Java批量修改文件后缀名

import java.io.*;public class RenameFilesExt {  public void reName(String path, String from, String to) {    File f = new File(path);    File[] fs = f.listFiles();    for (int i = 0; i < fs.length; ++i) {      File f2 = fs[i];      if (f2.isDirectory()) {        reName(f2.getPath(), from, to);      } else {        String name = f2.getName();        if (name.endsWith(from)) {          f2.renameTo(new File(f2.getParent() + "/" + name.substring(0, name.indexOf(from)) + to));        }      }    }  }  public static void main(String[] args) {    RenameFilesExt rf = new RenameFilesExt();    rf.reName("E:/a4", ".png", ".yol");  }}