使用 java.util.zip.ZipOutputStream 时 zip 文件中的目录

directories in a zip file when using java.util.zip.ZipOutputStream

提问by Bala

Lets say I have a file t.txt, a directory t and another file t/t2.txt. If I use the linux zip utility "zip -r t.zip t.txt t", I get a zip file with the following entries in them (unzip -l t.zip):

假设我有一个文件 t.txt、一个目录 t 和另一个文件 t/t2.txt。如果我使用 linux zip 实用程序“zip -r t.zip t.txt t”，我会得到一个包含以下条目的 zip 文件（unzip -l t.zip）：

Archive:  t.zip
  Length     Date   Time    Name
 --------        ----      ----      ----
        9  04-11-09 09:11   t.txt
        0  04-11-09 09:12   t/
      15  04-11-09 09:12   t/t2.txt
 --------                           -------
       24                          3 files

If I try to replicate that behavior with java.util.zip.ZipOutputStream and create a zip entry for the directory, java throws an exception. It can handle only files. I can create a t/t2.txt entry in the zip file and add use the t2.txt file contents to it but I can't create the directory. Why is that?

如果我尝试使用 java.util.zip.ZipOutputStream 复制该行为并为该目录创建一个 zip 条目，java 将引发异常。它只能处理文件。我可以在 zip 文件中创建 at/t2.txt 条目并将使用 t2.txt 文件内容添加到其中，但我无法创建目录。这是为什么？

回答by John Ellinwood

ZipOutputStreamcanhandle empty directories by adding a forward-slash /after the folder name. Try (from)

ZipOutputStream可以通过/在文件夹名称后添加正斜杠来处理空目录。尝试（来自）

public class Test {
    public static void main(String[] args) {
        try {
            FileOutputStream f = new FileOutputStream("test.zip");
            ZipOutputStream zip = new ZipOutputStream(new BufferedOutputStream(f));
            zip.putNextEntry(new ZipEntry("xml/"));
            zip.putNextEntry(new ZipEntry("xml/xml"));
            zip.close();
        } catch(Exception e) {
            System.out.println(e.getMessage());
        }
    }
}

回答by John Ellinwood

You can add "/" at the end of folder name. Just use the following command:

您可以在文件夹名称的末尾添加“/”。只需使用以下命令：

zip.putNextEntry(new ZipEntry("xml/"));

回答by user769087

Just go through the source of java.util.zip.ZipEntry. It treats a ZipEntry as directory if its name ends with "/" characters. Just suffix the directory name with "/".

只需查看 java.util.zip.ZipEntry 的源代码。如果名称以“/”字符结尾，则将 ZipEntry 视为目录。只需在目录名后缀“/”。

Check this example for zipping just the empty directories, http://bethecoder.com/applications/tutorials/showTutorials.action?tutorialId=Java_ZipUtilities_ZipEmptyDirectory

检查此示例以仅压缩空目录，http://bethecoder.com/applications/tutorials/showTutorials.action?tutorialId=Java_ZipUtilities_ZipEmptyDirectory

Good luck.

祝你好运。

回答by programmmer

Java Program to Zip(folders contains either empty or full ones)

Java Program to Zip（文件夹包含空的或完整的）

public class ZipUsingJavaUtil {
    /*
     * Zip function zip all files and folders
     */
    @Override
    @SuppressWarnings("finally")
    public boolean zipFiles(String srcFolder, String destZipFile) {
        boolean result = false;
        try {
            System.out.println("Program Start zipping the given files");
            /*
             * send to the zip procedure
             */
            zipFolder(srcFolder, destZipFile);
            result = true;
            System.out.println("Given files are successfully zipped");
        } catch (Exception e) {
            System.out.println("Some Errors happned during the zip process");
        } finally {
            return result;
        }
    }

    /*
     * zip the folders
     */
    private void zipFolder(String srcFolder, String destZipFile) throws Exception {
        ZipOutputStream zip = null;
        FileOutputStream fileWriter = null;
        /*
         * create the output stream to zip file result
         */
        fileWriter = new FileOutputStream(destZipFile);
        zip = new ZipOutputStream(fileWriter);
        /*
         * add the folder to the zip
         */
        addFolderToZip("", srcFolder, zip);
        /*
         * close the zip objects
         */
        zip.flush();
        zip.close();
    }

    /*
     * recursively add files to the zip files
     */
    private void addFileToZip(String path, String srcFile, ZipOutputStream zip, boolean flag) throws Exception {
        /*
         * create the file object for inputs
         */
        File folder = new File(srcFile);

        /*
         * if the folder is empty add empty folder to the Zip file
         */
        if (flag == true) {
            zip.putNextEntry(new ZipEntry(path + "/" + folder.getName() + "/"));
        } else { /*
                 * if the current name is directory, recursively traverse it
                 * to get the files
                 */
            if (folder.isDirectory()) {
                /*
                 * if folder is not empty
                 */
                addFolderToZip(path, srcFile, zip);
            } else {
                /*
                 * write the file to the output
                 */
                byte[] buf = new byte[1024];
                int len;
                FileInputStream in = new FileInputStream(srcFile);
                zip.putNextEntry(new ZipEntry(path + "/" + folder.getName()));
                while ((len = in.read(buf)) > 0) {
                    /*
                     * Write the Result
                     */
                    zip.write(buf, 0, len);
                }
            }
        }
    }

    /*
     * add folder to the zip file
     */
    private void addFolderToZip(String path, String srcFolder, ZipOutputStream zip) throws Exception {
        File folder = new File(srcFolder);

        /*
         * check the empty folder
         */
        if (folder.list().length == 0) {
            System.out.println(folder.getName());
            addFileToZip(path, srcFolder, zip, true);
        } else {
            /*
             * list the files in the folder
             */
            for (String fileName : folder.list()) {
                if (path.equals("")) {
                    addFileToZip(folder.getName(), srcFolder + "/" + fileName, zip, false);
                } else {
                    addFileToZip(path + "/" + folder.getName(), srcFolder + "/" + fileName, zip, false);
                }
            }
        }
    }
}

回答by chenop

Like others said here to add empty directory add "/" to the directory name. Pay attention NOT to add File.separator (equals to "\") which actually add an empty file to the zip.

像其他人说的在这里添加空目录在目录名称中添加“/”。注意不要添加 File.separator（等于“\”），它实际上将一个空文件添加到 zip 中。

It took me a while to understand what was my mistake - hope I save other some time...

我花了一段时间才明白我的错误是什么 - 希望我能节省一些时间......

回答by Joy Joseph

String dir = "E:\Infor\Marketing\JobLog\Cloud_MomBuild_NoMirror";

String dir = "E:\Infor\Marketing\JobLog\Cloud_MomBuild_NoMirror";

public void downloadAsZip() throws IOException {
    ByteArrayOutputStream byteOutputStream = new ByteArrayOutputStream();
    ZipOutputStream zipOutputStream = new ZipOutputStream(byteOutputStream);
    Path folderPath = Paths.get(dir);
    String folderName = "Output";
    for (File file : folderPath.toFile().listFiles()) {
        String path = folderName + "/" + file.getName();
        if (file.isDirectory()) {
            writeFolderToZip(zipOutputStream, file, path);
        } else {
            writeFileToZip(zipOutputStream, file, path);
        }
    }
}

public void writeFileToZip(ZipOutputStream zipOutputStream, File file, String path) throws IOException {
    zipOutputStream.putNextEntry(new ZipEntry(path));
    FileInputStream fileInputStream = new FileInputStream(file);
    IOUtils.copy(fileInputStream, zipOutputStream);
    fileInputStream.close();
    zipOutputStream.closeEntry();
}

public void writeFolderToZip(ZipOutputStream zipOutputStream, File dir, String path) throws IOException {
    for (File file : dir.listFiles()) {
        String dirPath = path + "/" + file.getName();
        if (file.isDirectory()) {
            writeFolderToZip(zipOutputStream, file, dirPath);
        } else {
            writeFileToZip(zipOutputStream, file, dirPath);
        }
    }
}