java - 在 FOR 循环中使用大量 IF 语句

Question

有没有更简单的方法来完成这样的任务，我不必使用大量 IF 语句。

for (int i = 0; i < registration.length(); i++) {
        char numberFromReg = registration.charAt(i);
        String yearFromReg = "";
        if (numberFromReg == '1') {
            yearFromReg += "1";
        }   else if (numberFromReg == '2') {
            yearFromReg += "2";
        }   else if (numberFromReg == '3') {
            yearFromReg += "3";
        }   else if (numberFromReg == '4') {
            yearFromReg += "4";
        }   else if (numberFromReg == '5') {
            yearFromReg += "5";
        }   else if (numberFromReg == '6') {
            yearFromReg += "6";
        }   else if (numberFromReg == '7') {
            yearFromReg += "7";
        }   else if (numberFromReg == '8') {
            yearFromReg += "8";
        }   else if (numberFromReg == '9') {
            yearFromReg += "9";
        }   else if (numberFromReg == '0') {
            yearFromReg += "0";
        }
    }

Answer 1

似乎您只需要数字，所以您可以将replaceAll 用作

yearFromReg  = registration.replaceAll("\\D","");

\\D :表示非数字值，因此 replaceAll 将从字符串中删除所有非数字值。