Extracting relative paths from absolute paths

问题

This is a seemingly simple problem but I am having trouble doing it in a clean manner. I have a file path as follows:

/this/is/an/absolute/path/to/the/location/of/my/file

What I need is to extract /of/my/file from the above given path since that is my relative path.

The way I am thinking of doing it is as follows:

String absolutePath = "/this/is/an/absolute/path/to/the/location/of/my/file";
String[] tokenizedPaths = absolutePath.split("/");
int strLength = tokenizedPaths.length;
String myRelativePathStructure = (new StringBuffer()).append(tokenizedPaths[strLength-3]).append("/").append(tokenizedPaths[strLength-2]).append("/").append(tokenizedPaths[strLength-1]).toString();

This will probably serve my immediate needs but can somebody suggest a better way of extracting sub-paths from a provided path in java?

Thanks

回答1:

Use the URI class:

URI base = URI.create("/this/is/an/absolute/path/to/the/location");
URI absolute =URI.create("/this/is/an/absolute/path/to/the/location/of/my/file");
URI relative = base.relativize(absolute);

This will result in of/my/file.

回答2:

With pure string operations and assuming you know the base path and assuming you only want relative paths below the base path and never prepend a "../" series:

String basePath = "/this/is/an/absolute/path/to/the/location/";
String absolutePath = "/this/is/an/absolute/path/to/the/location/of/my/file";
if (absolutePath.startsWith(basePath)) {
    relativePath = absolutePath.substring(basePath.length());
}

There are surely better ways to do this with classes that are aware of path logic, such as File or URI, though. :)

来源：https://stackoverflow.com/questions/9826769/extracting-relative-paths-from-absolute-paths

标签

java

relative-path

filepath

string-parsing

code-cleanup