Java 实战系列·Kaptcha 与数学公式验证码
Kaptcha 与数学公式验证码
kaptcha 实现验证码
Google 的 kaptcha 框架是一个高度可配置的实用验证码生成工具，官方地址：kaptcha github。
Spring 中引入非常简单，首先添加依赖：
<dependency>
<groupId>com.github.penggle</groupId>
<artifactId>kaptcha</artifactId>
<version>2.3.2</version>
</dependency>配置文件：
@Configuration
public class KaptchaConfig {
@Bean
public DefaultKaptcha getDefaultKaptcha() {
DefaultKaptcha defaultKaptcha = new DefaultKaptcha();
Properties properties = new Properties();
// 图片边框
properties.put("kaptcha.border", "yes");
// 字体颜色
properties.put("kaptcha.textproducer.font.color", "black");
// 图片宽
properties.put("kaptcha.image.width", "120");
// 图片高
properties.put("kaptcha.image.height", "40");
// 字体大小
properties.put("kaptcha.textproducer.font.size", "25");
// 验证码长度
properties.put("kaptcha.textproducer.char.space", "4");
// 字体
properties.setProperty("kaptcha.textproducer.font.names", "宋体,楷体,微软雅黑");
Config config = new Config(properties);
defaultKaptcha.setConfig(config);
return defaultKaptcha;
}
}食用：
@Controller
@RequiredArgsConstructor(onConstructor = @__(@Autowired))
public class KaptchaController {
private final DefaultKaptcha captchaProducer;
@GetMapping("/code")
public void defaultKaptcha(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
byte[] captchaOutputStream = null;
ByteArrayOutputStream imgOutputStream = new ByteArrayOutputStream();
try {
//生产验证码字符串并保存到session中
String verifyCode = captchaProducer.createText();
httpServletRequest.getSession().setAttribute("verifyCode", verifyCode);
BufferedImage challenge = captchaProducer.createImage(verifyCode);
ImageIO.write(challenge, "jpg", imgOutputStream);
} catch (IllegalArgumentException e) {
httpServletResponse.sendError(HttpServletResponse.SC_NOT_FOUND);
return;
}
captchaOutputStream = imgOutputStream.toByteArray();
httpServletResponse.setHeader("Cache-Control", "no-store");
httpServletResponse.setHeader("Pragma", "no-cache");
httpServletResponse.setDateHeader("Expires", 0);
httpServletResponse.setContentType("image/jpeg");
ServletOutputStream responseOutputStream = httpServletResponse.getOutputStream();
responseOutputStream.write(captchaOutputStream);
responseOutputStream.flush();
responseOutputStream.close();
}
@GetMapping("/verify")
@ResponseBody
public String verify(@RequestParam("code") String code, HttpSession session) {
if (StringUtils.isEmpty(code)) {
return "验证码不能为空";
}
String kaptchaCode = session.getAttribute("verifyCode") + "";
if (StringUtils.isEmpty(kaptchaCode) || !code.equals(kaptchaCode)) {
return "验证码错误";
}
return "验证成功";
}
}数学公式验证码
引入 redis 依赖并添加工具类：
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>RedisUtil 工具类：
@SuppressWarnings("unchecked")
@Component
@RequiredArgsConstructor(onConstructor = @__(@Autowired))
public class RedisUtil {
private final RedisTemplate redisTemplate;
//=============================common============================
/**
* 指定缓存失效时间
* @param key 键
* @param time 时间(秒)
* @return boolean
*/
public boolean expire(String key, long time) {
try {
if(time > 0) {
redisTemplate.expire(key, time, TimeUnit.SECONDS);
}
return true;
} catch (Exception e) {
e.printStackTrace();
return false;
}
}
/**
* 根据key获取过期时间
* @param key 键 不能为null
* @return 时间(秒) 返回0代表为永久有效
*/
public long getExpire(String key) {
return redisTemplate.getExpire(key, TimeUnit.SECONDS);
}
/**
* 判断key是否存在
* @param key 键
* @return true存在 false不存在
*/
public boolean hasKey(String key) {
try {
return redisTemplate.hasKey(key);
} catch (Exception e) {
e.printStackTrace();
return false;
}
}
/**
* 删除缓存
* @param key 可以传一个值 或多个
*/
public void del(String ...key){
if(key != null && key.length > 0){
if (key.length == 1) {
redisTemplate.delete(key[0]);
} else {
redisTemplate.delete(CollectionUtils.arrayToList(key));
}
}
}
//============================String=============================
/**
* 普通缓存获取
* @param key 键
* @return 值
*/
public Object get(String key) {
return key == null ? null : redisTemplate.opsForValue().get(key);
}
/**
* 普通缓存放入
* @param key 键
* @param value 值
* @return true成功 false失败
*/
public boolean set(String key, Object value) {
try {
redisTemplate.opsForValue().set(key, value);
return true;
} catch (Exception e) {
e.printStackTrace();
return false;
}
}
/**
* 普通缓存放入并设置时间
* @param key 键
* @param value 值
* @param time 时间(秒) time要大于0 如果time小于等于0 将设置无限期
* @return true成功 false 失败
*/
public boolean set(String key, Object value, long time) {
try {
if(time > 0) {
redisTemplate.opsForValue().set(key, value, time, TimeUnit.SECONDS);
} else {
set(key, value);
}
return true;
} catch (Exception e) {
e.printStackTrace();
return false;
}
}
}验证码生成服务 GenerateVerifyCodeService：
@Service
@RequiredArgsConstructor(onConstructor = @__(@Autowired))
public class GenerateVerifyCodeService {
private final RedisUtil redisUtil;
private String LOGIN_CODE = "LOGIN_CODE_%s";
/**
* 创建验证码
*
* @param username 用户
*/
public BufferedImage createVerifyCode(String username) {
int width = 80;
int height = 32;
// 创建图片
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
// 图片背景颜色
g.setColor(new Color(0xDCDCDC));
g.fillRect(0, 0, width, height);
// 绘制边框
g.setColor(Color.black);
g.drawRect(0, 0, width - 1, height - 1);
// 随机
Random rdm = new Random();
// 随便画一些线
for (int i = 0; i < 50; i++) {
int x = rdm.nextInt(width);
int y = rdm.nextInt(height);
g.drawOval(x, y, 0, 0);
}
// 生成验证码
String verifyCode = generateVerifyCode(rdm);
g.setColor(new Color(0, 100, 0));
g.setFont(new Font("Candara", Font.BOLD, 18));
g.drawString(verifyCode.replace("*", "x"), 8, 24);
g.dispose();
// 把验证码存到redis中
int rnd = calc(verifyCode);
// 记录数学公司的结果
redisUtil.set(String.format(LOGIN_CODE, username), String.valueOf(rnd), 60);
//输出图片
return image;
}
/**
* 验证验证码是否正确
*
* @param username 账号
* @param verifyCode 验证码
*/
public boolean checkVerifyCode(String username, int verifyCode) {
if (username == null) {
return false;
}
String redisKey = String.format(LOGIN_CODE, username);
String codeOld = (String) redisUtil.get(redisKey);
if (codeOld == null || Integer.parseInt(codeOld) - verifyCode != 0) {
return false;
}
redisUtil.del(redisKey);
return true;
}
/**
* 传入数学公式，得到结果
*
* @param exp 比如 1+2+3
* @return 6
*/
private static int calc(String exp) {
try {
ScriptEngineManager manager = new ScriptEngineManager();
ScriptEngine engine = manager.getEngineByName("JavaScript");
return (Integer) engine.eval(exp);
} catch (Exception e) {
e.printStackTrace();
return 0;
}
}
private static char[] ops = new char[]{'+', '-', '*'};
/**
* 随机验证码
* + - *
*/
private String generateVerifyCode(Random rdm) {
int num1 = rdm.nextInt(10);
int num2 = rdm.nextInt(10);
int num3 = rdm.nextInt(10);
char op1 = ops[rdm.nextInt(3)];
char op2 = ops[rdm.nextInt(3)];
return "" + num1 + op1 + num2 + op2 + num3;
}
}食用：
@Controller
@RequiredArgsConstructor(onConstructor = @__(@Autowired))
public class KaptchaController {
private final GenerateVerifyCodeService verifyCodeService;
/**
* 获取验证码
*/
@GetMapping("/verifyCode")
@ResponseBody
public String verifyCode(
HttpServletResponse response,
@RequestParam(value = "username", required = true) String username
) {
try {
BufferedImage image = this.verifyCodeService.createVerifyCode(username);
OutputStream out = response.getOutputStream();
ImageIO.write(image, "JPEG", out);
out.flush();
out.close();
return null;
} catch (Exception e) {
e.printStackTrace();
return "验证码生成失败";
}
}
/**
* 登录验证
*/
@PostMapping("/login")
@ResponseBody
public String login(
@RequestParam(value = "username", required = true) String username,
@RequestParam(value = "password", required = true) String password,
@RequestParam(value = "code", required = true) Integer code
) {
if (StringUtils.isEmpty(code)) {
return "验证码不能为空";
}
boolean checkVerifyCode = this.verifyCodeService.checkVerifyCode(username, code);
if (!checkVerifyCode) {
return "验证码错误";
}
return "验证成功";
}
}本文参与 腾讯云自媒体同步曝光计划，分享自作者个人站点/博客。
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