java 递归调用自动读取某文件夹下所有文件（递归调用）

import java.io.File;  
import java.io.FileNotFoundException;  
import java.io.IOException;  
import java.util.ArrayList;  
  
  
public class readFile {  
    private static ArrayList listname = new ArrayList();  
    public static void main(String[] args)throws Exception{  
        readAllFile("data/");  
        System.out.println(listname.size());  
    }  
    public static void readAllFile(String filepath) {  
        File file= new File(filepath);  
        if(!file.isDirectory()){  
            listname.add(file.getName());  
        }else if(file.isDirectory()){  
            System.out.println("文件");  
            String[] filelist=file.list();  
            for(int i = 0;i