利用递归打印目录

import java.io.*;

public class FileList{
    
    void tree(File file , int level){
        String str = "";
        for(int i=0;i<level;i++){
            str += "  ";
        }
        File[] list = file.listFiles();
        for(int i=0;i<list.length;i++){
            System.out.println(str + list[i].getName());
            if(list[i].isDirectory()){
                tree(list[i],level+1);
            }
        }
    }
    
    public static void main(String[] args){
        FileList list = new FileList();
        File f = new File("D:/A");
        System.out.println("A");
        list.tree(f,0);
    }
    
}