Java:解压缩比压缩慢得多

Question

我有一些压缩文件的代码，通过网络发送它，然后在另一端解压缩它。我仍在测试代码，源和目标是相同的。压缩文件大约需要一分钟。解压缩文件大约需要一个小时。我认为我的代码中一定存在缺陷才能产生如此大的差异。这是解压缩的代码:

public String uncompressLocalZip(String filename,String strUUID,ParentEntry pe,boolean bControlFileProgress) {
        final int BUFFER = 2048;
        BufferedOutputStream out  = null;
        ZipInputStream zis = null;

        try {

            FileInputStream fis = new FileInputStream(Constants.conf.getFileDirectory() + Constants.PATH_SEPARATOR + strUUID + Constants.PATH_SEPARATOR + filename);
            zis = new  ZipInputStream(new BufferedInputStream(fis));
            ZipEntry entry;
            long totallength = 0;
            long size = 0;
            if (pe !=null)
                size = pe.getSize();


            while((entry = zis.getNextEntry()) != null) {
                System.out.println("Extracting: " +entry);
                int count;
                byte data[] = new byte[BUFFER];
                // write the files to the disk

                File fileOutput = new File(Constants.conf.getFileDirectory() + Constants.PATH_SEPARATOR + strUUID + Constants.PATH_SEPARATOR + Constants.conf.getUncompressFolderName() + Constants.PATH_SEPARATOR + entry.getName());
                new File(fileOutput.getParent()).mkdirs();


                BufferedOutputStream fos = new BufferedOutputStream(new FileOutputStream(fileOutput));

                out = new BufferedOutputStream(fos, BUFFER);
                while ((count = zis.read(data, 0, BUFFER)) != -1) {
                       out.write(data, 0, count);
                       totallength += count;

            }
            out.flush();

        }

     }
     catch(Exception e) {
        e.printStackTrace();
        return("FAILED");
     }
     finally {
        try {if ( out!= null) out.close();} catch (IOException ioe) {}
        try {if ( zis!= null) zis.close();} catch (IOException ioe) {}

     }

    return("SUCCESS");      



}

这里是压缩代码:

public void createLocalZip(String filename,ProcessEntry pe) {
    ZipOutputStream out=null;
    try {

        File fileOutput = new File (filename);
        out = new ZipOutputStream(new BufferedOutputStream(new FileOutputStream(fileOutput)));
        long totallength=0;
        long size = pe.getParentEntry().getSize();

        String strStartDirectory;
        if (pe.getParentEntry().isDirectory())
            strStartDirectory=pe.getParentEntry().getUrl();
        else
            strStartDirectory=pe.getParentEntry().getFolder();



        for (int i=0;i<pe.getParentEntry().tableModel3.getRowCount();i++) {
            FileEntry fe = pe.getParentEntry().tableModel3.getFileEntry(i);
            File fileInput = new File (fe.getUrl());
            FileInputStream input = new FileInputStream(fileInput);
            BufferedInputStream in = new BufferedInputStream(input);

            String strRelativeDir = fe.getUrl().substring(strStartDirectory.length()+1,fe.getUrl().length());

            ZipEntry entry = new ZipEntry(strRelativeDir);

            out.putNextEntry(entry);


            byte[] bbuf = new byte[2048];
            int length=0;




             while ((in != null) && ((length = in.read(bbuf)) != -1)) {

                    out.write(bbuf,0,length);
                    totallength += length;
                    pe.setProgress((int) (totallength*100/size));

             }

             in.close();


        }






    }
    catch (Exception e) {
        System.out.println(e.getMessage());
    }
    finally {
        try {if (out!=null) out.close();} catch(IOException ioe){}
    }


}

更新:此特定测试的压缩率约为 90%(1.2GB 降至约 100MB)。所以我想这可能是解压缩与压缩的额外磁盘写入，尽管我预计差异接近 10 倍与 60 倍。

Answer 1

不要用 BufferedOutputStream 双重包装您的 OutputStream(您只需要 1 个 BufferedOutputStream 包装器)，并在完成写入后将其关闭。

此外，ZipEntry 可以是目录，因此请检查并进行相应处理。