问题描述
直接来自此 Java Oracle教程:
Directly from this Java Oracle tutorial:
有人可以用它做一个真实的例子吗?它们与跨越目录边界"是什么意思?越过目录边界，我想像是要检查从根目录到getNameCount()-1的文件.同样，一个真实的例子可以解释实践中*和**之间的区别.
Could anybody do a real example out of it?What do they mean with "crosses directory boundary"?Crossing the directory boundary, I imagine something like checking the file from root to getNameCount()-1.Again a real example explaining the difference between * and ** in practice would be great.
推荐答案
FileSystem#getPathMatcher() 有一些非常好的示例和说明
The javadoc for FileSystem#getPathMatcher() has some pretty good examples and explanations
*.java Matches a path that represents a file name ending in .java
*.* Matches file names containing a dot
*.{java,class} Matches file names ending with .java or .class
foo.? Matches file names starting with foo. and a single character extension
/home/*/* Matches /home/gus/data on UNIX platforms
/home/** Matches /home/gus and /home/gus/data on UNIX platforms
C:\\* Matches C:\foo and C:\bar on the Windows platform (note that the backslash is escaped; as a string literal in the Java Language the pattern would be "C:\\\\*")
因此/home/**将与/home/gus/data匹配，但/home/*不会.
So /home/** would match /home/gus/data, but /home/* wouldn't.
/home/*表示每个文件直接位于/home目录中.
/home/* is saying every file directly in the /home directory.
/home/**表示/home内部任何目录中的每个文件.
/home/** is saying every file in any directory inside /home.
*与**的示例.假设您当前的工作目录为/Users/username/workspace/myproject，则以下内容仅与./myproject文件(目录)匹配.
Example of * vs **. Assuming your current working directory is /Users/username/workspace/myproject, then the following will only match the ./myproject file (directory).
PathMatcher pathMatcher = FileSystems.getDefault().getPathMatcher("glob:/Users/username/workspace/*");
Files.walk(Paths.get(".")).forEach((path) -> {
path = path.toAbsolutePath().normalize();
System.out.print("Path: " + path + " ");
if (pathMatcher.matches(path)) {
System.out.print("matched");
}
System.out.println();
});
如果使用**，它将匹配该目录中的所有文件夹和文件.
If you use **, it will match all folders and files within that directory.
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