public static String parseName(String str) {
    // String str = "app_login;change_pwd;get_user_by_code";
    // 正则表达式规则
    String regEx = "[_]{1}[A-Za-z]{1}";
    // 编译正则表达式
    Pattern pattern = Pattern.compile(regEx);
    // 忽略大小写的写法
    // Pattern pat = Pattern.compile(regEx, Pattern.CASE_INSENSITIVE);
    Matcher matcher = pattern.matcher(str);
    while (matcher.find()) {
        System.out.println(matcher.group());
        /*
        _l
        _p
        _u
        _b
        _c
        */
    }
    return "";
}