How to set File Permission in Java? Here is a simple example of setting up file permission on any provided file.
If you are part of Operations business unit of any company then it’s very important to automate deployment workflow, analysis workflow and so on.
Sometimes your Java program exit with exception if you would try to execute some command and somehow for given file you don’t have permission to execute script file.
In our case, it’s Crunchify.sh file.
Here is a simple Java Program which shows how to setup File Permission on any given file.
CrunchifySetFilePermission.java
package crunchify.com.java.tutorials;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.file.attribute.PosixFilePermission;
import java.util.HashSet;
import java.util.Set;
import java.io.File;
/**
* @author Crunchify.com
* In Java how to Set File Permission on a File using PosixFilePermission? Understanding chmod command.
*/
public class CrunchifySetFilePermission {
public static void main(String[] args) {
// File class: An abstract representation of file and directory pathnames.
// User interfaces and operating systems use system-dependent pathname strings to name files and directories.
// This class presents an abstract, system-independent view of hierarchical pathnames.
File file = new File("/Users/app/Download/crunchify.txt");
/* -------------------------- Set Permission: 455 ----------------------- */
// A convenience method to set the owner's execute permission for this abstract pathname.
// On some platforms it may be possible to start the Java virtual machine with special privileges that allow it to execute files that are not marked executable.
file.setExecutable(false); // public boolean setExecutable(boolean executable)
// A convenience method to set the owner's read permission for this abstract pathname.
// On some platforms it may be possible to start the Java virtual machine with special privileges that allow it to read files that are marked as unreadable.
file.setReadable(false);
// A convenience method to set the owner's write permission for this abstract pathname.
// On some platforms it may be possible to start the Java virtual machine with special privileges that allow it to modify files that disallow write operations.
file.setWritable(true);
/* -------------------------- Set Permission: 777 ----------------------- */
// public boolean setExecutable(boolean executable, boolean ownerOnly)
file.setExecutable(true, false);
file.setReadable(true, false);
file.setWritable(true, false);
// using PosixFilePermission to set file permissions 777. PosixFilePermission - defines the bits for use with the permissions attribute.
// The PosixFilePermissions class defines methods for manipulating set of permissions
// HashSet: Constructs a new, empty set; the backing HashMap instance has default initial capacity (16) and load factor (0.75).
Set<PosixFilePermission> crunchifyPermissions = new HashSet<PosixFilePermission>();
// add() Adds the specified element to this set if it is not already present (optional operation).
// More formally, adds the specified element e to this set if the set contains no element e2 such that Objects.equals(e, e2).
// If this set already contains the element, the call leaves the set unchanged and returns false.
// In combination with the restriction on constructors, this ensures that sets never contain duplicate elements.
/* -------------------------- OWNER Permissions ----------------------- */
// Read permission, owner.
crunchifyPermissions.add(PosixFilePermission.OWNER_READ);
// Write permission, owner.
crunchifyPermissions.add(PosixFilePermission.OWNER_WRITE);
// Execute/search permission, owner.
crunchifyPermissions.add(PosixFilePermission.OWNER_EXECUTE);
/* -------------------------- GROUP Permissions ----------------------- */
// PosixFilePermission: Defines the bits for use with the permissions attribute.
// The PosixFilePermissions class defines methods for manipulating set of permissions.
// Read permission, group.
crunchifyPermissions.add(PosixFilePermission.GROUP_READ);
// Write permission, group.
crunchifyPermissions.add(PosixFilePermission.GROUP_WRITE);
// Execute/search permission, group.
crunchifyPermissions.add(PosixFilePermission.GROUP_EXECUTE);
/* -------------------------- OTHERS Permissions ----------------------- */
// Read permission, others.
crunchifyPermissions.add(PosixFilePermission.OTHERS_READ);
// Write permission, others.
crunchifyPermissions.add(PosixFilePermission.OTHERS_WRITE);
// Execute/search permission, others.
crunchifyPermissions.add(PosixFilePermission.OTHERS_EXECUTE);
try {
// Sets a file's POSIX permissions.
// The path parameter is associated with a FileSystem that supports the PosixFileAttributeView. This attribute view provides access to file
// attributes commonly associated with files on file systems used by operating systems that implement the Portable Operating System Interface (POSIX) family of standards.
Files.setPosixFilePermissions(Paths.get("/Users/app/Download/crunchify.sh"), crunchifyPermissions);
// Paths: This class consists exclusively of static methods that return a Path by converting a path string or URI.
System.out.println("File permission set successfully...");
} catch (IOException e) {
// Signals that an I/O exception of some sort has occurred. This class is the general class of exceptions produced by failed or interrupted I/O operations.
e.printStackTrace();
}
}
}
Just run above Java Program and you should see permission of file Crunchify.sh as below.
-rwxrwxrwx 1 crunchify crunchify 65 Jun 23 14:42 crunchify.sh
If you remove or comment out below 3 files then it will change permission as below:
// crunchifyPermissions.add(PosixFilePermission.OTHERS_READ); // crunchifyPermissions.add(PosixFilePermission.OTHERS_WRITE); // crunchifyPermissions.add(PosixFilePermission.OTHERS_EXECUTE);
-rwxrwx--- 1 crunchify crunchify 65 Jun 23 14:42 crunchify.sh
Let’s understand Linux File Permissions:
Here is a list of all permissions:
100 ---x------ 101 ---x-----x 102 ---x----w- 103 ---x----wx 104 ---x---r-- 105 ---x---r-x 106 ---x---rw- 107 ---x---rwx 110 ---x--x--- 111 ---x--x--x 112 ---x--x-w- 113 ---x--x-wx 114 ---x--xr-- 115 ---x--xr-x 116 ---x--xrw- 117 ---x--xrwx 120 ---x-w---- 121 ---x-w---x 122 ---x-w--w- 123 ---x-w--wx 124 ---x-w-r-- 125 ---x-w-r-x 126 ---x-w-rw- 127 ---x-w-rwx 130 ---x-wx--- 131 ---x-wx--x 132 ---x-wx-w- 133 ---x-wx-wx 134 ---x-wxr-- 135 ---x-wxr-x 136 ---x-wxrw- 137 ---x-wxrwx 140 ---xr----- 141 ---xr----x 142 ---xr---w- 143 ---xr---wx 144 ---xr--r-- 145 ---xr--r-x 146 ---xr--rw- 147 ---xr--rwx 150 ---xr-x--- 151 ---xr-x--x 152 ---xr-x-w- 153 ---xr-x-wx 154 ---xr-xr-- 155 ---xr-xr-x 156 ---xr-xrw- 157 ---xr-xrwx 160 ---xrw---- 161 ---xrw---x 162 ---xrw--w- 163 ---xrw--wx 164 ---xrw-r-- 165 ---xrw-r-x 166 ---xrw-rw- 167 ---xrw-rwx 170 ---xrwx--- 171 ---xrwx--x 172 ---xrwx-w- 173 ---xrwx-wx 174 ---xrwxr-- 175 ---xrwxr-x 176 ---xrwxrw- 177 ---xrwxrwx 226 --w--w-rw- 227 --w--w-rwx 241 --w-r----x 242 --w-r---w- 243 --w-r---wx 244 --w-r--r-- 245 --w-r--r-x 246 --w-r--rw- 247 --w-r--rwx 250 --w-r-x--- 251 --w-r-x--x 252 --w-r-x-w- 253 --w-r-x-wx 254 --w-r-xr-- 255 --w-r-xr-x 256 --w-r-xrw- 257 --w-r-xrwx 260 --w-rw---- 261 --w-rw---x 262 --w-rw--w- 263 --w-rw--wx 264 --w-rw-r-- 265 --w-rw-r-x 266 --w-rw-rw- 267 --w-rw-rwx 270 --w-rwx--- 271 --w-rwx--x 272 --w-rwx-w- 273 --w-rwx-wx 274 --w-rwxr-- 275 --w-rwxr-x 276 --w-rwxrw- 277 --w-rwxrwx 300 --wx------ 301 --wx-----x 302 --wx----w- 303 --wx----wx 304 --wx---r-- 305 --wx---r-x 306 --wx---rw- 307 --wx---rwx 310 --wx--x--- 311 --wx--x--x 312 --wx--x-w- 313 --wx--x-wx 314 --wx--xr-- 315 --wx--xr-x 316 --wx--xrw- 317 --wx--xrwx 320 --wx-w---- 321 --wx-w---x 322 --wx-w--w- 323 --wx-w--wx 324 --wx-w-r-- 325 --wx-w-r-x 326 --wx-w-rw- 327 --wx-w-rwx 330 --wx-wx--- 331 --wx-wx--x 332 --wx-wx-w- 333 --wx-wx-wx 334 --wx-wxr-- 335 --wx-wxr-x 336 --wx-wxrw- 337 --wx-wxrwx 340 --wxr----- 341 --wxr----x 342 --wxr---w- 343 --wxr---wx 344 --wxr--r-- 345 --wxr--r-x 346 --wxr--rw- 347 --wxr--rwx 350 --wxr-x--- 351 --wxr-x--x 352 --wxr-x-w- 353 --wxr-x-wx 354 --wxr-xr-- 355 --wxr-xr-x 356 --wxr-xrw- 357 --wxr-xrwx 360 --wxrw---- 361 --wxrw---x 362 --wxrw--w- 363 --wxrw--wx 364 --wxrw-r-- 365 --wxrw-r-x 366 --wxrw-rw- 367 --wxrw-rwx 370 --wxrwx--- 371 --wxrwx--x 372 --wxrwx-w- 373 --wxrwx-wx 374 --wxrwxr-- 375 --wxrwxr-x 376 --wxrwxrw- 377 --wxrwxrwx 400 -r-------- 401 -r-------x 402 -r------w- 403 -r------wx 404 -r-----r-- 405 -r-----r-x 406 -r-----rw- 407 -r-----rwx 410 -r----x--- 411 -r----x--x 412 -r----x-w- 413 -r----x-wx 414 -r----xr-- 415 -r----xr-x 416 -r----xrw- 417 -r----xrwx 420 -r---w---- 421 -r---w---x 422 -r---w--w- 423 -r---w--wx 424 -r---w-r-- 425 -r---w-r-x 426 -r---w-rw- 427 -r---w-rwx 430 -r---wx--- 431 -r---wx--x 432 -r---wx-w- 433 -r---wx-wx 434 -r---wxr-- 435 -r---wxr-x 436 -r---wxrw- 437 -r---wxrwx 440 -r--r----- 441 -r--r----x 442 -r--r---w- 443 -r--r---wx 444 -r--r--r-- 445 -r--r--r-x 446 -r--r--rw- 447 -r--r--rwx 450 -r--r-x--- 451 -r--r-x--x 452 -r--r-x-w- 453 -r--r-x-wx 454 -r--r-xr-- 455 -r--r-xr-x 456 -r--r-xrw- 457 -r--r-xrwx 460 -r--rw---- 461 -r--rw---x 462 -r--rw--w- 463 -r--rw--wx 464 -r--rw-r-- 465 -r--rw-r-x 466 -r--rw-rw- 467 -r--rw-rwx 470 -r--rwx--- 471 -r--rwx--x 472 -r--rwx-w- 473 -r--rwx-wx 474 -r--rwxr-- 475 -r--rwxr-x 476 -r--rwxrw- 477 -r--rwxrwx 500 -r-x------ 501 -r-x-----x 502 -r-x----w- 503 -r-x----wx 504 -r-x---r-- 505 -r-x---r-x 506 -r-x---rw- 507 -r-x---rwx 510 -r-x--x--- 511 -r-x--x--x 512 -r-x--x-w- 513 -r-x--x-wx 514 -r-x--xr-- 515 -r-x--xr-x 516 -r-x--xrw- 517 -r-x--xrwx 520 -r-x-w---- 521 -r-x-w---x 522 -r-x-w--w- 523 -r-x-w--wx 524 -r-x-w-r-- 525 -r-x-w-r-x 526 -r-x-w-rw- 527 -r-x-w-rwx 530 -r-x-wx--- 531 -r-x-wx--x 532 -r-x-wx-w- 533 -r-x-wx-wx 534 -r-x-wxr-- 535 -r-x-wxr-x 536 -r-x-wxrw- 537 -r-x-wxrwx 540 -r-xr----- 541 -r-xr----x 542 -r-xr---w- 543 -r-xr---wx 544 -r-xr--r-- 545 -r-xr--r-x 546 -r-xr--rw- 547 -r-xr--rwx 550 -r-xr-x--- 551 -r-xr-x--x 552 -r-xr-x-w- 553 -r-xr-x-wx 554 -r-xr-xr-- 555 -r-xr-xr-x 556 -r-xr-xrw- 557 -r-xr-xrwx 560 -r-xrw---- 561 -r-xrw---x 562 -r-xrw--w- 563 -r-xrw--wx 564 -r-xrw-r-- 565 -r-xrw-r-x 566 -r-xrw-rw- 567 -r-xrw-rwx 570 -r-xrwx--- 571 -r-xrwx--x 572 -r-xrwx-w- 573 -r-xrwx-wx 574 -r-xrwxr-- 575 -r-xrwxr-x 576 -r-xrwxrw- 577 -r-xrwxrwx 600 -rw------- 601 -rw------x 602 -rw-----w- 603 -rw-----wx 604 -rw----r-- 605 -rw----r-x 606 -rw----rw- 607 -rw----rwx 610 -rw---x--- 611 -rw---x--x 612 -rw---x-w- 613 -rw---x-wx 614 -rw---xr-- 615 -rw---xr-x 616 -rw---xrw- 617 -rw---xrwx 620 -rw--w---- 621 -rw--w---x 622 -rw--w--w- 623 -rw--w--wx 624 -rw--w-r-- 625 -rw--w-r-x 626 -rw--w-rw- 627 -rw--w-rwx 630 -rw--wx--- 631 -rw--wx--x 632 -rw--wx-w- 633 -rw--wx-wx 634 -rw--wxr-- 635 -rw--wxr-x 636 -rw--wxrw- 637 -rw--wxrwx 640 -rw-r----- 641 -rw-r----x 642 -rw-r---w- 643 -rw-r---wx 644 -rw-r--r-- 645 -rw-r--r-x 646 -rw-r--rw- 647 -rw-r--rwx 650 -rw-r-x--- 651 -rw-r-x--x 652 -rw-r-x-w- 653 -rw-r-x-wx 654 -rw-r-xr-- 655 -rw-r-xr-x 656 -rw-r-xrw- 657 -rw-r-xrwx 660 -rw-rw---- 661 -rw-rw---x 662 -rw-rw--w- 663 -rw-rw--wx 664 -rw-rw-r-- 665 -rw-rw-r-x 666 -rw-rw-rw- 667 -rw-rw-rwx 670 -rw-rwx--- 671 -rw-rwx--x 672 -rw-rwx-w- 673 -rw-rwx-wx 674 -rw-rwxr-- 675 -rw-rwxr-x 676 -rw-rwxrw- 677 -rw-rwxrwx 700 -rwx------ 701 -rwx-----x 702 -rwx----w- 703 -rwx----wx 704 -rwx---r-- 705 -rwx---r-x 706 -rwx---rw- 707 -rwx---rwx 710 -rwx--x--- 711 -rwx--x--x 712 -rwx--x-w- 713 -rwx--x-wx 714 -rwx--xr-- 715 -rwx--xr-x 716 -rwx--xrw- 717 -rwx--xrwx 720 -rwx-w---- 721 -rwx-w---x 722 -rwx-w--w- 723 -rwx-w--wx 724 -rwx-w-r-- 725 -rwx-w-r-x 726 -rwx-w-rw- 727 -rwx-w-rwx 730 -rwx-wx--- 731 -rwx-wx--x 732 -rwx-wx-w- 733 -rwx-wx-wx 734 -rwx-wxr-- 735 -rwx-wxr-x 736 -rwx-wxrw- 737 -rwx-wxrwx 740 -rwxr----- 741 -rwxr----x 742 -rwxr---w- 743 -rwxr---wx 744 -rwxr--r-- 745 -rwxr--r-x 746 -rwxr--rw- 747 -rwxr--rwx 750 -rwxr-x--- 751 -rwxr-x--x 752 -rwxr-x-w- 753 -rwxr-x-wx 754 -rwxr-xr-- 755 -rwxr-xr-x 756 -rwxr-xrw- 757 -rwxr-xrwx 760 -rwxrw---- 761 -rwxrw---x 762 -rwxrw--w- 763 -rwxrw--wx 764 -rwxrw-r-- 765 -rwxrw-r-x 766 -rwxrw-rw- 767 -rwxrw-rwx 770 -rwxrwx--- 771 -rwxrwx--x 772 -rwxrwx-w- 773 -rwxrwx-wx 774 -rwxrwxr-- 775 -rwxrwxr-x 776 -rwxrwxrw- 777 -rwxrwxrwx
Let us know if you face any problem running above program.
The post In Java how to Set File Permission on a File using PosixFilePermission? Understanding chmod command appeared first on Crunchify.
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