如何使用java修改文件所有者及其权限

这篇文章主要介绍了如何使用java修改文件所有者及其权限,文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下

1.设置所有者

管理文件所有者

Files.getOwner()和Files.setOwner()方法

要使用UserPrincipal来管理文件的所有者

（1）更改文件的所有者

import java.io.IOException;
import java.nio.file.*;
import java.nio.file.attribute.FileOwnerAttributeView;
import java.nio.file.attribute.UserPrincipal;
import java.nio.file.attribute.UserPrincipalLookupService;

public class Main {
  public static void main(String[] args) {

    Path path = Paths.get("/www/test1.txt");

    FileOwnerAttributeView foav = Files.getFileAttributeView(path,
        FileOwnerAttributeView.class);
    try {
      UserPrincipal owner = foav.getOwner();
      System.out.format("Original owner of %s is %s%n", path,
          owner.getName());

      FileSystem fs = FileSystems.getDefault();
      UserPrincipalLookupService upls = fs.getUserPrincipalLookupService();

      UserPrincipal newOwner = upls.lookupPrincipalByName("abc");
      foav.setOwner(newOwner);

      UserPrincipal changedOwner = foav.getOwner();
      System.out.format("New owner of %s is %s%n", path,
          changedOwner.getName());

    }catch (IOException e){
      e.printStackTrace();
    }

  }
}

输出

查看文件详细信息

2.ACL文件权限

Windows上支持ACL类型文件属性

使用AclFileAttributeView的

　　getAcl()方法获取文件的AclEntry列表

　　setAcl()方法设置文件的AclEntry列表

（1）读取文件e:/test1.txt的ACL条目

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.AclEntry;
import java.nio.file.attribute.AclEntryPermission;
import java.nio.file.attribute.AclFileAttributeView;
import java.util.List;
import java.util.Set;

public class Main {
  public static void main(String[] args) {

    Path path = Paths.get("e:/test1.txt");
    AclFileAttributeView aclView = Files.getFileAttributeView(path,
        AclFileAttributeView.class);
    if (aclView == null) {
      System.out.format("ACL view is not supported.%n");
      return;
    }
    try {
      List<AclEntry> aclEntries = aclView.getAcl();
      for (AclEntry entry : aclEntries) {
        System.out.format("Principal: %s%n", entry.principal());
        System.out.format("Type: %s%n", entry.type());
        System.out.format("Permissions are:%n");

        Set<AclEntryPermission> permissions = entry.permissions();
        for (AclEntryPermission p : permissions) {
          System.out.format("%s %n", p);
        }

      }
    } catch (IOException e) {
      e.printStackTrace();
    }

  }
}

输出结果为

Principal: BUILTIN\Administrators (Alias)
Type: ALLOW
Permissions are:
WRITE_DATA
WRITE_OWNER
APPEND_DATA
SYNCHRONIZE
WRITE_ATTRIBUTES
EXECUTE
READ_DATA
DELETE_CHILD
READ_ATTRIBUTES
WRITE_NAMED_ATTRS
WRITE_ACL
DELETE
READ_ACL
READ_NAMED_ATTRS
Principal: NT AUTHORITY\SYSTEM (Well-known group)
Type: ALLOW
Permissions are:
WRITE_DATA
WRITE_OWNER
APPEND_DATA
SYNCHRONIZE
WRITE_ATTRIBUTES
EXECUTE
READ_DATA
DELETE_CHILD
READ_ATTRIBUTES
WRITE_NAMED_ATTRS
WRITE_ACL
DELETE
READ_ACL
READ_NAMED_ATTRS
Principal: NT AUTHORITY\Authenticated Users (Well-known group)
Type: ALLOW
Permissions are:
WRITE_DATA
READ_ATTRIBUTES
APPEND_DATA
WRITE_NAMED_ATTRS
SYNCHRONIZE
WRITE_ATTRIBUTES
EXECUTE
DELETE
READ_DATA
READ_ACL
READ_NAMED_ATTRS
Principal: BUILTIN\Users (Alias)
Type: ALLOW
Permissions are:
READ_ATTRIBUTES
SYNCHRONIZE
EXECUTE
READ_DATA
READ_ACL
READ_NAMED_ATTRS

（2）为指定用户添加新的ACL条目

e:/test1.txt为用户abc添加DATA_READ和DATA_ WRITE权限

import java.io.IOException;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.*;
import java.util.EnumSet;
import java.util.List;
import java.util.Set;

import static java.nio.file.attribute.AclEntryPermission.READ_DATA;
import static java.nio.file.attribute.AclEntryPermission.WRITE_DATA;

public class Main {
  public static void main(String[] args) {

    Path path = Paths.get("e:/test1.txt");
    AclFileAttributeView aclView = Files.getFileAttributeView(path,
        AclFileAttributeView.class);
    if (aclView == null) {
      System.out.format("ACL view is not supported.%n");
      return;
    }
    try {

      UserPrincipal bRiceUser = FileSystems.getDefault()
          .getUserPrincipalLookupService().lookupPrincipalByName("abc");

      Set<AclEntryPermission> permissions = EnumSet.of(READ_DATA, WRITE_DATA);

      AclEntry.Builder builder = AclEntry.newBuilder();
      builder.setPrincipal(bRiceUser);
      builder.setType(AclEntryType.ALLOW);
      builder.setPermissions(permissions);
      AclEntry newEntry = builder.build();

      List<AclEntry> aclEntries = aclView.getAcl();

      aclEntries.add(newEntry);

      aclView.setAcl(aclEntries);
    }catch (IOException e){
      e.printStackTrace();
    }
  }
}

输出结果比刚才多了

Principal: hkgi-PC\abc (User)
Type: ALLOW
Permissions are:
WRITE_DATA
READ_DATA

3.POSIX文件权限

UNIX支持POSIX标准文件属性

PosixFilePermission枚举类型定义九个常量，每个权限组件一个。

九个常数命名为X_Y，其中X是OWNER，GROUP和OTHERS，Y是READ，WRITE和EXECUTE。

PosixFilePermissions的toString()方法将一组PosixFilePermission枚举常量转换为rwxrwxrwx形式的字符串

PosixFileAttributeView的setPermissions()方法用来设置权限

（1）输出/www/test1.txt的权限

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.*;
import java.util.Set;

public class Main {
  public static void main(String[] args) {

    Path path = Paths.get("/www/test1.txt");
    PosixFileAttributeView posixView = Files.getFileAttributeView(path,
        PosixFileAttributeView.class);
    try{
      PosixFileAttributes attribs = posixView.readAttributes();
      Set<PosixFilePermission> permissions = attribs.permissions();
      // Convert the file permissions into the rwxrwxrwx string form
      String rwxFormPermissions = PosixFilePermissions.toString(permissions);
      // Print the permissions
      System.out.println(rwxFormPermissions);
    }catch (IOException e){
      e.printStackTrace();
    }

  }
}

输出结果

rw-r--r--

（2）读取和更新名为test的文件权限

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.*;
import java.util.EnumSet;
import java.util.Set;

import static java.nio.file.attribute.PosixFilePermission.*;

public class Main {
  public static void main(String[] args) {

    Path path = Paths.get("/www/test1.txt");
    PosixFileAttributeView posixView = Files.getFileAttributeView(path,
        PosixFileAttributeView.class);

    if (posixView == null) {
      System.out.format("POSIX attribute view is not supported%n.");
      return;
    }
    System.out.println("old:");
    readPermissions(posixView);
    updatePermissions(posixView);
    System.out.println("new:");
    readPermissions(posixView);

  }

  public static void readPermissions(PosixFileAttributeView posixView) {
    try{
      PosixFileAttributes attribs;
      attribs = posixView.readAttributes();
      Set<PosixFilePermission> permissions = attribs.permissions();
      // Convert the set of posix file permissions into rwxrwxrwx form
      String rwxFormPermissions = PosixFilePermissions.toString(permissions);
      System.out.println(rwxFormPermissions);
    }catch (IOException e){
      e.printStackTrace();
    }

  }
  public static void updatePermissions(PosixFileAttributeView posixView) {
    try {
      Set<PosixFilePermission> permissions = EnumSet.of(OWNER_READ, OWNER_WRITE,OWNER_EXECUTE,
          GROUP_READ,GROUP_WRITE);
      posixView.setPermissions(permissions);
      System.out.println("Permissions set successfully.");
    }catch (IOException e){
      e.printStackTrace();
    }
  }
}

输出结果

old:
rw-r-----
Permissions set successfully.
new:
rwxrw----

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