<dependency>
    <groupId>commons-io</groupId>
    <artifactId>commons-io</artifactId>
    <version>2.4</version>
</dependency>

import org.apache.commons.io.FilenameUtils;

public class IODemo {
    public static void main(String[] args) {
        String filename = "/root/name.txt";

        System.out.println(FilenameUtils.getName(filename));
        // name.txt

        System.out.println(FilenameUtils.getBaseName(filename));
        // name

        System.out.println(FilenameUtils.getExtension(filename));
        // txt

    }
}