Java 中的 getPath()、getAbsolutePath() 和 getCanonicalPath() 之间有什么区别? [英] What's the difference between getPath(), getAbsolutePath(), and getCanonicalPath() in Java?

问题描述

Java 中的 getPath()、getAbsolutePath() 和 getCanonicalPath() 有什么区别?

What's the difference between getPath(), getAbsolutePath(), and getCanonicalPath() in Java?

我什么时候使用每一个?

And when do I use each one?

推荐答案

考虑这些文件名:

C: empfile.txt - 这是一个路径、一个绝对路径和一个规范路径.

C: empfile.txt - This is a path, an absolute path, and a canonical path.

.file.txt - 这是一个路径.它既不是绝对路径，也不是规范路径.

.file.txt - This is a path. It's neither an absolute path nor a canonical path.

C: empmyappin..\..file.txt - 这是一个路径和一个绝对路径.这不是规范路径.

C: empmyappin..\..file.txt - This is a path and an absolute path. It's not a canonical path.

规范路径始终是绝对路径.

A canonical path is always an absolute path.

从路径转换为规范路径使其成为绝对路径(通常附加在当前工作目录上，因此例如 ./file.txt 变为 c:/temp/file.txt).文件的规范路径只是净化"路径，删除和解析诸如 .. 之类的内容并解析符号链接(在 unix 上).

Converting from a path to a canonical path makes it absolute (usually tack on the current working directory so e.g. ./file.txt becomes c:/temp/file.txt). The canonical path of a file just "purifies" the path, removing and resolving stuff like .. and resolving symlinks (on unixes).

另请注意以下带有 nio.Paths 的示例:

Also note the following example with nio.Paths:

String canonical_path_string = "C:\Windows\System32\";
String absolute_path_string = "C:\Windows\System32\drivers\..\";

System.out.println(Paths.get(canonical_path_string).getParent());
System.out.println(Paths.get(absolute_path_string).getParent());

虽然两个路径都指向同一个位置，但输出会大不相同:

While both paths refer to the same location, the output will be quite different:

C:Windows
C:WindowsSystem32drivers

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