java - java的Filestore类的方法supportsFileAttributeView(...)

Question

我尝试在我的环境中添加对 UserDefinedFileAttributeView 的支持。这就是我到目前为止所做的。我已将“user_xattr”选项添加到/etc/fstab 文件中:

# / was on /dev/sda3 during installation
UUID=9b1809de-d409-47ce-aee0-dd1e878b0bab /               ext4    errors=remount-ro,user_xattr  0       1
# /boot was on /dev/sda2 during installation
UUID=fd898890-17a0-423a-987e-9dc0a5008320 /boot           ext2    defaults        0       2
# /home was on /dev/sda5 during installation
UUID=439ea035-cac4-4801-9023-b1b1abb4ab9e /home           ext4    defaults,user_xattr        0       2
# swap was on /dev/sda1 during installation
UUID=a534b1c7-1a00-488f-92a8-a530b5d902ac none            swap    sw              0       0

像这样的简单代码:

for (FileStore store : fileSystem.getFileStores()) {
  boolean supported = store.supportsFileAttributeView(UserDefinedFileAttributeView.class);
  System.out.println(store.name() + " --- " + supported);
}

“/home”(/dev/sdar5) 的显示为:

/dev/sda5 --- true

但是如果我这样做:

FileStore store1 = Files.getFileStore((new File("/home")).toPath());
boolean supported1 = store1.supportsFileAttributeView(UserDefinedFileAttributeView.class);
System.out.println(store1.name() + " --- " + supported1);

我得到:

/dev/sda5 --- false 

这是为什么呢？我认为在这两种情况下都是“真实”的。 我的操作系统是 Linux Mint 17.2 Rafaela 64 位。

Answer 1

我发现，由于方法supportsFileAttributeView(UserDefinedFileAttributeView.class)返回false，所以UserDefinedFileAttributeView实际上是受支持的(可以使用、设置、检索...)。