使用相对路径在JAR中读取文件 [英] Reading File In JAR using Relative Path

问题描述

我有一些需要我的程序读取的文本配置文件。我目前的代码是：

  protected File getConfigFile（）{
 URL url = getClass（）。getResource（wof 。文本）; 
返回新文件（url.getFile（）。replaceAll（％20，））; 
} 
  

当我在eclipse中本地运行它时，这是有效的，尽管我确实需要这样做黑客攻击路径名中的空间。配置文件与上述方法位于同一个包中。但是，当我将应用程序导出为jar时，我遇到了问题。 jar存在于共享的映射网络驱动器Z：上。当我从命令行运行应用程序时，我收到此错误：

java.io.FileNotFoundException：file：\ Z：\ apps\jar\apps。 jar！\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\我只想告诉java读取与当前类相同的目录中的文件。

谢谢，
Jonah

解决方案

当文件在jar中时，你不能使用文件类来表示它，因为它是一个 jar： URI。相反，URL类本身已经为您提供了 openStream（）读取内容的可能性。

或者你可以使用 getResourceAsStream（）而不是 getResource（）来快捷方式。

要获得BufferedReader（更容易使用，因为它有 readLine（）方法），请使用通常的流包装：

  InputStream configStream = getClass（）。getResourceAsStream（wof.txt）; 
 BufferedReader configReader = new BufferedReader（new InputStreamReader（configStream，UTF-8））; 
  

而不是UTF-8使用文件实际使用的编码（即您在编辑）。

---

另一点：即使你只有文件： URI，你不应该自己做文件转换的URL，而是使用 new File（url.toURI（））。这适用于其他有问题的角色。

I have some text configuration file that need to be read by my program. My current code is:

protected File getConfigFile() {
    URL url = getClass().getResource("wof.txt");
    return new File(url.getFile().replaceAll("%20", " "));
}

This works when I run it locally in eclipse, though I did have to do that hack to deal with the space in the path name. The config file is in the same package as the method above. However, when I export the application as a jar I am having problems with it. The jar exists on a shared, mapped network drive Z:. When I run the application from command line I get this error:

java.io.FileNotFoundException: file:\Z:\apps\jar\apps.jar!\vp\fsm\configs\wof.txt

How can I get this working? I just want to tell java to read a file in the same directory as the current class.

Thanks, Jonah

解决方案

When the file is inside a jar, you can't use the File class to represent it, since it is a jar: URI. Instead, the URL class itself already gives you with openStream() the possibility to read the contents.

Or you can shortcut this by using getResourceAsStream() instead of getResource().

To get a BufferedReader (which is easier to use, as it has a readLine() method), use the usual stream-wrapping:

InputStream configStream = getClass().getResourceAsStream("wof.txt");
BufferedReader configReader = new BufferedReader(new InputStreamReader(configStream, "UTF-8"));

Instead of "UTF-8" use the encoding actually used by the file (i.e. which you used in the editor).

---

Another point: Even if you only have file: URIs, you should not do the URL to File-conversion yourself, instead use new File(url.toURI()). This works for other problematic characters as well.

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