maven依赖

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
        <relativePath />
    </parent>
    <properties>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
        <springboot.version>2.1.3.RELEASE</springboot.version>
    </properties>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-freemarker</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>com.github.bingoohuang</groupId>
            <artifactId>patchca</artifactId>
            <version>0.0.1</version>
        </dependency>

工具类

/** * 验证码工具类 * * @author zhengzc * @date 2019-08-01 */
public class CaptchaUtil { 
    public static ConfigurableCaptchaService getConfigurableCaptchaService() { 
        ConfigurableCaptchaService cs = new ConfigurableCaptchaService();
        RandomWordFactory wf = new RandomWordFactory();
        wf.setCharacters("23456789abcdefghijkmnpqrstuvwxyzABCDEFGHIJKMNPQRSTUVWXYZ");
        wf.setMaxLength(4);
        wf.setMinLength(4);
        cs.setWordFactory(wf);
        return cs;
    }
    /** * 选择验证码生成工厂 * * @param cs * @param index */
    public static void setFactory(ConfigurableCaptchaService cs, int index) { 
        System.err.println("工厂序号：" + index);
        if (index == 0) { 
            // 弧线波纹
            cs.setFilterFactory(new CurvesRippleFilterFactory(cs.getColorFactory()));
        } else if (index == 1) { 
            // 大理石波纹
            cs.setFilterFactory(new MarbleRippleFilterFactory());
        } else if (index == 2) { 
            // 大理石波纹
            cs.setFilterFactory(new DoubleRippleFilterFactory());
        } else if (index == 3) { 
            // 摇摆波纹
            cs.setFilterFactory(new WobbleRippleFilterFactory());
        } else if (index == 4) { 
            // 扩散的波纹
            cs.setFilterFactory(new DiffuseRippleFilterFactory());
        }
    }
    /** * 选择验证码生成工厂 * * @param cs * @param index */
    public static void setColorFactory(ConfigurableCaptchaService cs, int index) { 
        System.err.println("颜色序号：" + index);
        if (index == 0) { 
            // 自定义颜色
            cs.setColorFactory(getColorFactory());
        } else if (index == 1) { 
            // 梯度变化颜色
            cs.setColorFactory(new GradientColorFactory());
        } else if (index == 2) { 
            // 随机颜色
            cs.setColorFactory(new RandomColorFactory());
        } else if (index == 3) { 
            // 单一颜色
            cs.setColorFactory(new SingleColorFactory());
        }
    }
    /** * 自定义颜色工厂 * * @return */
    private static ColorFactory getColorFactory() { 
        return new ColorFactory() { 
            @Override
            public Color getColor(int x) { 
                Random random = new Random();
                int[] c = { 25, 60, 170};
                int i = random.nextInt(c.length);
                for (int fi = 0; fi < c.length; fi++) { 
                    if (fi == i) { 
                        c[fi] = random.nextInt(71);
                    } else { 
                        c[fi] = random.nextInt(256);
                    }
                }
                return new Color(c[0], c[1], c[2]);
            }
        };
    }
}
/** * 使用谷歌提供的验证码组件patchca来生成验证码 * * @author zhengzc * @date 2019-08-01 */
@Controller
@RequestMapping("/patchca")
public class CaptchaController { 
    @RequestMapping(value = "/getpatchcaImage")
    public void getpatchcaImage(HttpServletRequest request, HttpServletResponse response) throws Exception { 
        ConfigurableCaptchaService cs = CaptchaUtil.getConfigurableCaptchaService();
        CaptchaUtil.setFactory(cs, new Random().nextInt(5));
        CaptchaUtil.setColorFactory(cs, new Random().nextInt(4));
        HttpSession session = request.getSession(false);
        if (session == null) { 
            session = request.getSession();
        }
        setResponseHeaders(response);
        String token = EncoderHelper.getChallangeAndWriteImage(cs, "png", response.getOutputStream());
        session.setAttribute("captchaToken", token);
        System.out.println("当前的 sessionId:" + session.getId() + ",验证码：" + token);
    }
    protected void setResponseHeaders(HttpServletResponse response) { 
        response.setContentType("image/jpeg");
        response.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");
        response.setHeader("Pragma", "no-cache");
        long time = System.currentTimeMillis();
        response.setDateHeader("Last-Modified", time);
        response.setDateHeader("Date", time);
        response.setDateHeader("Expires", time);
    }
}