Zipping & Unzipping

Zip files with a ZipOutputStream.

For each file:

create a ZipEntry
put the entry in the output stream
copy the file to the output stream
close the entry

ZipOutputStream

+ ZipOutputStream(OutputStream)
+ putNextEntry(ZipEntry)
+ write(int)
+ closeEntry()
+ close()

Unzip files with a ZipFile.
For each ZipEntry:

get an input stream for the entry
open an output stream for the file
copy the file to the output stream
close the streams

ZipFile

+ ZipFile(File)
+ ZipFile(String)
+ entries() : Enumeration
+ getInputStream(ZipEntry) : InputStream
+ close()

void zipFiles(File[] files, File zipFile) throws IOException {
    ZipOutputStream zip = new ZipOutputStream(
                          new BufferedOutputStream(
                          new FileOutputStream(zipFile)));

    for (int i = 0; i < files.length; i++) {
        InputStream in = new BufferedInputStream(
                         new FileInputStream(files[i]));
        ZipEntry entry = new ZipEntry(files[i].getName());

        zip.putNextEntry(entry);
        int b;
        while ((b = in.read()) != -1) {
            zip.write(b);
        }
        zip.closeEntry();
        in.close();
    }
    zip.close();
}

void unzipFiles(File file) throws IOException {
    ZipFile zipFile = new ZipFile(file);

    Enumeration entries = zipFile.entries();
    while (entries.hasMoreElements()) {
        ZipEntry entry = (ZipEntry) entries.nextElement();

        InputStream  in  = new BufferedInputStream(
                           zipFile.getInputStream(entry));
        OutputStream out = new BufferedOutputStream(
                           new FileOutputStream(entry.getName()));
        int b;
        while ((b = in.read()) != -1) {
            out.write(b);
        }
        in.close();
        out.close();
    }
}