/storage/sdcard， /sdcard， /mnt/sdcard 三者的区别

public static final String SDPATH = Environment .getExternalStorageDirectory().getAbsolutePath();
//获取外部存储的路径返回绝对路径的,其实就是你的SD卡的文件路径

/storage/sdcard
/sdcard
/mnt/sdcard

以上三者的区别？

/sdcard是/mnt/sdcard的符号链，指向/mnt/sdcard，

/storage/sdcard 是sdcard的分区……

/sdcard/: this is a symlink to...
/mnt/sdcard (Android < 4.0)
/storage/sdcard0 (Android 4.0+)

• /storage/emulated/0/: to my knowledge, this refers to the "emulated MMC" ("owner part"). Usually this is the internal one. The "0" stands for the user here, "0" is the first user aka device-owner. If you create additional users, this number will increment for each.
• /storage/emulated/legacy/ as before, but pointing to the part of the currently working user (for the owner, this would be a symlink to /storage/emulated/0/). So this path should bring every user to his "part".
• /sdcard/: According to a comment by Shywim, this is a symlink to...
  • /mnt/sdcard (Android < 4.0)
  • /storage/sdcard0 (Android 4.0+)
• /storage/sdcard0/: As there's no legacy pendant here (see comments below), the "0" in this case rather identifies the device (card) itself. One could, eventually, connect a card reader with another SDCard via OTG, which then would become /storage/sdcard1 (no proof for that, just a guess -- but I'd say a good one)

internal storage - Confused by the many locations of the virtual /sdcard/ - Android Enthusiasts Stack Exchange
http://android.stackexchange.com/questions/39542/confused-by-the-many-locations-of-the-virtual-sdcard