Split directory path with another path

user_1268668 0
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I read the directory path using system properties in java which will work both in windows and Linux based systems. Now I need to split this path with only a portion of the path to retrieve the rest. eg., C:\Test1\Test2\Test3\Test4

I need to split the above path with C:\Test1\Test2 and retrieve Test3\Test4. When I get this as string and use split function that will give me error as illegal character because of "\" character. If I plan to escape this character with "\\", this may not work in Linux box. Is there a way I can make this work both in Linux and Windows?

java-8 java
4 Answers

You are looking for File.separator. Use it to split your string.

From the docs,

The system-dependent default name-separator character, represented as a string for convenience.

user_61403140

Use the below approach.

 //Windows
   String s = "C:\\Test1\\Test2\\Test3\\Test4";
   String[] output = s.split(("/".equals(File.separator))? File.separator : "\\\\" );
   //output: [C:, Test1, Test2, Test3, Test4]

 //Linux:
   String linuxString = "/Test1/Test2/Test3/Test4";
   String[] linuxOutput = linuxString.split(("/".equals(File.separator))? File.separator : "\\\\" );
   //output: [, Test1, Test2, Test3, Test4]

Hope this will solve the issue.

user_41489020

The pattern passed to String.split has the regular expression syntax, thus the java.util.regex package is the place to look for additional tools for dealing with them, like quoting a string to enforce literal matching.

So a solution only using system properties and string operations would look like

String path=System.getProperty("your.property"), sep=System.getProperty("file.separator");
for(String s: path.split(Pattern.quote(sep)))
    System.out.println(s);

However, there is no reason not to use the dedicated APIs:

Path path = Paths.get(System.getProperty("your.property"));
if(path.isAbsolute()) System.out.println(path.getRoot());
for(Path p: path)
    System.out.println(p);

Note that this also handles root paths correctly, i.e. on Windows, the root of a drive is like C:\, not C:, and on Linux, the root is /, not an empty string, and both cases are not handled correctly when just splitting at the separator chars.

Even before Java 7, there was an API that could handle this:

File path = new File(System.getProperty("your.property"));
for(File f = path; f != null; f = f.getParentFile())
    System.out.println(f.getName().isEmpty()? f.getPath(): f.getName());

though the code will iterate the elements in the opposite order.

Note, how simple your specific task of splitting at two levels above the path becomes with the dedicated API:

Path path = Paths.get(System.getProperty("your.property"));
Path first = path.getParent().getParent(), second = first.relativize(path);

System.out.println("first: "+first);
System.out.println("second: "+second);
user_27114880

You can use separator when you are building a file path.

Use java.io.File.separator

user_71814200
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