()); // PDF document comes from SAP as ByteArrayOutputStream
pdfDocIs = new DataInputStream(new ByteArrayInputStream(pdfDoc.toByteArray()));
ZipEntry zipEntry = new ZipEntry("PO_Report_" + purchaseOrder.getPO_NUMBER() + ".pdf");
zos.putNextEntry(zipEntry);
zos.write(toByteArray(pdfDocIs)); // Secondly in order to zip PDF doc i convert it to Byte Array with toByteArray method
}
zos.close();
result = baos.toByteArray();
} catch (Exception e) {
e.printStackTrace();
}
finally {
try {
if (baos != null) {
baos.close();
}
if (pdfDoc != null) {
pdfDoc.close();
}
if (zos != null) {
zos.close();
}
if (pdfDocIs != null) {
pdfDocIs.close();
}
} catch (Exception e2) {
e2.printStackTrace();
}
}
return result;
}
public static byte[] toByteArray(InputStream in) {
ByteArrayOutputStream os = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
byte[] result = null;
int len;
// read bytes from the input stream and store them in buffer
try {
while ((len = in.read(buffer)) != -1) {
// write bytes from the buffer into output stream
os.write(buffer, 0, len);
}
result = os.toByteArray();
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (os != null) {
os.close();
}
} catch (Exception e2) {
e2.printStackTrace();
}
}
return result;
}

Java FileOutputStream Created file Not unlocking

Currently am facing a problem with FileOutputStream in my code used FileOutputStream for creating file in my disk .Once file created there is no way for opening , deleting or moving file from its location ,getting error message already locked by other user When stopped web server it working properly .how can i solve this issue.
private void writeToFile(InputStream uploadedInputStream,
String uploadedFileLocation) {
try {
OutputStream out = new FileOutputStream(new File(
uploadedFileLocation));
int read = 0;
byte[] bytes = new byte[1024];
out = new FileOutputStream(new File(uploadedFileLocation));
while ((read = uploadedInputStream.read(bytes)) != -1) {
out.write(bytes, 0, read);
}
out.flush();
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}

You are creating two instances of FileOutputStream and assigning both to out, but only closing one.
Remove the second out = new FileOutputStream(new File(uploadedFileLocation));.
Also, you should consider using a try-with-resources block
private void writeToFile(InputStream uploadedInputStream,
String uploadedFileLocation) {
try (OutputStream out = new FileOutputStream(new File(uploadedFileLocation))) {
int read = 0;
byte[] bytes = new byte[1024];
while ((read = uploadedInputStream.read(bytes)) != -1) {
out.write(bytes, 0, read);
}
} catch (IOException e) {
e.printStackTrace();
}
}
or finally block to ensure that the streams are closed
private void writeToFile(InputStream uploadedInputStream,
String uploadedFileLocation) {
OutputStream out = null;
try {
out = new FileOutputStream(new File(uploadedFileLocation))
int read = 0;
byte[] bytes = new byte[1024];
while ((read = uploadedInputStream.read(bytes)) != -1) {
out.write(bytes, 0, read);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (out != null) {
try {
out.close();
} catch (IOException exp) {
}
}
}
}
See The try-with-resources Statement for more details

reading deflated data from the stream using inflater and InflaterInputStream

I'm trying to send a deflated string over http, when I use compression and decompression on the server side, without using streams, it's ok but when I write it to stream like this:
byte[] deflatedData = mtext.getByte();
try {
t.sendResponseHeaders(200,deflatedData.length);
} catch (IOException e1) {
display(e1);
e1.printStackTrace();
if(closeafter){
t.close();
}
return;
}
DeflaterOutputStream os = new DeflaterOutputStream(t.getResponseBody());
try {
os.write(deflatedData ,0,deflatedData .length);
} catch (IOException e1) {
mByte = null;
display(e1);
if(closeafter){
t.close();
}
return;
}
os.flush();
os.close();
and read from client side like this:
InflaterInputStream ini = new
InflaterInputStream(response.body().byteStream());
ByteArrayOutputStream bout =new ByteArrayOutputStream(512);
int b;
while ((b = ini.read()) != -1) {
bout.write(b);
}
ini.close();
bout.close();
String s=new String(bout.toByteArray());
android decompresses like this:
public static byte[] decompress(byte[] data) throws IOException, DataFormatException{
Inflater inflater = new Inflater();
inflater.setInput(data);
ByteArrayOutputStream outputStream = new ByteArrayOutputStream(data.length);
byte[] buffer = new byte[1024];
while (!inflater.finished()) {
int count = inflater.inflate(buffer);
outputStream.write(buffer, 0, count);
}
byte[] output = outputStream.toByteArray();
outputStream.close();
inflater.end();
return output;
}
so I get the following exception:
java.util.zip.DataFormatException: data error
Where am I going wrong?

The sending part was totally ok , The answer was to Use InflaterInputStream Directly from the input stream , like this:
public static String ReadDeflatedData(InputStream input){
InflaterInputStream in = new InflaterInputStream(input, new Inflater());
int bytesRead=0;
StringBuilder sb = new StringBuilder();
byte[] contents = null;
try {
contents = new byte[in.available()];
} catch (IOException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
}
try {
while( (bytesRead = in.read(contents)) != -1){
sb.append(new String(contents, 0, bytesRead));
}
} catch (IOException e) {
System.out.println(e.toString());
e.printStackTrace();
}
try {
return new String(sb.toString().getBytes(),"UTF-8");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}

FileInputStream unmarshalling, but HttpInputStream won't in Java

I can marhsall XML from a file when I read it from disk, but when I download it via the web I get this error.
[org.xml.sax.SAXParseException; lineNumber: 1; columnNumber: 1; Premature end of file.]
at javax.xml.bind.helpers.AbstractUnmarshallerImpl.createUnmarshalException
I assume the web input stream contains additional information or something?
Works
InputStream inputStream = null;
try {
inputStream = new FileInputStream(filePath);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
Doesnt Work
InputStream inputStream = null;
try {
inputStream = new URL(url).openStream();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
BulkDataRecordType bulkDataRecordType = getObjectFromXml(inputStream);
In another class
public BulkDataRecordType getObjectFromXml(InputStream inputStream)
{
try {
JAXBContext jc = JAXBContext.newInstance(BulkDataRecordType.class);
Unmarshaller unmarshaller = jc.createUnmarshaller();
bulkDataRecordType = (BulkDataRecordType) unmarshaller.unmarshal(inputStream);
} catch (JAXBException e1) {
e1.printStackTrace();
}

I am first checking the checksum of the string. Once I commented this out it worked. I found a solution to create two new streams and it worked. If you have a better solution let me know.
public byte[] getCheckSumFromFile(InputStream inputStream)
{
MessageDigest md = null;
try {
md = MessageDigest.getInstance("MD5");
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
return null;
}
InputStream is = null;
try {
is = new DigestInputStream(inputStream, md);
}
finally {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
return md.digest();
}
Create Two Streams From Original
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
try {
byte[] buffer = new byte[1024];
int len;
while ((len = inputStream.read(buffer)) > -1 ) {
byteArrayOutputStream.write(buffer, 0, len);
}
byteArrayOutputStream.flush();
} catch (IOException e1) {
e1.printStackTrace();
}
inputStream = new ByteArrayInputStream(byteArrayOutputStream.toByteArray());
// Get check sum of downloaded file
byte[] fileCheckSum = getCheckSumFromFile(new ByteArrayInputStream(byteArrayOutputStream.toByteArray()));

Send a stop message in a socket

I want a efficient and a fast way of sending a stop message in a socket.
I have a method that send files from one pc to another. All of the files from the sender appear on the receiver's PC. However all of the data is being written to the first file (only). The other files exist, but are empty. This happen because the receiver method doesn't know when to start writing to the next file.
Sender
public static void sendFile (final Socket sock, File source)
{
FileInputStream fileIn = null;
try
{
//Read bytes from the source file
fileIn = new FileInputStream(source);
//Write bytes to the receive
//No need to use a buffered class, we make our own buffer.
OutputStream netOut = sock.getOutputStream();
byte[] buffer = new byte[BUFFER_SIZE];
int read;
while ((read = fileIn.read(buffer)) != -1)
{
netOut.write(buffer, 0, read);
netOut.flush ();
}
//Send some stop message here
}
catch (Exception e)
{
e.printStackTrace ();
}
finally
{
if (fileIn != null)
{
try
{
fileIn.close ();
}
catch (IOException e)
{
e.printStackTrace ();
}
}
}
}
//Send files via socket
public static void sendFile (final Socket sock, File[] source)
{
for (int i = 0; i < source.length; i++)
sendFile (sock, source[i]);
}
Receiver:
public static void receiveFile (final Socket sock, File destination)
{
BufferedOutputStream out = null;
try
{
//Receive data from socket
InputStream clientInputStream = sock.getInputStream();
//Write bytes to a file
out = new BufferedOutputStream (new FileOutputStream (destination));
byte[] buffer = new byte[BUFFER_SIZE];
int read;
while (true)
{
read = clientInputStream.read(buffer);
out.write(buffer, 0, read);
out.flush ();
}
}
catch (IOException e)
{
e.printStackTrace ();
}
finally
{
if (out != null)
{
try
{
out.close ();
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
}
//Receive files via socket
public static void receiveFile (final Socket sock, File[] destination)
{
for (int i = 0; i < destination.length; i++)
receiveFile (sock, destination[i]);
}

You need to modify your send/receive protocol to include at least a minimal header before sending the file. Your header should include at least the size of the data to follow, and anything else you might want (such as file name).

I tried with a header like you suggested, but it doesn't work. The receiver still don't know when to stop(so I get EOFException). All the received data get written to the first file.
public static void sendFile (Socket sock, File source)
{
FileInputStream fileIn = null;
try
{
//Read bytes from the source file
fileIn = new FileInputStream(source);
//Write bytes to the receive
//No need to use a buffered class, we make our own buffer.
OutputStream netOut = sock.getOutputStream();
byte[] buffer = new byte[BUFFER_SIZE];
int readBytes = 0;
long fileSize = source.length();
long counter = 0;
//Send the file size
DataOutputStream objOut = new DataOutputStream (netOut);
System.out.println ("Writing: " + source.length ());
objOut.writeLong (fileSize);
objOut.flush ();
while ((counter += readBytes) < fileSize)
{
readBytes = fileIn.read(buffer);
netOut.write(buffer, 0, readBytes);
netOut.flush ();
}
fileIn.close();
}
catch (Exception e)
{
e.printStackTrace ();
}
finally
{
if (fileIn != null)
{
try
{
fileIn.close ();
}
catch (IOException e)
{
e.printStackTrace ();
}
}
}
}
[]
public static void receiveFile (Socket sock, File destination)
{
BufferedOutputStream fileOut = null;
try
{
//Receive data from socket
InputStream netIn = sock.getInputStream();
//Write bytes to a file
fileOut = new BufferedOutputStream (new FileOutputStream (destination));
byte[] buffer = new byte[BUFFER_SIZE];
int readBytes = 0;
long fileSize;
long counter = 0;
//Receive the file size
DataInputStream objIn = new DataInputStream (netIn);
fileSize = objIn.readLong ();
System.out.println ("Receiving: " + fileSize);
while (true)
{
readBytes = netIn.read (buffer);
fileOut.write (buffer, 0, readBytes);
fileOut.flush ();
counter += readBytes;
if (counter > fileSize)
break;
}
}
catch (IOException e)
{
e.printStackTrace ();
}
finally
{
if (fileOut != null)
{
try
{
fileOut.close ();
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
System.out.println ("Ending method");
}