英文:
How can I access a txt file with a relative path?
问题
我正在使用IntelliJ Idea，我尝试从项目的不同位置读取txt文件。我不想使用像C:/User/...这样的绝对路径，因为如果项目移动到其他位置，项目将无法正常工作。我不确定路径应该是什么样的。
英文:
I'm using IntelliJ Idea and I try to read a txt file from a different location in the project. I don't want to use an absolute path like C:/User/... because if the project is moved to a different location the project wouldn't work anymore. I'm not sure how the path should look like.
答案1
得分: 1
如果您使用相对路径，通常也意味着一旦更改目录结构，它将不再起作用。
示例（我假设这里是Windows）：
Java应用程序位于 C:\Tools。您正在使用相对路径（..\file.txt）。这将访问 C:\file.txt（.. 移动到上一级目录）。
如果您将该应用程序移动到 C:\Tools\JavaApp，它将不再工作，因为 ..\file.txt 现在指向 C:\Tools\file.txt）。
您有几个选项（我脑海中仅列出了三个选项；有多种方法可以实现您想要的效果）：
-
使用别名来访问文件。这里 是一些在Windows上可以工作的快捷方式列表（我假设您正在使用Windows）。例如：将文件保存到
%appdata%，它将始终保存到当前用户的应用数据文件夹。要在Java中将Windows快捷方式解析为绝对路径，请使用System.getenv("APPDATA")。 -
从程序的工作目录中读取文件
这可能是您使用相对路径时所指的：
Java应用程序的当前工作目录是从中运行程序的目录。这将要求您将要读取的文件放在与您的项目/jar文件相同的文件夹中，或者使用相对路径导航到文件的位置，例如您的工作目录中的子文件夹，您将在其中放置该文件。 -
使用 .properties 文件声明文件位置
您还可以从属性文件中读取文件位置，但只能在编译时更改路径。这里有 一篇关于如何使用 .properties 文件的文章。
英文:
If you are using relative Paths, this will generally also mean that it will not work anymore once you are changing directory structure.
Example (I am assuming Windows here):
The java-application resides C:\Tools . You are using a relative Path (..\file.txt). This would access C:\file.txt (.. moves up one directory).
If you moved the App to C:\Tools\JavaApp it wouldn't work anymore, since ..\file.txt now points to C:\Tools\file.txt).
You have several options (three just from the top of my head; there are multiple ways to do this) to achieve what you want:
-
Use an alias to access the file. Here is a list of windows-shortcuts that will work (I am assuming that you are using Windows). For example: Save the file to
%appdata%, and it will always save to the current user's appdata folder. To resolve the windows shortcut to an absolute path in Java, useSystem.getenv("APPDATA"). -
Read the file from the program's working directory
This is probably what you meant by using relative paths:
The current working directory of a java application is the directory the program is being run from. This will require you to place the file to be read in the same folder as your project/jar-file, or to use relative paths to navigate to the file's location, for example a sub-folder in your working directory where you would place the file. -
Use a .properties file to declare the file location
You could also read the file location from a properties file, however you can only change the path at compile time. Here's an article on how to use .properties-files.
答案2
得分: 1
参见 此链接
您可以像这样使用相对路径访问文件：
File file = new File("..\\..\\file.txt");
String fileAbsolutePath = file.getAbsolutePath();
提示：仅当文件嵌入到项目中时才有效。
英文:
See this
You can access files with relative path like this way:
File file = new File("..\\..\\file.txt");
String fileAbsolutePath = file.getAbsolutePath();
Hint: This only works if the file is embedded to the project.
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