Java验证码的生成方法有哪些

使用Java自带的Random类生成随机数

import java.util.Random;public String generateCaptcha(int length) {    StringBuilder captcha = new StringBuilder();    Random random = new Random();    for (int i = 0; i < length; i++) {        captcha.append(random.nextInt(10));    }    return captcha.toString();}

使用Apache Commons库生成随机字符串

import org.apache.commons.text.RandomStringGenerator;public String generateCaptcha(int length) {    RandomStringGenerator generator = new RandomStringGenerator.Builder()            .withinRange('0', '9')            .build();    return generator.generate(length);}

使用SecureRandom类生成安全的随机数

import java.security.SecureRandom;import java.util.Base64;public String generateCaptcha(int length) {    SecureRandom random = new SecureRandom();    byte[] bytes = new byte[length];    random.nextBytes(bytes);    return Base64.getEncoder().encodeToString(bytes).substring(0, length);}

使用UUID生成唯一的验证码

import java.util.UUID;public String generateCaptcha() {    String uuid = UUID.randomUUID().toString().replaceAll("-", "");    return uuid.substring(0, 6);}