Question

I have a method to zip files in Java:

public void compress(File[] inputFiles, OutputStream outputStream) {

    Validate.notNull(inputFiles, "Input files are required");
    Validate.notNull(outputStream, "Output stream is required");

    int BUFFER = 2048;

    BufferedInputStream origin = null;

    ZipOutputStream out = new ZipOutputStream(new BufferedOutputStream(outputStream));
    byte data[] = new byte[BUFFER];

    for (File f : inputFiles) {
        FileInputStream fi;
        try {
            fi = new FileInputStream(f);
        } catch (FileNotFoundException e) {
            throw new RuntimeException("Input file not found", e);
        }
        origin = new BufferedInputStream(fi, BUFFER);
        ZipEntry entry = new ZipEntry(f.getName());
        try {
            out.putNextEntry(entry);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        int count;
        try {
            while ((count = origin.read(data, 0, BUFFER)) != -1) {
                out.write(data, 0, count);
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        try {
            origin.close();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    try {
        out.close();
    } catch (IOException e) {
        throw new RuntimeException(e);
    }
}

As you can see parameter inputFiles is an Array of File objects. This all works, but I’d like to have instead a collection of InputStream objects as parameter to make it more flexible.

But then I have the problem that when making a new ZipEntry (as in code above)

ZipEntry entry = new ZipEntry(f.getName());

I don’t have a filename to give as parameter.

How should i solve this? Maybe a Map with (fileName,inputStream) pairs?

Any thoughts on this are appreciated!

Thanks,
Nathan

Answer 1

I think your suggestion Map<String, InputStream> is a good solution.

Just a side note: Remember to close the inputstreams after you are done

---

If you want to make it more “fancy” you can always use create an interface:

interface ZipOuputInterface {
    String getName();
    InputStream getInputStream();
}

And have it implemented differently in your different cases for instance File:

class FileZipOutputInterface implements ZipOutputInterface {

    File file;

    public FileZipOutputInterface(File file) {
        this.file = file;
    }

    public String getName() {
        return file.getAbstractName();
    }
    public InputStream getInputStream() {
        return new FileInputStream(file);
    }
}