java，将26个英文字母，转换为1-26数字;

Question

例如 String str = "abcdef";转换为str = "123456";效率最高算法；

Answer 1

private void getIndex(String str){

byte[] bytes = str.getBytes();

for (int i = 0; i < bytes.length; i++) {

byte b = bytes[i];

System.out.println(b - 96);

}

}

Answer 2

String a = "abcdefghijklmnopqrst";

byte[] b = a.getBytes();

for (int i = 0; i < b.length; i++) {

b[i] = (byte) (b[i] - 49);

}

System.out.println(new String(b));

Answer 3

遍历之后，asc码，做减法操作。有大神给好一点的方案？