在Java中有时候会碰到一种情况，就是创建出来的目录或者文件，需要对别的用户也可读可写，这时候就需要修改创建的文件的权限，一般来说可以有不同的做法。

一种是直接在file本身上修改：

file.setWritable(true, false)
file.setReadable(true, false)

或者也可以自己实现，去控制不同的权限：

public static void changePermission(File file) {
  Set<PosixFilePermission> perms = new HashSet<>();
  perms.add(PosixFilePermission.OWNER_WRITE);
  perms.add(PosixFilePermission.OWNER_READ);
  perms.add(PosixFilePermission.GROUP_WRITE);
  perms.add(PosixFilePermission.GROUP_READ);
  perms.add(PosixFilePermission.OTHERS_WRITE);
  perms.add(PosixFilePermission.OTHERS_READ);
  try {
    Files.setPosixFilePermissions(file.toPath(), perms);
  } catch (IOException e) {
    throw new UncheckedIOException(e);
  }
}

写个测试：

@Test
public void testChangePermission() throws IOException {
  String basePath = System.getProperty("java.io.tmpdir", "/tmp");
  String pattern = basePath.endsWith("/") ? "%s%s" : "%s/%s";
  String testDir = String.format(pattern, basePath, UUIDUtils.random());
  File file = new File(testDir);
  try {
    Assert.assertTrue(file.mkdirs());
    Set<PosixFilePermission> permissions = getPosixFilePermissions(testDir);
    System.out.println(PosixFilePermissions.toString(permissions));
    FileUtils.changePermission(file);
    permissions = getPosixFilePermissions(testDir);
    System.out.println(PosixFilePermissions.toString(permissions));
    Assert.assertTrue(permissions.contains(PosixFilePermission.OWNER_WRITE));
    Assert.assertTrue(permissions.contains(PosixFilePermission.OWNER_READ));
    Assert.assertTrue(permissions.contains(PosixFilePermission.GROUP_WRITE));
    Assert.assertTrue(permissions.contains(PosixFilePermission.GROUP_READ));
    Assert.assertTrue(permissions.contains(PosixFilePermission.OTHERS_WRITE));
    Assert.assertTrue(permissions.contains(PosixFilePermission.OTHERS_READ));
  } finally {
    Assert.assertTrue(file.delete());
  }
}

private Set<PosixFilePermission> getPosixFilePermissions(String testDir) throws IOException {
  PosixFileAttributeView posixView = Files.getFileAttributeView(Paths.get(testDir), PosixFileAttributeView.class);
  return posixView.readAttributes().permissions();
}

这篇文章也有详细的介绍：https://stackoverflow.com/questions/14325641/create-folders-programmatically-along-with-permissions-using-java-to-save-conten

扫码手机观看或分享：