下划线转驼峰

private static final Pattern pattern = Pattern.compile("_(\\w)");

public static String underline2camel(String str) {
    if(StringUtils.isBlank(str)){
        return "";
    }
    StringBuffer sb = new StringBuffer();
    Matcher m = pattern.matcher(str.toLowerCase(Locale.ENGLISH));
    while (m.find()){
        m.appendReplacement(sb,m.group(1).toUpperCase());
    }
    m.appendTail(sb);
    return sb.toString();
}