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Java.util.zip.ZipException: invalid entry size (expected 18401 but got 0 bytes) when using putNextEntry() in ZipOutputStream?

I converted a zip file of 5 files into a byte array. I want to output a zip file on my disk from that bytearray. My process was first reading the byte[] into a ByteArrayInputStream then into a ZipInputStream.
InputStream plainTextStream = new ByteArrayInputStream(plainText);
ZipInputStream zipInStream = new ZipInputStream(plainTextStream);
I want this to be outputted into a zip file on my disk so here I thought I will need a file and a ZipOutPutStream passing that zip file.
ZipOutputStream zipOutStream = new ZipOutputStream(new FileOutputStream(file));
With a zip entry I traversed the ZipInPutStream writing to a FileOutputStream each entry, using a buffer. At the end of each main loop I put an entry into the ZipOutPutStream.
ZipEntry entry = null;
while((entry = zipInStream.getNextEntry()) != null){
FileOutputStream fileOutStream = new FileOutputStream(entry.getName());
byte[] byteBuff = new byte[1024];
int bytesRead = 0;
while ((bytesRead = zipInStream.read(byteBuff)) != -1)
{
fileOutStream.write(byteBuff, 0, bytesRead);
}
fileOutStream.close();
zipOutStream.putNextEntry(entry);
zipInStream.closeEntry();
}
I add the first file from the zip (there are 5 files), but when trying to add the 2nd file, I get an error on
zipOutStream.putNextEntry(entry)
java.util.zip.ZipException: invalid entry size (expected 18401 but got 0 bytes)
Through debugging I can't figure out where it goes wrong. I assume it may have something to do with the buffer when putting in the first outputstream(entry.getName())? The bytesRead while loop could be an issue.
This is all assuming the logic makes sense. I hope I can approach a solution to this error.

You never write the content of the zipped files to the zip output stream.
You don't need to write the output to a file stream, just write it directly to the zip output stream.
You should be using try-with-resources.
try (ZipInputStream zipInStream = new ZipInputStream(new ByteArrayInputStream(plainText));
ZipOutputStream zipOutStream = new ZipOutputStream(new FileOutputStream(file));
) {
byte[] byteBuff = new byte[1024];
for (ZipEntry entry; (entry = zipInStream.getNextEntry()) != null; ) {
zipOutStream.putNextEntry(entry);
for (int bytesRead; (bytesRead = zipInStream.read(byteBuff)) != -1; ) {
zipOutStream.write(byteBuff, 0, bytesRead);
}
}
}
There is no need to call closeEntry().

To resolve (expected 18401 but got 0 bytes)
Create a new blank excel file.
Copy data from the file you copied from zip to the new created file in step 1.
Use the new file, it should work as its worked for me.
Thanks.

zipping files in java memory produces a zip file but the files inside are empty

I am trying to zip multiple files in Java to be used in my jar. 2 files are images and 1 is an HTML temp file. Upon zipping these files, when I try to see the contents of the zip file, all 3 files have become empty. There is no error being thrown as the files are in the zip but they are empty for some reason. I need to save my zip file in memory.
Here is my zip code.
public static File zipPdf(File data, File cover) throws IOException {
ArrayList<ByteArrayOutputStream> zips = new ArrayList<>();
ClassLoader loader = RunningPDF.class.getClassLoader();
File image = new File(Objects.requireNonNull(loader.getResource("chekklogo.png")).getFile());
File man = new File(Objects.requireNonNull(loader.getResource("manlogo.jpg")).getFile());
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try(ZipOutputStream zos = new ZipOutputStream(baos)) {
ZipEntry entry = new ZipEntry(data.getName());
zos.putNextEntry(entry);
ZipEntry entry2 = new ZipEntry(image.getName());
zos.putNextEntry(entry2);
ZipEntry entry3 = new ZipEntry(man.getName());
zos.putNextEntry(entry3);
} catch(IOException ioe) {
ioe.printStackTrace();
}

You forget to write the bytes. The putNextEntry just adds an entry. You need to explicitly write the bytes. Go with the following
File file = new File(filePath);
String zipFileName = file.getName().concat(".zip");
FileOutputStream fos = new FileOutputStream(zipFileName);
ZipOutputStream zos = new ZipOutputStream(fos);
zos.putNextEntry(new ZipEntry(file.getName()));
byte[] bytes = Files.readAllBytes(Paths.get(filePath));
zos.write(bytes, 0, bytes.length);
zos.closeEntry();
zos.close();

Corrupted zip file using ZipOutputStream

I'm trying to create a zip file to be able to send multiple files over http.
My issue is that the Zip file that is generated is "corrupted" before and after the file has been send. The issue is i'm not able to find what i did wrong as i'm getting no errors inside the console.
So does someone has an idea file my generated zip file is corrupted ?
This is my code :
OutputStream responseBody = t.getResponseBody();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ZipOutputStream zos = new ZipOutputStream(baos);
int counter = 1;
for (PDDocument doc : documents)
{
ZipEntry zipEntry = new ZipEntry("document" + counter);
zos.putNextEntry(zipEntry);
ByteArrayOutputStream docOs = new ByteArrayOutputStream();
doc.save(docOs);
docOs.close();
zos.write(docOs.toByteArray());
zos.closeEntry();
zos.finish();
zos.flush();
counter++;
}
zos.close();
baos.close();
responseBody.write(baos.toByteArray());
responseBody.flush();
Thank you for your help !

You need to remove zos.finish() from inside the loop as it terminates the ZIP entries, as it is handled by zos.close() at end of the stream.
With very large streams you will be better off sending ZIP directly to responseBody bypassing ByteArrayOutputStream memory buffer.
If you are still having problems check the content type of the output is set. It might be easier to debug by temporarily writing the byte[] to file to check the ZIP format you are sending with:
Files.write(Path.of("temp.zip"), baos.toByteArray());
This outline below shows sending a simple ZIP over http (from a servlet, adjust the first 2 lines to appropriate calls for "t"). This may help you check which step of your code causes the corruption if you work back to adding your own document objects inside the loop:
// MUST set response content type:
// resp.setContentType("application/zip");
OutputStream out = resp.getOutputStream(); // or t.getResponseBody();
try(ZipOutputStream zos = new ZipOutputStream(out))
{
while (counter-- > 0)
{
ZipEntry zipEntry = new ZipEntry("document" + counter+".txt");
zos.putNextEntry(zipEntry);
zos.write(("This is ZipEntry: "+zipEntry.getName()+"\r\n").getBytes());
}
}

JAVA char[] to Zip to File

I have a chararray which holds coordinates in every index. I want to compress the array with zip algorithm and write the zipped version of the array to a file. My idea was that i run the chararray through a zip stream and write it afterwards directly to a file like test.txt. The problem is, that nothing is written to the file after the execution of the code. Can somebody please help me solve that problem?
Kind regards Lorenzo
Here my current code:
byte[] bytes = Charset.forName("UTF-8").encode(CharBuffer.wrap(sample)).array();
FileOutputStream out = new FileOutputStream(cscFile, true);
byte[] compressed = new byte[bytes.length];
ByteArrayInputStream bi = new ByteArrayInputStream(bytes);
ZipInputStream zi = new ZipInputStream(bi);
ZipEntry entry = null;
while ((entry = zi.getNextEntry()) != null) {
zi.read(compressed);
for(int i = 0; i<bytes.length;i++){
out.write(compressed[i]);
}
out.flush();
out.close();
zi.closeEntry();
}
zi.close();

You will probably have to slightly modify your code with something like this:
ZipOutputStream zos = new ZipOutputStream(new FileOutputStream(new File("your zip file name")));
ZipEntry entry = new ZipEntry("zipped file name");
entry.setSize(bytes.length);
zos.putNextEntry(entry);
zos.write(bytes);
zos.closeEntry();
zos.close();
Explanation:
To compress writen data, use ZipOutputStream and give created FileOutputStream as constructor argument. After that, create ZipEntry, which represents file inside your zip file and write contents of byte array into it.
Hope it helps.
See similar question here: https://stackoverflow.com/a/357892/3115098

in memory file zip in java

I am trying to read multiple files (can be of any format i.e. pdf, txt, tiff etc) from URLs and zipping them using ZipOutputStream. My code looks like this:
// using in-memory file read
// then zipping all these files in-memory
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ZipOutputStream zos = new ZipOutputStream(baos);
.....
URL url = new URL(downloadUrl); // can be multiple URLs
ByteArrayOutputStream bais = new ByteArrayOutputStream();
InputStream is = url.openStream();
byte[] byteChunk = new byte[4096];
int n;
while ( (n = is.read(byteChunk)) > 0 )
{
bais.write(byteChunk, 0, n);
}
byte[] fileBytes = bais.toByteArray();
ZipEntry entry = new ZipEntry(fileName);
entry.setSize(fileBytes.length);
zos.putNextEntry(entry);
zos.write(fileBytes);
zos.closeEntry();
// close the url input stream
is.close();
// close the zip output stream
zos.close();
// read the byte array from ByteArrayOutputStream
byte[] zipFileBytes = baos.toByteArray();
String fileContent = new String(zipFileBytes);
I am then passing this content "fileContent" to my perl frontend application.
And I m using perl code to download this zipped file:
WPHTTPResponse::setHeader( 'Content-disposition', 'attachment; filename="test.zip"' );
WPHTTPResponse::setHeader( 'Content-type', 'application/zip');
print $result; // string coming from java application
But the zip file it is giving is corrupted. I think something in going wrong with the data translation.
I'd appreciate any help.

Your problem is thinking that you can output your zip bytes into a string. This string can not be used to reproduce the zip content again. You need to either use the raw bytes or encode the bytes into something that can be represented as a string, such as base64 encoding.