java字符串根据正则表达式让单词首字母大写

public class Da {
    public static void main(String[] args) {
        String s = "hello_*java_*world";
        System.out.println("转化前："+s);
        String[] strs = s.split("_\*");
        String ret = "";
        for(int i = 0; i < strs.length; i++){
            if (i == (strs.length-1)){
                ret = ret + strs[i].substring(0, 1).toUpperCase() + strs[i].substring(1, strs[i].length());
            }else{
                ret = ret + strs[i].substring(0, 1).toUpperCase() + strs[i].substring(1, strs[i].length())+ "_*";
            }
        }
        System.out.println("转化后："+ret);
    }
}