教程

图形验证码属于老生常谈了，具体细节这里就不说了。生成图形验证码的办法非常多，今天讲解一种通过Kaptcha组件快速生成图形验证码的方法。
Kaptcha是谷歌开源的一款简单实用的图形验证码组件。我个人推荐它的最大原因是容易上手，采用约定大于配置的方式，快速契合到项目中。
话不多说，我们看看该如何使用它：

2. <groupId>com.google.code.kaptcha</groupId>

3. <artifactId>kaptcha</artifactId>

2. public class KaptchaConfig {

5. public DefaultKaptcha getDefaultKaptcha(){

6. com.google.code.kaptcha.impl.DefaultKaptcha defaultKaptcha = new com.google.code.kaptcha.impl.DefaultKaptcha();

7. Properties properties = new Properties();

8. properties.put("kaptcha.border", "no");

9. properties.put("kaptcha.textproducer.font.color", "red");

10. properties.put("kaptcha.image.width", "213");

11. properties.put("kaptcha.image.height", "88");

12. properties.put("kaptcha.textproducer.font.size", "45");

13. properties.put("kaptcha.session.key", "verifyCode");

14. properties.put("kaptcha.textproducer.char.space", "6");

15. properties.put("kaptcha.obscurificator.impl", "com.google.code.kaptcha.impl.WaterRipple");

17. properties.put("kaptcha.background.clear.from", "yellow");

18. properties.put("kaptcha.background.clear.to", "green");

19. Config config = new Config(properties);

20. defaultKaptcha.setConfig(config);

1. @GetMapping("/login/getVerifyCode")

2. public void getVerifyCode(String loginKey,

3. HttpServletRequest httpServletRequest,

4. HttpServletResponse httpServletResponse) {

6. log.warn("query verify Code" + loginKey);

7. loadService.getVerifyCode(loginKey, httpServletRequest, httpServletResponse);

9. log.error("get verify Code failed :", e);

1. public void getVerifyCode(String loginKey, HttpServletRequest httpServletRequest,

2. HttpServletResponse httpServletResponse) throws IOException {

3. ByteArrayOutputStream imgOutputStream = new ByteArrayOutputStream();

6. String verifyCode = captchaProducer.createText();

9. captchaMap.put(loginKey, verifyCode);

10. log.warn("reset verify code key {}, code {}", loginKey, verifyCode);

11. BufferedImage challenge = captchaProducer.createImage(verifyCode);

12. ImageIO.write(challenge, "jpg", imgOutputStream);

13. } catch (IllegalArgumentException | IOException e) {

14. httpServletResponse.sendError(HttpServletResponse.SC_NOT_FOUND);

17. byte[] captchaOutputStream = imgOutputStream.toByteArray();

18. httpServletResponse.setHeader("Cache-Control", "no-store");

19. httpServletResponse.setHeader("Pragma", "no-cache");

20. httpServletResponse.setDateHeader("Expires", 0);

21. httpServletResponse.setContentType("image/jpeg");

22. try (ServletOutputStream responseOutputStream = httpServletResponse.getOutputStream()) {

23. responseOutputStream.write(captchaOutputStream);

24. responseOutputStream.flush();

25. } catch (IOException ex) {

26. log.error("find ex in create a new verify Code", ex);