Date: 2014oct19
Update: 2025sep8
Language: java
Level: novice
Q. Java: Change all whitespace into underscores in a String
A. Here is a nice way to clean a string:
String clean(final String s) {
return s.trim().replaceAll("\\s+", "_");
}
trim() removes leading and trailing whitespace (tab, space, newline) characters.
Then the replaceAll("\\s+","_") converts any run of whitespace into a underscore.
This is something you might want to do to make a file name.
Full working example:
class Demo {
static String clean(final String s) {
return s.trim().replaceAll("\\s+", "_");
}
public static void main(String [] args) {
String cleanFilename = clean(" This is a filename.jpg ");
System.out.println("clean=" + cleanFilename);
}
}
Output:
clean=This_is_a_filename.jpg