java.lang.UnsupportedOperationException : 'posix:permissions' not supported as initial attribute on Windows

Question

我正在使用 Java 7 文件 API。我编写了一个类，该类在 Ubuntu 上完美地创建目录，但当我在 Windows 上运行相同的代码时，它会抛出错误:

Exception in thread "main" java.lang.UnsupportedOperationException: 'posix:permissions' not supported as initial attribute
    at sun.nio.fs.WindowsSecurityDescriptor.fromAttribute(Unknown Source)
    at sun.nio.fs.WindowsFileSystemProvider.createDirectory(Unknown Source)
    at java.nio.file.Files.createDirectory(Unknown Source)
    at java.nio.file.Files.createAndCheckIsDirectory(Unknown Source)
    at java.nio.file.Files.createDirectories(Unknown Source)
    at com.cloudspoke.folder_permission.Folder.createFolder(Folder.java:27)
    at com.cloudspoke.folder_permission.Main.main(Main.java:139)

我的文件夹类代码是

package com.cloudspoke.folder_permission;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.attribute.FileAttribute;
import java.nio.file.attribute.PosixFilePermission;
import java.nio.file.attribute.UserPrincipal;
import java.util.Set;

public class Folder{
    // attributes required for creating a Folder
    private UserPrincipal owner;
    private Path folder_name;
    private FileAttribute<Set<PosixFilePermission>> attr;


    public Folder(UserPrincipal owner,Path folder_name,FileAttribute<Set<PosixFilePermission>> attr){
        this.owner=owner;
        this.folder_name=folder_name;
        this.attr=attr;
    }
    //invoking this method will create folders
    public  void createFolder(){
        try {
            //createDirectories function is used for overwriting existing folder instead of createDirectory() method
            Files.createDirectories(folder_name, attr);
            Files.setOwner(folder_name, owner);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        System.out.println("created Folder "+this.folder_name);

    }
}

错误来自于Folder的createFolder方法。

如何解决此错误？

Answer 1

您使用的 PosixFilePermission 只能用于与 POSIX 兼容的操作系统:

A file attribute view that provides a view of the file attributes commonly associated with files on file systems used by operating systems that implement the Portable Operating System Interface (POSIX) family of standards.

Operating systems that implement the POSIX family of standards commonly use file systems that have a file owner, group-owner, and related access permissions. This file attribute view provides read and write access to these attributes`

不幸的是，Windows 不支持 POSIX 文件系统，因此这就是您的代码无法工作的原因。为了在 Windows 中创建目录，您应该使用:

new File("/path/to/folder").mkdir();

在 Windows 中，/ 将自动更改为 \。如果您想立即创建整个路径，则必须使用 mkdirs() 方法。更多信息:http://docs.oracle.com/javase/6/docs/api/java/io/File.html

为了在 Windows 中设置文件权限，您必须使用 setReadable()、setWritable() 和 setExecutable()。这是 File 类方法，仅设置文件所有者的权限。请注意，上述方法是在 Java 1.6 中添加的。在旧版本中，您必须使用(Windows 版本):

Runtime.getRuntime().exec("attrib -r myFile");