import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Scanner;

public class Test {
    public static void main(String[] args) throws IOException{
        File a=getFile();
        BufferedInputStream bis=new BufferedInputStream(new FileInputStream(a));
        BufferedOutputStream bos=new BufferedOutputStream(new FileOutputStream(getFile().getName()));
        
        int b;
        while((b = bis.read()) != -1) {
            bos.write(b);
        }
        
        bis.close();
        bos.close();

    }
    public static File getFile() {
        System.out.print("请输入路径:");
        Scanner sc=new Scanner(System.in);
        
        while(true) {
            String line=sc.nextLine();
            
            File file=new File(line);
            
            if(! file.exists()) {  //判断文件存不存在
                System.out.println("不是文件重新输入");
            }else if(file.isDirectory()) {  //判断是否是文件夹
                System.out.println("这是一个文件夹");
            }else {
                return file;
            }
        }
    }
}

• Lua中判断是否是文件夹或文件

  import java.io.File;
  File(路径).exists();