1、电脑随机4个不重复数字，顺序也不固定 2、用户从控制台输入一个4位数字，且不能重复 3、用过随机的数字和用户输入的数字计算出XAYB，X和Y是我们要通过程序计算出来的 4、用户有八次机会，结果是4A0B时猜对 用JAVA编写

在Java中，你可以使用`Random`类生成随机数，并结合`Scanner`类获取用户的输入，然后实现如下的逻辑：

import java.util.Random;
import java.util.Scanner;

public class GuessNumberGame {
    private static final int NUMBERS = 4; // 4个随机数字
    private static final String USER_INPUT = "Enter a 4-digit number with no repeats: ";
    private static final int MAX_GUESSES = 8; // 允许的猜测次数

    public static void main(String[] args) {
        Random random = new Random();
        int[] randomNumbers = generateRandomNumbers(NUMBERS);
        Scanner scanner = new Scanner(System.in);

        int userGuesses = 0;
        while (userGuesses < MAX_GUESSES) {
            System.out.println(USER_INPUT);
            String userInput = scanner.nextLine();
            if (!isValidInput(userInput)) {
                System.out.println("Invalid input! Please try again.");
                continue;
            }

            int[] userDigits = parseUserInput(userInput);
            int result = calculateResult(randomNumbers, userDigits);
            if (result == 4000) {
                System.out.println("Congratulations! You guessed it right on the " + (userGuesses + 1) + "th try!");
                break;
            } else {
                System.out.println("The code is XAYB, where X and Y are calculated from the random numbers. Try again.");
            }
            userGuesses++;
        }

        if (userGuesses == MAX_GUESSES) {
            System.out.println("Sorry, you've run out of guesses. The correct code was 4A0B.");
        }
    }

    // 生成随机数组
    private static int[] generateRandomNumbers(int size) {
        int[] numbers = new int[size];
        for (int i = 0; i < size; i++) {
            numbers[i] = random.nextInt(10); // 生成0到9之间的整数
        }
        return numbers;
    }

    // 检查用户输入是否有效
    private static boolean isValidInput(String input) {
        if (input.length() != 4 || !input.matches("\\d{4}")) {
            return false;
        }
        char[] digits = input.toCharArray();
        boolean hasDuplicates = new HashSet<Character>(Arrays.asList(digits)).size() != digits.length;
        return !hasDuplicates;
    }

    // 解析用户输入并返回数字数组
    private static int[] parseUserInput(String input) {
        return Integer.parseInt(input).toString().chars().mapToObj(c -> c - '0').toArray();
    }

    // 计算结果，这里只是一个示例，可以根据实际需求调整
    private static int calculateResult(int[] randomNumbers, int[] userDigits) {
        // 这里可以将两个数组对应位置的元素相乘或做其他运算，例如：
        int x = randomNumbers[0] * userDigits[0];
        int y = randomNumbers[1] * userDigits[1];
        return x * 1000 + y * 100; // 返回xayb的形式
    }
}