zip helpers

ZipHelpers.java

package my.big.fucking.package;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

public class ZipHelpers {

    /**
     * Create a byte array of a single zipped "file".
     * For multiple files @see zipBytes(String[] filenames, String[] contents)
     *
     * To ensure Spring sends an actual zipfile, use
     * <code>@RequestMapping(...blah, produces = "application/zip")</code>
     * add an attachment header:
     * <code>response.addHeader("Content-Disposition", "attachment; filename=example.zip");</code>
     * and return the results of zipBytes
     *
     * @param filename the name for compressed @param bytes
     * @param bytes the contents of "file" @param filename
     * @return a byte array suitable to be returned from Spring Controller
     * @throws IOException
     */
    public static byte[] zipBytes(String filename, byte[] bytes) throws IOException {

        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        ZipOutputStream zipOutputStream = new ZipOutputStream(byteArrayOutputStream);

        ZipEntry entry = new ZipEntry(filename);
        entry.setSize(bytes.length);
        zipOutputStream.putNextEntry(entry);
        zipOutputStream.write(bytes, 0, bytes.length);
        zipOutputStream.closeEntry();
        zipOutputStream.close();

        return byteArrayOutputStream.toByteArray();
    }


    /**
     * Create a byte array of multiple zipped "files". @see #zipBytes(String filename, byte[] bytes)
     * for instructions on how to make this work with Spring.
     *
     * @param filenames list of filenames, one for each index of @param contents
     * @param contents list of file contents, one index for each filename in @param filenames
     * @return a byte array suitable to be returned from Spring Controller
     * @throws IOException
     */
    public static byte[] zipBytes(String[] filenames, String[] contents) throws IOException {
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        ZipOutputStream zipOutputStream = new ZipOutputStream(byteArrayOutputStream);

        for (int i = 0; i < filenames.length; i++) {
            byte[] content = contents[i].getBytes();
            int contentLength = content.length;

            ZipEntry entry = new ZipEntry(filenames[i]);
            entry.setSize(contentLength);
            zipOutputStream.putNextEntry(entry);
            zipOutputStream.write(content, 0, contentLength);
            zipOutputStream.closeEntry();
        }

        zipOutputStream.close();

        return byteArrayOutputStream.toByteArray();
    }

}