java获取字符串的字节长度

public static int getLength(String s) {
    int length = 0;
    for (int i = 0; i < s.length(); i++) {
        int ascii = Character.codePointAt(s, i);
        if (ascii >= 0 && ascii <= 255) {
            length++;
        } else {
            length += 2;
        }
    }
    return length;
}