Java Random 随机数的用法小结

import java.util.Random;

Random random = new Random();
// 或者指定种子
Random random = new Random(long seed);

Random random = new Random();
int randomInt = random.nextInt(); // 生成任意随机整数
int randomIntBetween0And10 = random.nextInt(10); // 生成0到9之间的随机整数

Random random = new Random();
double randomDouble = random.nextDouble();

Random random = new Random();
boolean randomBoolean = random.nextBoolean();

Random random = new Random();
float randomFloat = random.nextFloat();

Random random = new Random();
long randomLong = random.nextLong();

Random random = new Random();

// 生成 [min, max) 范围内的随机整数
int min = 10;
int max = 20;
int randomInRange = random.nextInt(max - min) + min;

// 生成 [min, max) 范围内的随机 double 值
double minDouble = 1.0;
double maxDouble = 10.0;
double randomDoubleInRange = random.nextDouble() * (maxDouble - minDouble) + minDouble;

import java.util.Random;

public class RandomStringGenerator {
    private static final String CHARACTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";

    public static String generateRandomString(int length) {
        Random random = new Random();
        StringBuilder sb = new StringBuilder(length);

        for (int i = 0; i < length; i++) {
            int index = random.nextInt(CHARACTERS.length());
            sb.append(CHARACTERS.charAt(index));
        }

        return sb.toString();
    }

    public static void main(String[] args) {
        String randomString = generateRandomString(10);
        System.out.println("随机字符串: " + randomString);
    }
}

import java.util.Random;

public class ShuffleExample {
    public static void shuffleArray(int[] array) {
        Random random = new Random();
        for (int i = array.length - 1; i > 0; i--) {
            int j = random.nextInt(i + 1);
            // 交换元素
            int temp = array[i];
            array[i] = array[j];
            array[j] = temp;
        }
    }

    public static void main(String[] args) {
        int[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
        System.out.println("原始数组:");
        for (int num : array) {
            System.out.print(num + " ");
        }

        shuffleArray(array);

        System.out.println("\n洗牌后的数组:");
        for (int num : array) {
            System.out.print(num + " ");
        }
    }
}

double randomValue = Math.random();

// 生成 [min, max) 范围内的随机整数
int min = 10;
int max = 20;
int randomInt = (int) (Math.random() * (max - min)) + min;

// 生成 [min, max) 范围内的随机 double 值
double minDouble = 1.0;
double maxDouble = 10.0;
double randomDouble = Math.random() * (maxDouble - minDouble) + minDouble;