java 如何為文件及文件夾添加權限

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java 為文件及文件夾添加權限

/**
 * 增加權限，使路徑可上傳文件
 */
public static void addChmod777(String filePath) throws IOException {
	if (!System.getProperty("os.name").startsWith("Win")) {
		String cmdGrant = "chmod 777 " + filePath;
		BaseLogMethod.logInfo(TAG, "File Augmentation after Moving:" + cmdGrant);
		Runtime.getRuntime().exec(cmdGrant);
	}
}
/**
 * 增加權限，使路徑及子路徑都有權限
 */
public static void addRChmod777(String filePath) throws IOException {
	if (!System.getProperty("os.name").startsWith("Win")) {
		String cmdGrant = "chmod -R 777 " + filePath;
		BaseLogMethod.logInfo(TAG, ".addRChmod777: File Augmentation after Moving:" + cmdGrant);
		Runtime.getRuntime().exec(cmdGrant);
	}
}

java 修改文件所有者及其權限

1.設置所有者

管理文件所有者

Files.getOwner()和Files.setOwner()方法

要使用UserPrincipal來管理文件的所有者

（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();
        }
    }
}

輸出

查看文件詳細信息

2.ACL文件權限

Windows上支持ACL類型文件屬性

使用AclFileAttributeView的

  • getAcl()方法獲取文件的AclEntry列表
  • setAcl()方法設置文件的AclEntry列表

（1）讀取文件e:/test1.txt的ACL條目

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();
        }
    }
}

輸出結果為

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）為指定用戶添加新的ACL條目

e:/test1.txt為用戶abc添加DATA_READ和DATA_ WRITE權限

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();
        }
    }
}

輸出結果比剛才多瞭

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

3.POSIX文件權限

UNIX支持POSIX標準文件屬性

PosixFilePermission枚舉類型定義九個常量，每個權限組件一個。

九個常數命名為X_Y，其中X是OWNER，GROUP和OTHERS，Y是READ，WRITE和EXECUTE。

  • PosixFilePermissions的toString()方法將一組PosixFilePermission枚舉常量轉換為rwxrwxrwx形式的字符串
  • PosixFileAttributeView的setPermissions()方法用來設置權限

（1）輸出/www/test1.txt的權限

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();
        }
    }
}

輸出結果

rw-r–r–

（2）讀取和更新名為test的文件權限

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();
        }
    }
}

輸出結果

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

以上為個人經驗，希望能給大傢一個參考，也希望大傢多多支持WalkonNet。

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