创建一个类来表示文件名和路径

/**

 * This class assumes that the string used to initialize

 * fullPath has a directory path, filename, and extension.

 * The methods won't work if it doesn't.

 */
/**来自 N o w J a v a . c o m - 时代Java**/

class Filename {

    private String fullPath;

    private char pathSeparator, extensionSeparator;


    public Filename(String str, char sep, char ext) {

        fullPath = str;

        pathSeparator = sep;

        extensionSeparator = ext;

    }


    public String extension() {

        int dot = fullPath.lastIndexOf(extensionSeparator);//时 代 J a v a 提 供

        return fullPath.substring(dot + 1);

    }


    // gets filename without extension

    public String filename() {

        int dot = fullPath.lastIndexOf(extensionSeparator);

        int sep = fullPath.lastIndexOf(pathSeparator);

        return fullPath.substring(sep + 1, dot);

    }


    public String path() {

        int sep = fullPath.lastIndexOf(pathSeparator);

        return fullPath.substring(0, sep);

    }

}

public class FilenameDemo {

    public static void main(String[] args) {

        final String FPATH = "/home/user/index.html";

        Filename myHomePage = new Filename(FPATH, '/', '.');

        System.out.println("Extension = " + myHomePage.extension());

        System.out.println("Filename = " + myHomePage.filename());

        System.out.println("Path = " + myHomePage.path());

    }

}