public class  Sub
{
	/**
	 * ====按字节长度截取字符串======  
	 * 注意：长度是以byte为单位的，一个汉字是2个byte
	 * @param str :要截取的字符串
	 * @param toCount 截取数目
	 * @param more 截取后追加内容
	 * @return 截取结果
	 */
	public String substring(String str, int toCount, String more) {
		int reInt = 0;
		String reStr = "";
		if (str == null)
			return "";
		char[] tempChar = str.toCharArray();
		for (int kk = 0; (kk < tempChar.length && toCount > reInt); kk++) {
			String s1 = str.valueOf(tempChar[kk]);
			byte[] b = s1.getBytes();
			reInt += b.length;
			reStr += tempChar[kk];
		}
		if (toCount == reInt || (toCount == reInt - 1))
			reStr += more;
		return reStr;
	}
}