利用JAVA如何实现将汉字转换为ASCII

public static String ChineseToASCII(byte[] rec) { //从字节读取内容   ByteArrayInputStream bais = new ByteArrayInputStream(rec);   DataInputStream dis = new DataInputStream(bais);   String BTS=null;   try {   BTS=new String(rec,"ISO8859-1");//转换编码   bais.close();   dis.close();   } catch (Exception e) {   e.printStackTrace();   }   return BTS; }    public static void main(String[] args) {    String source="一二三四五六七八九十";    System.out.println(source.length());    String target=ChineseToASCII(source.getBytes());    System.out.println(target);    System.out.println(target.length());  }