JAVA字节截取

/**
 * 按字节长度截取字符串
 * 
 * @param str
 *            将要截取的字符串参数
 * @param toCount
 *            截取的字节长度
 * @param more
 *            字符串末尾补上的字符串
 * @return 返回截取后的字符串
 */
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 = String.valueOf(tempChar[kk]);
			byte[] b = s1.getBytes();
			reInt += b.length;
			reStr += tempChar[kk];
		}
		if (toCount == reInt || (toCount == reInt - 1))
			reStr += more;
		return reStr;
	}