java批量修改文件名的实现方法

import java.io.*;  class filesRename {   public static void main(String[] args) throws IOException   {     String str1 = new String("这里是需要删除的文件名前缀");     int sublen = str1.length();          String dir = "f://java1";     File f = new File(dir);     File[] f1 = f.listFiles();          for(File r :f1)     {       String strsub = r.getName();       String newName = strsub.substring(sublen);              File newDir = new File(dir+"//"+newName);  ;              sop("rename::"+newDir+"__________"+r.renameTo(newDir));     }        }   public static void sop(Object obj)   {     System.out.println(obj);   } }