如何获取jar文件内的文件夹路径？

Question

好的，所以在 IDE 中它运行得很好，并表示该文件存在，但是一旦我将其打包到 jar 中，此代码：

File levelFolder = new File(getClass().getResource("data/level").getPath()); 
System.out.println("exists = " + levelFolder.exists());

表示该文件夹不存在。知道为什么吗？

编辑：

jar 文件列表。

G:\java>jar tvf phantasyblade.jar
  6574 Wed Nov 10 22:36:34 PST 2010 META-INF/MANIFEST.MF
  6334 Wed Nov 10 22:36:34 PST 2010 META-INF/CYPRI.SF
   992 Wed Nov 10 22:36:34 PST 2010 META-INF/CYPRI.RSA
     0 Wed Nov 10 22:31:32 PST 2010 META-INF/
   717 Mon Nov 08 00:08:30 PST 2010 Switch.class
   935 Wed Nov 10 22:21:14 PST 2010 Sword1.class
   803 Tue Nov 09 13:42:38 PST 2010 SwordBlock.class
  2674 Tue Nov 09 13:42:38 PST 2010 Thing.class
     0 Wed Nov 10 22:32:56 PST 2010 data/
     0 Wed Nov 10 22:32:56 PST 2010 data/audio/
108669 Mon Nov 30 22:32:02 PST 2009 data/audio/boss1.ogg
 30866 Wed Nov 25 13:40:12 PST 2009 data/audio/edie.wav
 11440 Wed Dec 02 15:22:00 PST 2009 data/audio/ehit.wav
191532 Fri Apr 16 07:32:46 PDT 2010 data/audio/itemget.wav
154856 Mon Nov 30 21:55:18 PST 2009 data/audio/map1.ogg
 18572 Wed Aug 19 02:16:30 PDT 2009 data/audio/pdie.wav
 30924 Wed Dec 02 15:02:54 PST 2009 data/audio/pget.wav
 10044 Wed Aug 19 02:13:52 PDT 2009 data/audio/phit.wav
 24920 Wed Dec 02 15:08:44 PST 2009 data/audio/plife.wav
 17399 Mon Aug 24 17:40:00 PDT 2009 data/audio/sword.wav
 71946 Mon Nov 30 22:36:08 PST 2009 data/audio/title.ogg
     0 Wed Nov 10 22:32:56 PST 2010 data/graphics/
  5486 Mon Dec 07 23:15:46 PST 2009 data/graphics/alienzaku1.png
  1372 Mon Dec 14 02:05:44 PST 2009 data/graphics/ammo15.png
   888 Wed Nov 10 20:07:38 PST 2010 data/graphics/block.png
  1841 Mon Dec 07 16:50:00 PST 2009 data/graphics/bluegem.png
101871 Mon Dec 07 22:59:30 PST 2009 data/graphics/boss1.png
  9206 Mon Dec 14 13:21:26 PST 2009 data/graphics/bossblock1.png
   280 Tue Nov 18 08:13:44 PST 2008 data/graphics/bullet.png
  2831 Wed Dec 16 14:11:30 PST 2009 data/graphics/chargeshot.png
   277 Tue Nov 18 16:12:32 PST 2008 data/graphics/ebullet.png
  1928 Wed Dec 16 14:05:14 PST 2009 data/graphics/echargeshot.png
  3573 Wed Dec 02 15:07:06 PST 2009 data/graphics/ehealth.png
  6158 Mon Dec 14 22:17:06 PST 2009 data/graphics/gameover.png
  1594 Mon Dec 07 16:49:32 PST 2009 data/graphics/greengem.png
  5279 Mon Dec 07 16:49:44 PST 2009 data/graphics/health.png
  5591 Wed Dec 16 22:37:20 PST 2009 data/graphics/hexcontainer.png
 23037 Tue Dec 15 13:03:32 PST 2009 data/graphics/hud.png
  8173 Thu Dec 03 00:22:14 PST 2009 data/graphics/hud1.png
   280 Tue Nov 18 08:13:44 PST 2008 data/graphics/hudbullet.png
   606 Wed Dec 02 04:58:50 PST 2009 data/graphics/hudgem.png
  3527 Wed Dec 02 15:07:02 PST 2009 data/graphics/hudhealth.png
 13726 Wed Dec 16 14:40:36 PST 2009 data/graphics/hunter.png
   666 Wed Nov 10 21:09:54 PST 2010 data/graphics/key.png
 11010 Thu Nov 26 11:14:02 PST 2009 data/graphics/levelclear.png
  1306 Wed Nov 10 20:08:42 PST 2010 data/graphics/lockedblock.png
  2340 Mon Dec 14 16:32:26 PST 2009 data/graphics/mapsword.png
  1448 Wed Nov 10 20:20:58 PST 2010 data/graphics/moveblock.png
  1660 Sun Nov 07 12:54:42 PST 2010 data/graphics/neblock.png
 30258 Mon Dec 07 16:50:28 PST 2009 data/graphics/neoscout1.png
  9569 Mon Dec 07 23:25:08 PST 2009 data/graphics/player.png
  5903 Mon Dec 07 16:36:02 PST 2009 data/graphics/playerdead.png
  3910 Fri Apr 16 07:23:12 PDT 2010 data/graphics/playerget.png
 11966 Mon Dec 14 00:07:32 PST 2009 data/graphics/playerroll.png
  1316 Wed Nov 10 20:12:18 PST 2010 data/graphics/stepswitch.png
  2972 Mon Dec 07 23:22:08 PST 2009 data/graphics/sword.png
  2972 Mon Dec 07 23:22:08 PST 2009 data/graphics/sword2.png
  1450 Sun Nov 07 12:51:22 PST 2010 data/graphics/swordblock.png
 10860 Fri Apr 16 07:29:08 PDT 2010 data/graphics/swordget.png
289531 Sun Dec 13 00:28:56 PST 2009 data/graphics/tilemap.png
134821 Tue Dec 15 00:28:38 PST 2009 data/graphics/title.png
  6044 Wed Nov 25 17:39:50 PST 2009 data/graphics/win.png
  1511 Wed Nov 10 10:38:02 PST 2010 data/graphics/zbutton.png
     0 Wed Nov 10 22:32:56 PST 2010 data/level/
  2132 Wed Nov 10 20:59:58 PST 2010 data/level/map1.lv
   949 Wed Nov 10 22:23:24 PST 2010 data/level/map2.lv
   813 Wed Nov 10 21:07:10 PST 2010 data/level/map3.lv
  1370 Sun Nov 07 12:37:42 PST 2010 Ammo15.class
  1369 Sun Nov 07 12:37:42 PST 2010 BlueGem.class
  4789 Sun Nov 07 18:26:34 PST 2010 Boss1.class
   825 Mon Nov 08 05:34:02 PST 2010 BossBlock1.class
  6159 Sun Nov 07 18:30:54 PST 2010 Bullet.class
  3487 Sun Nov 07 12:37:42 PST 2010 ChargeShot.class
  8425 Wed Nov 10 22:01:54 PST 2010 Enemy.class
  5837 Wed Nov 10 22:01:54 PST 2010 Enemy1.class
  6164 Wed Nov 10 22:01:54 PST 2010 Enemy2.class
  4902 Sun Nov 07 18:26:34 PST 2010 Enemy3.class
  7780 Sun Nov 07 18:26:34 PST 2010 Enemy4.class
 30632 Wed Nov 10 22:19:38 PST 2010 Game1.class
   656 Tue Nov 09 13:42:32 PST 2010 GrabBlock1.class
  1372 Sun Nov 07 12:37:42 PST 2010 GreenGem.class
  1074 Tue Nov 09 13:42:34 PST 2010 HexContainer.class
  1372 Sun Nov 07 12:37:42 PST 2010 Item.class
   811 Wed Nov 10 20:13:46 PST 2010 Key.class
   609 Mon Nov 08 20:10:04 PST 2010 Level.class
  1368 Sun Nov 07 12:37:42 PST 2010 Life.class
   656 Wed Nov 10 16:41:50 PST 2010 LockedBlock.class
  2004 Sun Nov 07 18:26:34 PST 2010 Map.class
   751 Tue Nov 09 13:42:36 PST 2010 NEBlock.class
   659 Tue Nov 09 13:42:36 PST 2010 NormalBlock1.class
 18722 Wed Nov 10 22:02:28 PST 2010 Player.class
  1726 Mon Nov 08 05:34:06 PST 2010 StepSwitch.class

G:\java>

Answer 1

一般来说，这是因为您 getClass() 的类位于 com.something.app 包中，因此使用相对路径，您的数据必须位于 com/something/app/data/level 中。否则使用绝对路径。

查看 jarfile 中的内容：

jar tvf myapp.jar

[好吧，经过大量来回和一些测试]...

jcomeau@intrepid:/tmp$ cat test.java; java -cp test.jar test; jar tvf test.jar
import java.io.*;
public class test {
 public static void main(String[] args) {
  //System.out.println(test.class.getResource("data/level"));
  try {
   System.out.println(new File(test.class.getResource("data/level").getPath()));
   System.out.println(test.class.getResourceAsStream("data/level/test").read());
  } catch (Exception whatever) {
   System.err.println("error: " + whatever);
  }
 }
}
file:/tmp/test.jar!/data/level
116
     0 Thu Nov 11 00:36:14 PST 2010 META-INF/
    40 Thu Nov 11 00:36:14 PST 2010 META-INF/MANIFEST.MF
  1362 Thu Nov 11 00:35:46 PST 2010 test.class
     0 Wed Nov 10 07:53:18 PST 2010 data/
     0 Wed Nov 10 07:53:28 PST 2010 data/level/
     5 Wed Nov 10 07:53:28 PST 2010 data/level/test
jcomeau@intrepid:/tmp$ 

我太累了，无法继续，但 main() 打印 116，这是“的 ASCII 值” t”，read() 读取第一个字节的结果。这应该足以证明 getResourceAsStream() 将使您能够访问您的资源。也应该有一种方法可以使用 File() 来完成此操作，但是返回的路径对于“！”来说很奇怪将 jar 文件的路径与 jar 文件内部的路径分开。我以前从未处理过这个问题。

Answer 2

Enumeration<URL> resources = getClass().getClassLoader().getResources("data/level");
System.out.println("exists = " + resources.hasMoreElements());