• pom依赖

<!-- Kaptcha -->
<dependency>
    <groupId>com.github.penggle</groupId>
    <artifactId>kaptcha</artifactId>
    <version>${kaptcha.version}</version>
</dependency>

• KaptchaConfig

@Bean(name="captchaProducer")
public DefaultKaptcha getKaptchaBean(){
    DefaultKaptcha defaultKaptcha=new DefaultKaptcha();
    Properties properties=new Properties();
    properties.setProperty("kaptcha.border", "yes");
    properties.setProperty("kaptcha.border.color", "204,204,204");
    properties.setProperty("kaptcha.image.width", "125");
    properties.setProperty("kaptcha.image.height", "60");
    properties.setProperty("kaptcha.background.clear.from", "245,245,245");
    properties.setProperty("kaptcha.background.clear.to", "245,245,245");
    properties.setProperty("kaptcha.noise.color", "195,35,97");
    properties.setProperty("kaptcha.textproducer.char.length", "4");
    properties.setProperty("kaptcha.textproducer.font.size", "40");
    properties.setProperty("kaptcha.textproducer.font.color", "195,35,97");
    properties.setProperty("kaptcha.textproducer.font.names", "宋体,楷体,微软雅黑");
    Config config=new Config(properties);
    defaultKaptcha.setConfig(config);
    return defaultKaptcha;
}

• KaptchaService

@Resource
Producer captchaProducer;

@Override
public BufferedImage getImgCode() {
    String codeText = captchaProducer.createText();
    // 利用生成的字符串构建图片
    BufferedImage bi = captchaProducer.createImage(codeText);

    jedisClient.setAndExpire("kaptcha:imgCode:" + codeText, codeText,300);
    return bi;
}

• 方式一 生成图片

@RequestMapping(value = "/getImgCode", method = RequestMethod.GET)
public void getCode(HttpServletResponse response) {
    ResultDto resultDto = new ResultDto();

    BufferedImage codeImage = kaptchaService.getImgCode();
    response.setDateHeader("Expires", 0L);
    response.setHeader("Pragma", "No-cache");
    response.setHeader("Cache-Control", "no-cache");
    response.addHeader("Cache-Control", "no-cache");
    response.setContentType("image/jpeg");
    ServletOutputStream out = null;

    try {
        out = response.getOutputStream();
        ImageIO.write(codeImage, "jpg", out);
        out.flush();
    } catch (IOException var15) {
        logger.error(var15.getMessage(), var15);
    } finally {
        if (out != null) {
            try {
                out.close();
            } catch (IOException var14) {
                logger.error(var14.getMessage(), var14);
            }
        }

    }
}

显示

<img src="***/getImgCode?math="+Math.random() onClick="this.src='***/getImgCode?math='+Math.random()"/>

• 方式二 生成base64

@RequestMapping(value = "/getImgCode", method = RequestMethod.GET)
public ResultDto getCode(HttpServletResponse response) {
    ResultDto resultDto = new ResultDto();

    BufferedImage codeImage = kaptchaService.getImgCode();
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    try {
        ImageIO.write(codeImage, "jpg", baos);
        baos.flush();
    } catch (IOException var15) {
        logger.error(var15.getMessage(), var15);
    } finally {
        if (baos != null) {
            try {
                baos.close();
            } catch (IOException var14) {
                logger.error(var14.getMessage(), var14);
            }
        }

    }
    byte[] bytes = baos.toByteArray();
    String result = encoder.encodeBuffer(bytes).trim();
    resultDto.setData(result);
    return resultDto;
}

显示

<img src="data:image/png;base64,***" onClick="this.src="data:image/png;base64,***"/>

解决Docker部署无字体空指针

• 构建docker镜像

FROM  docker.private/openjdk:fonts

MAINTAINER Qihang

VOLUME /tmp

COPY merchant-rest/target/merchant.jar merchant.jar

ENV JAVA_OPTS="-Duser.timezone=Asia/Shanghai"

ENTRYPOINT [ "sh", "-c", "java $JAVA_OPTS -Djava.security.egd=file:/dev/./urandom -jar /merchant.jar" ]

• 部署获取图片验证码，报找不到字体空指针

• 解决方案Dockerfile

FROM openjdk:8-jdk-alpine

MAINTAINER Qihang <leiyang@ranbb.com>

RUN set -xe \
&& apk --no-cache add ttf-dejavu fontconfig

• build

docker build -t docker.private/openjdk:fonts .

• 简单描述
  • 报字体空指针，说明openjdk:8-jdk-alpine没有字体。
  • 解决方法就是加入字体Dockerfile
  • 找不到字体解决了，同时出现了构建镜像慢的问题
  • 解决方案，把安装字体的命令单独提取一层为基础镜像
  • 把构建服务的Docker引用那个基础镜像