ZipOutputStream appends characters to beginning of zipped file?

Question

Hi and thanks in advance for any help!
I am trying to zip Excel files using ZipOutputStream class. I can open the Excel files fine before I zip. Then I run my program to zip. It seems to work. I use WinZip to unzip and when I try and open unzipped file in Excel, Excel says it does not recognize format. Looking at unzipped file in text editor, about 15 wierd characters and nulls are now appended to the beginning of my Excel file that are not in the original. If I delete them in the text editor, Excel can open.
Here is my zip code:
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ZipOutputStream zos = new ZipOutputStream(baos);
ArrayList fileNames = new ArrayList();
fileNames.add ("91PSAG0Jak.csv");
fileNames.add ("91I9F60K62.csv");
// Compress the files
for (int i=0; i<2; i++) {
String filename = String.valueOf(fileNames.get(i));
byte[] file = DatabaseUtilities.downloadFile("pdfstoragedir", filename);
// Add ZIP entry to output stream.
zos.putNextEntry(new ZipEntry(filename));
ObjectOutputStream oos = new ObjectOutputStream (zos);
oos.writeObject(file);
oos.flush();
// Complete the entry
zos.closeEntry();
//Complete the ZIP file
zos.close();
byte[] zipFile = baos.toByteArray();
DatabaseUtilities.uploadFile("pdfstoragedir", "zipOutput.zip", zipFile);
FileOutputStream fos = new FileOutputStream("C:\\zipOutput.zip");
BufferedOutputStream bos = new BufferedOutputStream(fos);
bos.write(zipFile, 0, zipFile.length);

Answer 1

Thanks, I got it I think, I can write my byte[] directly to the zipOutputStream:
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ZipOutputStream zos = new ZipOutputStream(baos);
ArrayList fileNames = new ArrayList();
fileNames.add ("8aCeOH0Fba.zip");
fileNames.add ("8da6S40H4e.zip");
// Compress the files
for (int i=0; i<2; i++) {
String filename = String.valueOf(fileNames.get(i));
byte[] file = DatabaseUtilities.downloadFile("pdfstoragedir", filename);
// Add ZIP entry to output stream.
zos.putNextEntry(new ZipEntry(filename));
zos.write(file);
// Complete the entry
zos.closeEntry();
//Complete the ZIP file
zos.close();
byte[] zipFile = baos.toByteArray();
DatabaseUtilities.uploadFile("pdfstoragedir", "zipOutput.zip", zipFile);
FileOutputStream fos = new FileOutputStream("C:\\zipOutput.zip");
BufferedOutputStream bos = new BufferedOutputStream(fos);
bos.write(zipFile, 0, zipFile.length);