import java.io.File;import java.io.IOException;public class Main {    public static void main(String[] args) {        Tools.listFiles(new File("."));    }}class Tools {    public static void listFiles(File dir) {        list(dir, 0);    }    private static void list(File file, int depth) {        int i = depth;        if (file.isFile()) {            while (i-- > 0) {                System.out.print("\t");            }            System.out.println(file.getName());            i = depth;        } else if (file.isDirectory()) {            while (i-- > 0) {                System.out.print("\t");            }            try {                System.out.println(file.getCanonicalPath() + "/");            } catch (IOException e) {                e.printStackTrace();            }            for (File f : file.listFiles()) {                list(f, depth + 1);            }        } else {            new Exception("不是文件或文件夹!").printStackTrace();        }    }}