public void replaceSpace(char[] s, int length) {
		if (s == null || length == 0) {
			return;
		}
		int spaceCount = 0;
		for (int i = 0; i < length; i++) {
			if (s[i] == ' ')
				spaceCount++;
		}
		int j = spaceCount;
		for (int i = length - 1; i >= 0; i--) {
			if (s[i] == ' ') {
				j--;
				s[i + j * 2] = '%';
				s[i + 1 + j * 2] = '2';
				s[i + 2 + j * 2] = '0';
			} else if (j > 0) {
				s[i + j * 2] = s[i];
			} else {
				break;
			}
		}
	}