截取字符串转换首字母为大写

@Test
    void contextLoads() {
        String str ="!dasd_asda_dasjdlkaj";
        System.out.println(a(str));
    }
    //截取字符串 转换大写并且输出
    String a(String name) {
        String[] str= {};
        StringBuilder sb = new StringBuilder();
        str = name.split("_");
        for (int i=0; i<str.length;i++ ){
            str[i] = text(str[i]);
        }
        for (int j = 0;j<str.length;j++){
            if(j==str.length-1){
                sb.append(str[j]);
                return sb.toString();
            }
            sb.append(str[j]).append("_");
        }

            return sb.toString();
    }
    //转化大小写
    String  text(String name){
        char[] ca = name.toCharArray();
        //ascii 码范围
        if (ca[0]>=65&&ca[0]<=90 || ca[0]<90||ca[0]>122){
            return String.valueOf(ca);
        }
        ca[0]-=32;
        return String.valueOf(ca);
    }