解压缩文件非常慢

Question

我编写了一些代码,用于检索zip文件并将其解压缩到directoy中.zip文件包含两个文件夹,根据每个文件所在的文件夹,它将解压缩到该目录的文件夹中.

但是,代码运行时间很长(大约10分钟).虽然,文件夹中每个文件包含近1000个文件,但zip文件的总大小为5000kb.我认为它进展缓慢因为我每次进入循环时都在创建FileOutputStream和InputStream.但是,我需要这样做,因为我不知道文件的输出目录,直到我从zip文件中读取它.(即找出它所在的文件夹)

有什么建议？

/**
 * Retrieves and unzips a file from its URL
 */
public void retrieveFiles(String URL) {

    //Retrieve file from URL
    File zip = new File(getFile(URL));
    zip.mkdirs();

    try {
        //Create .zip file from file directory
        ZipFile zipFile = new ZipFile(zip);
        Enumeration<? extends ZipEntry> enumeration = zipFile.entries();

        //While zip file contains elements, get the next zipped file
        while (enumeration.hasMoreElements()) {
            ZipEntry zipEntry = (ZipEntry) enumeration.nextElement();

            //Ignore folders and other zip files
            if(!zipEntry.isDirectory() && !zipEntry.getName().endsWith(".zip")){

                //Find directory and filename for new unzipped file
                String directory = getURL(zipEntry.getName());
                String fileName = getFileName(zipEntry.getName());
                String fullDirectory = createDirectory(directory, fileName);

                //Unzip file and store in directory
                System.out.println("Unzipping file: " + fileName);
                FileOutputStream fout = new FileOutputStream(fullDirectory);
                InputStream in = zipFile.getInputStream(zipEntry);
                for (int c = in.read(); c != -1; c = in.read()) {
                    fout.write(c);
                }
                zipFile.getInputStream(zipEntry).close();
                in.close();
                fout.close();
            }
        }
        zipFile.close();
        System.out.println("Unzipping complete!");

        zip.delete();

    } catch (IOException e) {
        System.out.println("Unzip failed");
        e.printStackTrace();
    }
}

Answer 1

您正在一次复制一个字节的文件

for (int c = in.read(); c != -1; c = in.read())
    fout.write(c);
}

您可以尝试使用Apaches org.apache.commons.io.IOUtils.copy(),因为这将以块的形式复制并使用NIO和其他改进.你可以在commons-io.jar中找到它