大写转下划线的算法 驼峰转 下划线

public static String camel4underline(String param){Pattern  p=Pattern.compile("[A-Z]");if(param==null ||param.equals("")){return "";}StringBuilder builder=new StringBuilder(param);Matcher mc=p.matcher(param);int i=0;while(mc.find()){builder.replace(mc.start()+i, mc.end()+i, "_"+mc.group().toLowerCase());i++;}if('_' == builder.charAt(0)){builder.deleteCharAt(0);}return builder.toString();}