使用 Integer.toString(int input, int radix)将 Integer转换为任何类型的基数。

Integer decimal1 = 21;
String binaryNumber = Integer.toString(decimal1, 2);
System.out.println(decimal1 + " in Base 2 : " + binaryNumber);
Integer decimal2 = 302;
String octalNumber = Integer.toString(decimal2, 8);
System.out.println(decimal2 + " in Base 8 : " + octalNumber);
Integer decimal3 = 43981;
String hexNumber = Integer.toString(decimal3, 16);
System.out.println(decimal2 + " in Base 16 : " + hexNumber);

输出：

21 in Base 2 : 10101
302 in Base 8 : 456
43981 in Base 16 : abcd

方法2：使用Integer.toXXXString(int)

Integer decimal1 = 21;
System.out.println(decimal1 + " in Base 2 : " + Integer.toBinaryString(decimal1));
Integer decimal2 = 302;
System.out.println(decimal2 + " in Base 8 : " + Integer.toOctalString(decimal2));
Integer decimal3 = 43981;
System.out.println(decimal3 + " in Base 16 : " + Integer.toHexString(decimal3));

输出：

21 in Base 2 : 10101
302 in Base 8 : 456
43981 in Base 16 : abcd