在Java中递归删除目录

在 Java 7+ 中，您可以使用 Files 类。代码很简单：

Path directory = Paths.get("/tmp");
Files.walkFileTree(directory, new SimpleFileVisitor<Path>() {
   @Override
   public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
       Files.delete(file);
       return FileVisitResult.CONTINUE;
   }

   @Override
   public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException {
       Files.delete(dir);
       return FileVisitResult.CONTINUE;
   }
});

---

递归删除所有文件和目录（包括起始目录）的单线解决方案（Java8）：

try (var dirStream = Files.walk(Paths.get("c:/dir_to_delete/"))) {
    dirStream
        .map(Path::toFile)
        .sorted(Comparator.reverseOrder())
        .forEach(File::delete);
}

我们使用比较器来反转顺序，否则 File::delete 将无法删除可能非空的目录。因此，如果您想保留目录并且只删除文件，只需删除 sorted() 中的比较器或完全删除排序并添加文件过滤器：

try (var dirStream = Files.walk(Paths.get("c:/dir_to_delete/"))) {
    dirStream
        .filter(Files::isRegularFile)
        .map(Path::toFile)
        .forEach(File::delete);
}

---

Java 7 添加了对带有符号链接处理的遍历目录的支持：

import java.nio.file.*;

public static void removeRecursive(Path path) throws IOException
{
    Files.walkFileTree(path, new SimpleFileVisitor<Path>()
    {
        @Override
        public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)
                throws IOException
        {
            Files.delete(file);
            return FileVisitResult.CONTINUE;
        }

        @Override
        public FileVisitResult visitFileFailed(Path file, IOException exc) throws IOException
        {
            // try to delete the file anyway, even if its attributes
            // could not be read, since delete-only access is
            // theoretically possible
            Files.delete(file);
            return FileVisitResult.CONTINUE;
        }

        @Override
        public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException
        {
            if (exc == null)
            {
                Files.delete(dir);
                return FileVisitResult.CONTINUE;
            }
            else
            {
                // directory iteration failed; propagate exception
                throw exc;
            }
        }
    });
}

我将其用作特定于平台的方法的后备方法（在此未经测试的代码中）：

public static void removeDirectory(Path directory) throws IOException
{
    // does nothing if non-existent
    if (Files.exists(directory))
    {
        try
        {
            // prefer OS-dependent directory removal tool
            if (SystemUtils.IS_OS_WINDOWS)
                Processes.execute("%ComSpec%", "/C", "RD /S /Q \"" + directory + '"');
            else if (SystemUtils.IS_OS_UNIX)
                Processes.execute("/bin/rm", "-rf", directory.toString());
        }
        catch (ProcessExecutionException | InterruptedException e)
        {
            // fallback to internal implementation on error
        }

        if (Files.exists(directory))
            removeRecursive(directory);
    }
}

（SystemUtils 来自 Apache Commons Lang。进程是私有的，但它的行为应该是显而易见的。）

---

刚刚看到我的解决方案和erickson的差不多，只是封装成静态方法。把它放在某个地方，它比为（如您所见）非常简单的东西安装所有 Apache Commons 轻得多。

public class FileUtils {
    /**
     * By default File#delete fails for non-empty directories, it works like "rm". 
     * We need something a little more brutual - this does the equivalent of "rm -r"
     * @param path Root File Path
     * @return true iff the file and all sub files/directories have been removed
     * @throws FileNotFoundException
     */
    public static boolean deleteRecursive(File path) throws FileNotFoundException{
        if (!path.exists()) throw new FileNotFoundException(path.getAbsolutePath());
        boolean ret = true;
        if (path.isDirectory()){
            for (File f : path.listFiles()){
                ret = ret && deleteRecursive(f);
            }
        }
        return ret && path.delete();
    }
}

---

具有堆栈且没有递归方法的解决方案：

File dir = new File("/path/to/dir");
File[] currList;
Stack<File> stack = new Stack<File>();
stack.push(dir);
while (! stack.isEmpty()) {
    if (stack.lastElement().isDirectory()) {
        currList = stack.lastElement().listFiles();
        if (currList.length > 0) {
            for (File curr: currList) {
                stack.push(curr);
            }
        } else {
            stack.pop().delete();
        }
    } else {
        stack.pop().delete();
    }
}

---

如果您有 Spring，则可以使用 FileSystemUtils.deleteRecursively：

import org.springframework.util.FileSystemUtils;

boolean success = FileSystemUtils.deleteRecursively(new File("directory"));

---

在 Guava 9 之前，Guava 一直支持 Files.deleteRecursively(File)。

从 Guava 10：

已弃用。此方法存在较差的符号链接检测和竞争条件。仅通过使用诸如 rm -rf 或 del /s 之类的操作系统命令才能适当地支持此功能。此方法计划在 Guava 11.0 版中从 Guava 中删除。

因此，Guava 11 中没有这种方法。

---

for(Path p : Files.walk(directoryToDelete).
        sorted((a, b) -> b.compareTo(a)). // reverse; files before dirs
        toArray(Path[]::new))
{
    Files.delete(p);
}

或者，如果您想处理 IOException：

Files.walk(directoryToDelete).
    sorted((a, b) -> b.compareTo(a)). // reverse; files before dirs
    forEach(p -> {
        try { Files.delete(p); }
        catch(IOException e) { /* ... */ }
      });

---

public void deleteRecursive(File path){
    File[] c = path.listFiles();
    System.out.println("Cleaning out folder:" + path.toString());
    for (File file : c){
        if (file.isDirectory()){
            System.out.println("Deleting file:" + file.toString());
            deleteRecursive(file);
            file.delete();
        } else {
            file.delete();
        }
    }
    path.delete();
}

---

public static void deleteDirectory(File path) 
{
    if (path == null)
        return;
    if (path.exists())
    {
        for(File f : path.listFiles())
        {
            if(f.isDirectory()) 
            {
                deleteDirectory(f);
                f.delete();
            }
            else
            {
                f.delete();
            }
        }
        path.delete();
    }
}

---

符号链接和上述代码失败的两种方法......并且不知道解决方案。

方式#1

运行这个来创建一个测试：

echo test > testfile
mkdir dirtodelete
ln -s badlink dirtodelete/badlinktodelete

在这里您可以看到您的测试文件和测试目录：

$ ls testfile dirtodelete
testfile

dirtodelete:
linktodelete

然后运行你的 commons-io deleteDirectory()。它崩溃说找不到文件。不确定其他示例在这里做了什么。 Linux rm 命令会简单地删除链接，并且目录上的 rm -r 也会。

Exception in thread "main" java.io.FileNotFoundException: File does not exist: /tmp/dirtodelete/linktodelete

方式#2

运行这个来创建一个测试：

mkdir testdir
echo test > testdir/testfile
mkdir dirtodelete
ln -s ../testdir dirtodelete/dirlinktodelete

在这里您可以看到您的测试文件和测试目录：

$ ls dirtodelete testdir
dirtodelete:
dirlinktodelete

testdir:
testfile

然后运行您的 commons-io deleteDirectory() 或人们发布的示例代码。它不仅会删除目录，还会删除被删除目录之外的测试文件。 （它隐式地取消引用目录，并删除内容）。 rm -r 只会删除链接。您需要使用类似这样的方法删除取消引用的文件：“find -L ditodelete -type f -exec rm {} \;”。

$ ls dirtodelete testdir
ls: cannot access dirtodelete: No such file or directory
testdir:

---

你可以使用：

org.apache.commons.io.FileUtils.deleteQuietly(destFile);

删除文件，从不抛出异常。如果文件是一个目录，删除它和所有子目录。 File.delete() 和这个方法的区别是： 要删除的目录不一定是空的。无法删除文件或目录时不会引发异常。

---

处理异常的最佳解决方案与从方法引发的异常应始终描述该方法尝试（和失败）执行的方法一致：

private void deleteRecursive(File f) throws Exception {
    try {
        if (f.isDirectory()) {
            for (File c : f.listFiles()) {
                deleteRecursive(c);
            }
        }
        if (!f.delete()) {
            throw new Exception("Delete command returned false for file: " + f);
        }
    } 
    catch (Exception e) {
        throw new Exception("Failed to delete the folder: " + f, e);
    }
}

---

在遗留项目中，我需要创建本机 Java 代码。我创建此代码类似于 Paulitex 代码。看到：

public class FileHelper {

   public static boolean delete(File fileOrFolder) {
      boolean result = true;
      if(fileOrFolder.isDirectory()) {
         for (File file : fileOrFolder.listFiles()) {
            result = result && delete(file);
         }
      }
      result = result && fileOrFolder.delete();
      return result;
   } 
}

和单元测试：

public class FileHelperTest {

    @Before
    public void setup() throws IOException {
       new File("FOLDER_TO_DELETE/SUBFOLDER").mkdirs();
       new File("FOLDER_TO_DELETE/SUBFOLDER_TWO").mkdirs();
       new File("FOLDER_TO_DELETE/SUBFOLDER_TWO/TEST_FILE.txt").createNewFile();
    }

    @Test
    public void deleteFolderWithFiles() {
       File folderToDelete = new File("FOLDER_TO_DELETE");
       Assert.assertTrue(FileHelper.delete(folderToDelete));
       Assert.assertFalse(new File("FOLDER_TO_DELETE").exists());
    }

}

---

下面的代码递归删除给定文件夹中的所有内容。

boolean deleteDirectory(File directoryToBeDeleted) {
    File[] allContents = directoryToBeDeleted.listFiles();
    if (allContents != null) {
        for (File file : allContents) {
            deleteDirectory(file);
        }
    }
    return directoryToBeDeleted.delete();
}

---

这是一个接受命令行参数的简单主要方法，您可能需要附加自己的错误检查或将其塑造成您认为合适的方式。

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;

public class DeleteFiles {

/**
 * @param intitial arguments take in a source to read from and a 
 * destination to read to
 */
    public static void main(String[] args)
                     throws FileNotFoundException,IOException {
        File src = new File(args[0]);
        if (!src.exists() ) {
            System.out.println("FAILURE!");
        }else{
            // Gathers files in directory
            File[] a = src.listFiles();
            for (int i = 0; i < a.length; i++) {
                //Sends files to recursive deletion method
                fileDelete(a[i]);
            }
            // Deletes original source folder
            src.delete();
            System.out.println("Success!");
        }
    }

    /**
     * @param srcFile Source file to examine
     * @throws FileNotFoundException if File not found
     * @throws IOException if File not found
     */
    private static void fileDelete(File srcFile)
                     throws FileNotFoundException, IOException {
        // Checks if file is a directory
        if (srcFile.isDirectory()) {
            //Gathers files in directory
            File[] b = srcFile.listFiles();
            for (int i = 0; i < b.length; i++) {
                //Recursively deletes all files and sub-directories
                fileDelete(b[i]);
            }
            // Deletes original sub-directory file
            srcFile.delete();
        } else {
            srcFile.delete();
        }
    }
}

我希望这会有所帮助！

---

Guava 提供单行：MoreFiles.deleteRecursively()。

与许多共享的示例不同，它考虑了符号链接，并且不会（默认情况下）删除提供的路径之外的文件。

---

也许这个问题的解决方案可能是使用来自 erickson 的答案的代码重新实现 File 类的 delete 方法：

public class MyFile extends File {

  ... <- copy constructor

  public boolean delete() {
    if (f.isDirectory()) {
      for (File c : f.listFiles()) {
        return new MyFile(c).delete();
      }
    } else {
        return f.delete();
    }
  }
}

---

没有 Commons IO 和 < Java SE 7

public static void deleteRecursive(File path){
            path.listFiles(new FileFilter() {
                @Override
                public boolean accept(File pathname) {
                    if (pathname.isDirectory()) {
                        pathname.listFiles(this);
                        pathname.delete();
                    } else {
                        pathname.delete();
                    }
                    return false;
                }
            });
            path.delete();
        }

---

rm -rf 的性能比 FileUtils.deleteDirectory 高得多。

经过广泛的基准测试，我们发现使用 rm -rf 比使用 FileUtils.deleteDirectory 快几倍。

当然，如果您有一个小的或简单的目录，那没关系，但在我们的例子中，我们有多个 GB 和深度嵌套的子目录，使用 FileUtils.deleteDirectory 需要 10 多分钟，而使用 rm -rf 只需 1 分钟。

这是我们的粗略 Java 实现：

// Delete directory given and all subdirectories and files (i.e. recursively).
//
static public boolean deleteDirectory( File file ) throws IOException, InterruptedException {

    if ( file.exists() ) {

        String deleteCommand = "rm -rf " + file.getAbsolutePath();
        Runtime runtime = Runtime.getRuntime();

        Process process = runtime.exec( deleteCommand );
        process.waitFor();

        return true;
    }

    return false;

}

如果您正在处理大型或复杂的目录，则值得尝试。

---

// 带有 lambda 和流的 Java 8，如果参数是目录

static boolean delRecursive(File dir) {
    return Arrays.stream(dir.listFiles()).allMatch((f) -> f.isDirectory() ? delRecursive(f) : f.delete()) && dir.delete();
}

// 如果参数是文件或目录

static boolean delRecursive(File fileOrDir) {
    return fileOrDir.isDirectory() ? Arrays.stream(fileOrDir.listFiles()).allMatch((f) -> delRecursive(f)) && fileOrDir.delete() : fileOrDir.delete();
}

---

Guava 21.0 及更高版本

从 Guava 21.0 开始，MoreFiles 类的 void deleteRecursively(Path path, RecursiveDeleteOption... options) throws IOException 静态方法可用。

请参阅 Javadoc documentation：

public static void deleteRecursively(Path path, RecursiveDeleteOption... options) throws IOException 递归删除给定路径的文件或目录。删除符号链接，而不是它们的目标（受以下警告）。如果尝试读取、打开或删除给定目录下的任何文件时发生 I/O 异常，则此方法会跳过该文件并继续。收集所有此类异常，并在尝试删除所有文件后，抛出一个 IOException，其中包含这些异常作为抑制的异常。

---

虽然可以使用 file.delete() 轻松删除文件，但目录必须为空才能删除。使用递归很容易做到这一点。例如：

public static void clearFolders(String[] args) {
        for(String st : args){
            File folder = new File(st);
            if (folder.isDirectory()) {
                File[] files = folder.listFiles();
                if(files!=null) { 
                    for(File f: files) {
                        if (f.isDirectory()){
                            clearFolders(new String[]{f.getAbsolutePath()});
                            f.delete();
                        } else {
                            f.delete();
                        }
                    }
                }
            }
        }
    }

---

我编写了这个具有 3 个安全标准的例程，以便更安全地使用。

package ch.ethz.idsc.queuey.util;

import java.io.File;
import java.io.IOException;

/** recursive file/directory deletion
 * 
 * safety from erroneous use is enhanced by three criteria
 * 1) checking the depth of the directory tree T to be deleted
 * against a permitted upper bound "max_depth"
 * 2) checking the number of files to be deleted #F
 * against a permitted upper bound "max_count"
 * 3) if deletion of a file or directory fails, the process aborts */
public final class FileDelete {
    /** Example: The command
     * FileDelete.of(new File("/user/name/myapp/recordings/log20171024"), 2, 1000);
     * deletes given directory with sub directories of depth of at most 2,
     * and max number of total files less than 1000. No files are deleted
     * if directory tree exceeds 2, or total of files exceed 1000.
     * 
     * abort criteria are described at top of class
     * 
     * @param file
     * @param max_depth
     * @param max_count
     * @return
     * @throws Exception if criteria are not met */
    public static FileDelete of(File file, int max_depth, int max_count) throws IOException {
        return new FileDelete(file, max_depth, max_count);
    }

    // ---
    private final File root;
    private final int max_depth;
    private int removed = 0;

    /** @param root file or a directory. If root is a file, the file will be deleted.
     *            If root is a directory, the directory tree will be deleted.
     * @param max_depth of directory visitor
     * @param max_count of files to delete
     * @throws IOException */
    private FileDelete(final File root, final int max_depth, final int max_count) throws IOException {
        this.root = root;
        this.max_depth = max_depth;
        // ---
        final int count = visitRecursively(root, 0, false);
        if (count <= max_count) // abort criteria 2)
            visitRecursively(root, 0, true);
        else
            throw new IOException("more files to be deleted than allowed (" + max_count + "<=" + count + ") in " + root);
    }

    private int visitRecursively(final File file, final int depth, final boolean delete) throws IOException {
        if (max_depth < depth) // enforce depth limit, abort criteria 1)
            throw new IOException("directory tree exceeds permitted depth");
        // ---
        int count = 0;
        if (file.isDirectory()) // if file is a directory, recur
            for (File entry : file.listFiles())
                count += visitRecursively(entry, depth + 1, delete);
        ++count; // count file as visited
        if (delete) {
            final boolean deleted = file.delete();
            if (!deleted) // abort criteria 3)
                throw new IOException("cannot delete " + file.getAbsolutePath());
            ++removed;
        }
        return count;
    }

    public int deletedCount() {
        return removed;
    }

    public void printNotification() {
        int count = deletedCount();
        if (0 < count)
            System.out.println("deleted " + count + " file(s) in " + root);
    }
}

---