压缩压缩

Question

我试图使用java将目录内容压缩到zip归档中。一切都很好，但我只想澄清一些事实。下面是我用来压缩文件的代码：

public void pack(@Nonnull String archiveName, @Nonnull File outputDir, @Nonnull File targetDir) {
  File zipFile = new File(outputDir, "out.zip");

  ZipOutputStream zipOutputStream = null;
  OutputStream outputStream;
  try {
    // create stream for writing zip archive
    outputStream = new FileOutputStream(zipFile);
    zipOutputStream = new ZipOutputStream(outputStream);
    // write files recursively
    writeFiles(zipOutputStream, targetDir.listFiles(), "");
  } catch (IOException e) {
    LOGGER.error("IO exception while packing files to archive", e);
  } finally {
    // close output streams
    if (zipOutputStream != null) {
      try {
        zipOutputStream.close();
      } catch (IOException e) {
        LOGGER.error("Unable to close zip output stream", e);
      }
    }
  }
}

/**
 * Writes specified files and their children (in case of directories) to archive
 *
 * @param zipOutputStream archive output stream
 * @param files           which should be added to archive
 * @param path            path relative of root of archive where files should be placed
 */
private void writeFiles(@Nonnull ZipOutputStream zipOutputStream, @Nullable File[] files, @Nonnull String path) throws IOException {
  if (files == null || files.length == 0) {
    return;
  }

  for (File file : files) {
    if (file.isDirectory()) {
      // recursively add files in this directory
      String fullDirectoryName = path + file.getName() + "/";
      File[] childFiles = file.listFiles();
      if (childFiles != null && childFiles.length > 0) {
        // write child files to archive. current directory will be created automatically
        writeFiles(zipOutputStream, childFiles, fullDirectoryName);
      } else {
        // empty directory. write directory itself to archive
        ZipEntry entry = new ZipEntry(fullDirectoryName);
        zipOutputStream.putNextEntry(entry);
        zipOutputStream.closeEntry();
      }
    } else {
      // put file in archive
      BufferedInputStream bufferedInputStream = new BufferedInputStream(new FileInputStream(file));
      zipOutputStream.putNextEntry(new ZipEntry(path + file.getName()));
      ByteStreams.copy(bufferedInputStream, zipOutputStream);
      zipOutputStream.closeEntry();
      bufferedInputStream.close();
    }
  }
}

现在有一些问题：

1. 在默认情况下(在我的情况下也是如此)，我将获得已经压缩的存档(使用Deflate方法)，这是否正确？
2. 如何获得未压缩的存档：

- If I set method `zipOutputStream.setMethod(ZipOutputStream.STORED)` I have to provide size, compressed size (is it will be equal to size?) and crc, otherwise I will get exceptions
- If I don't want to calculate size and crc by myself I can use `DEFLATE` method with zero level: zipOutputStream.setMethod(ZipOutputStream.DEFLATED); zipOutputStream.setLevel(ZipOutputStream.STORED);

，那么，在这种情况下，我完全没有压缩存档，这是正确的吗？

-是否有更方便-明显的方法来创建非压缩档案？

​

Answer 1

与其重新发明轮子，我会认真考虑使用一个现有的库来实现这一点，比如Apache。创建zip文件的基本习语是：

Project p = new Project();
p.init();
Zip zip = new Zip();
zip.setProject(p);
zip.setDestFile(new File(outputDir, "out.zip"));
FileSet fs = new FileSet();
fs.setProject(p);
fs.setDirectory(targetDir);
zip.addFileset(fs);
zip.perform();

默认情况下，您将得到一个压缩的存档。对于未压缩的压缩压缩，只需添加以下内容

zip.setCompress(false);

在setDestFile之后(实际上在perform之前的任何地方)。