下划线分隔的字符串，转换为驼峰式字符串

方法一：

public static void main(String[] args) { String aa="part_vote_num"; Pattern p = Pattern.compile("_[a-z]"); Matcher m = p.matcher(aa); StringBuffer sb = new StringBuffer(); while (m.find()) { String firstChar =  m.group().substring(1,2);     m.appendReplacement(sb, firstChar.toUpperCase()); } m.appendTail(sb); System.out.println(sb.toString());}

方法二：

public static void main(String[] args) {String aa="part_vote_num";StringBuilder sb = new StringBuilder();boolean low = true;for(int i=0; i<aa.length(); i++){if(aa.charAt(i)=='_'){low = false;}else{if(low){sb.append(aa.charAt(i));}else{sb.append(Character.toUpperCase(aa.charAt(i)));low=true;}}}System.out.println(sb.toString());}

方法三：

public static void main(String[] args) {String aa="part_vote_num";StringBuilder sb = new StringBuilder();String[] arr = aa.split("_");sb.append(arr[0]);for(int i=1; i<arr.length; i++){String temp = arr[i].substring(0, 1).toUpperCase()+arr[i].substring(1, arr[i].length());sb.append(temp);}System.out.println(sb.toString());}