Java实现验证码、数字加密、双色球系统小案例

	
    public static String createCode(int n){
        String code = "";
        for (int i = 0; i < n; i++) {
            Random random = new Random();
            // 生成一个随机字符：英文大写 小写 数字(0、1、2)
            int type = random.nextInt(3);
            switch (type) {
                case 0:
                    //大写字符 (A 65 - Z 65 + 25)
                    code += (char) (random.nextInt(26) + 'A');
                    break;
                case 1:
                    //小写字符
                    code += (char) (random.nextInt(26) + 'a');
                    break;
                case 2:
                    //数字字符
                    code += random.nextInt(10);
                    break;
            }
        }
        return code;
    }

• 实现

import java.util.Scanner;


public class Test03 {
    public static void main(String[] args) {
        // 需求：数字加密
        // 1、定义一个数字存入需要加密的数字
        Scanner cin = new Scanner(System.in);
        System.out.println("请输入需要加密的数字个数：");
        int len = cin.nextInt();
        int[] arr = new int[len];
        for (int i = 0; i < len; i++) {
            System.out.print("请输入第"+(i+1)+"个数字：");
            arr[i] = cin.nextInt();
        }
        // 加密
        encryption(arr);
        // 打印
        printArray(arr);
    }

    
    public static void printArray(int[] arr) {
        System.out.print("[");
        for (int i = 0; i < arr.length; i++) {
            System.out.print(i == arr.length -1 ? arr[i] : arr[i] + ", ");
        }
        System.out.println("]");
    }

    public static void encryption(int[] arr) {
        for (int i = 0; i < arr.length; i++) {
            arr[i] = (arr[i] + 5) % 10;
        }
        // 反转数组
        reverse(arr);
    }

    public static void reverse(int[] arr) {
        for (int i = 0, j = arr.length-1; i < j; i++,j--) {
            int t = arr[i];
            arr[i] = arr[j];
            arr[j] = t;
        }
    }
}

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• 这里既是加密程序也是解密程序

• 业务分析、随机生成一组中奖号码
• 用户输入一组双色球号码
• 判断中奖情况

实现

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


public class Test04 {
    public static void main(String[] args) {
        // 调用方法生成一组幸运号码
        int[] luckNumbers = createLucNumber();
        // 输入用户选取的号码
        int [] userNumbers = userInputNumber();
        // 判断是否中奖
        judge(luckNumbers, userNumbers);
    }

    
    public static void judge(int[] luckNumbers, int[] userNumbers){
        // 命中的红球个数
        int redHitNumbers = 0;
        int blueHitNumbers = 0;

        // 统计命中了红球的个数
        for (int i = 0; i < userNumbers.length-1; i++) {
            for(int j = 0; j < luckNumbers.length-1; j++){
                if (userNumbers[i] == luckNumbers[j]) {
                    redHitNumbers++;
                    break;
                }
            }
        }
        int n = userNumbers.length;
        blueHitNumbers = userNumbers[n-1] == luckNumbers[n-1] ? 1 : 0;

        int money = 0;
        if(blueHitNumbers == 1){
            switch (redHitNumbers) {
                case 0:
                case 1:
                case 2:
                    money = 5;
                    break;
                case 3:
                    money = 10;
                    break;
                case 4:
                    money = 200;
                    break;
                case 5:
                    money = 3000;
                    break;
                case 6:
                    money = 10000000;
                    break;
            }
        } else {
            switch (redHitNumbers) {
                case 4:
                    money = 10;
                    break;
                case 5:
                    money = 200;
                    break;
                case 6:
                    money = 5000000;
                    break;
            }
        }

        System.out.print("开奖号码是：");
        printArray(luckNumbers);
        System.out.print("您的投注号码是：");
        printArray(userNumbers);
        System.out.println("您命中了几个红球："+redHitNumbers);
        System.out.println("您是否命中蓝球："+(blueHitNumbers == 1 ? "是" : "否"));
        if(money == 0){
            System.out.println("感谢您为福利事业做出突出贡献！");
        } else {
            System.out.println("恭喜您，中了"+money+"元");
        }
    }

    public static void printArray(int[] arr) {
        System.out.print("[ ");
        for (int i = 0; i < arr.length; i++) {
            System.out.print(i == arr.length - 1 ? arr[i] : arr[i] + ", ");
        }
        System.out.println("]");
    }
    
    public static int[] userInputNumber(){
        int[] userNumbers = new int[7];
        Scanner cin = new Scanner(System.in);
        for (int i = 0; i < userNumbers.length - 1; i++) {
            System.out.print("请输入第"+(i+1)+"个红球号码(1-33、不重复)：");
            userNumbers[i] = cin.nextInt();
        }
        System.out.print("请输入蓝球号码(1-16、不重复)：");
        userNumbers[userNumbers.length-1] = cin.nextInt();
        return userNumbers;
    }
    
    public static int[] createLucNumber(){
        // 随机六个(1-33)不同的数字，随机一个蓝球号码(1-16)
        int[] numbers = new int[7];
        Random random = new Random();
        for (int i = 0; i < numbers.length-1; i++) {
            while(true){
                int num = random.nextInt(33) + 1;
                if (!check(numbers, i+1, num)) {
                    numbers[i] = num;
                    break;
                }
            }
        }
        // 为第七个位置生成一个蓝球号码
        while(true){
            int num = random.nextInt(16) + 1;
            if (!check(numbers, numbers.length-1, num)) {
                numbers[numbers.length-1] = num;
                break;
            }
        }
        return numbers;
    }

    
    public static boolean check(int[] numbers, int n, int num){
        for(int i = 0; i < n; i++){
            if(numbers[i] == num) {
                return true;
            }
        }
        return false;
    }
}