使用 Integer.parseInt(String input, int radix)将任何类型的数字转换为 Integer。

String binaryNumber = "10101";
int decimal1 = Integer.parseInt(binaryNumber, 2);
System.out.println(binaryNumber + " in Base 10 : " + decimal1);
String octalNumber = "456";
int decimal2 = Integer.parseInt(octalNumber, 8);
System.out.println(octalNumber + " in Base 10 : " + decimal2);
String hexNumber = "ABCD";
int decimal3 = Integer.parseInt(hexNumber, 16);
System.out.println(hexNumber + " in Base 10 : " + decimal3);

输出：

10101 in Base 10 : 21
456 in Base 10 : 302
ABCD in Base 10 : 43981