Java 移动到下一级目录
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Moving to a directory one level down
提问by sutoL
Is it possible to move to a directory one level down in Java?
是否可以在 Java 中移动到下一级目录？
For example in command prompt:
例如在命令提示符中：
C:\Users\foo\
I can use cd..to go to:
我可以cd..用来去：
C:\Users\
Is it possible to do this in Java, because I'm getting a directory using System.getProperty("user.dir"); however that is not the directory I'd want to work at, but rather 1 level down the directory.
是否可以在 中执行此操作Java，因为我使用 System.getProperty("user.dir"); 获取目录；然而，这不是我想要工作的目录，而是目录下一级。
I have thought of using the Path class method; subpath(i,j), but if the "user.dir" were to be changed to another directory, then the returned subpathwould be different.
曾经想过使用Path类的方法；subpath(i,j)，但如果将“user.dir”更改为另一个目录，则返回的subpath将不同。
采纳答案by sethcall
The File class can do this natively.
File 类可以本机执行此操作。
File upOne = new File(System.getProperty("user.dir")).getParentFile()
http://docs.oracle.com/javase/6/docs/api/java/io/File.html#getParentFile%28%29
http://docs.oracle.com/javase/6/docs/api/java/io/File.html#getParentFile%28%29
回答by Java42
On my system, the ".." is a valid component of a path.
Here is an example.
在我的系统上，“..”是路径的有效组成部分。
这是一个例子。
File file;
String userDir = System.getProperty("user.dir");
file = new File(userDir);
System.out.println(file.getCanonicalPath());
file = new File(userDir+"/..");
System.out.println(file.getCanonicalPath());
Output is:
输出是：
C:\anog\workaces\_JAV_1.0.0\CODE_EXAMPLE
C:\anog\workaces\_JAV_1.0.0
回答by ig0774
As the previous answers have pointed out, you can do this using File. Alternatively, using the Java 7 NIO classes, as you appear to be doing, the following should do the same:
正如前面的答案所指出的，您可以使用File. 或者，使用 Java 7 NIO 类，正如您所做的那样，以下应该做同样的事情：
Paths.get(System.getProperty("user.dir") + "/..").toRealPath();
Note that "/" is a valid directory separator on the Windows file system as well (though I tested this code on Linux).
请注意，“/”也是 Windows 文件系统上的有效目录分隔符（尽管我在 Linux 上测试了此代码）。
回答by Sushila Jyothi Lévêque
private static void downDir(int levels) {
String oldPath = System.getProperty("user.dir");
String[] splitedPathArray = oldPath.split("/");
levels = splitedPathArray.length - levels;
List<String> splitedPathList = Arrays.asList(splitedPathArray);
splitedPathList = splitedPathList.subList(0, levels);
String newPath = String.join("/", splitedPathList);
System.setProperty("user.dir", newPath);
}
Should work. For the levels, just specify 1.
应该管用。对于级别，只需指定 1。
