利用java怎么对文件目录进行读写删除

public String getInputMessage() throws IOException...{         System.out.println("请输入您的命令∶");         byte buffer[]=new byte[1024];         int count=System.in.read(buffer);         char[] ch=new char[count-2];//最后两位为结束符，删去不要         for(int i=0;i<count-2;i++)             ch[i]=(char)buffer[i];         String str=new String(ch);         return str;     }