Java Integer Reversal: Complete Guide

Integer reversal can be achieved through the following methods:

public class Main {
    public static void main(String[] args) {
        System.out.println(reverseInteger(123)); // 输出：321
        System.out.println(reverseInteger(-123)); // 输出：-321
    }

    public static int reverseInteger(int num) {
        int reversedNum = 0;

        while (num != 0) {
            int digit = num % 10;
            reversedNum = reversedNum * 10 + digit;
            num /= 10;
        }

        return reversedNum;
    }
}

This method takes an integer as input, then uses a loop to extract and reverse each digit of the integer, and finally returns the reversed integer.