图形验证码功能实现

1、引入依赖：

<!-- google kaptcha 验证码 -->
<dependency>
  <groupId>com.github.axet</groupId>
  <artifactId>kaptcha</artifactId>
  <version>0.0.9</version>
</dependency>

2、配置文件

package cn.laoyao.server.config;

import com.google.code.kaptcha.impl.DefaultKaptcha;
import com.google.code.kaptcha.util.Config;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.util.Properties;

/** 验证码配置类
 * @author bing  @create 2021/1/15-下午7:38
 */
@Configuration
public class CaptchaConfig {

    @Bean
    public DefaultKaptcha defaultKaptcha(){
        // 验证码生成器
        DefaultKaptcha defaultKaptcha = new DefaultKaptcha();
        // 配置
        Properties properties = new Properties();
        // 是否有边框
        properties.setProperty("kaptcha.border","yes");
        // 设置边框颜色
        //properties.setProperty("kaptcha.border.color","105,179,90");
        properties.setProperty("kaptcha.border.color","224,224,224");
        // 边框粗细度，默认为1
        properties.setProperty("kaptcha.border.thickness","1");
        // 设置验证码文本字符颜色，默认黑色
        //properties.setProperty("kaptcha.textproducer.font.color", "blue");
        // 设置字体样式
        properties.setProperty("kaptcha.textproducer.font.names", "微软雅黑");
        //properties.setProperty("kaptcha.textproducer.font.names", "宋体,楷体,微软雅黑");
        // 验证码 session key
        properties.setProperty("kaptcha.session.key", "code");
        // 验证码图片宽度，默认为 200
        properties.setProperty("kaptcha.image.width", "100");
        // 验证码图片高度，默认为40
        properties.setProperty("kaptcha.image.height", "40");
        // 字体大小
        properties.setProperty("kaptcha.textproducer.font.size", "30");
        // 验证码长度
        properties.setProperty("kaptcha.textproducer.char.length", "4");
        // 没有干扰
        properties.setProperty("kaptcha.noise.impl", "com.google.code.kaptcha.impl.NoNoise");// 没有干扰

        Config config = new Config(properties);
        defaultKaptcha.setConfig(config);

        return defaultKaptcha;
    }
}

3、controller接口实现

package cn.laoyao.server.controller;

import com.google.code.kaptcha.impl.DefaultKaptcha;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.image.BufferedImage;
import java.io.IOException;

/**
 * 验证码控制器
 *
 * @author bing  @create 2021/1/15-下午7:54
 */
@RestController
public class CaptchaController {

    @Autowired
    private DefaultKaptcha defaultKaptcha;

    @ApiOperation(value = "验证码")
    @GetMapping(value = "/captcha",produces = "image/jpeg")
    public void captcha(HttpServletRequest request, HttpServletResponse response) {
        // 定义 response 输出类型为 image/jpeg 类型
        response.setDateHeader("Expires", 0);
        response.setHeader("Cache-Control", "no-store,no-cache,must-revalidate");
        response.addHeader("Cache-Control", "post-check=0,pre-check=0");
        response.setHeader("Pragma", "no-cache");
        response.setContentType("image/jpeg");
        // 生成验证码 开始
        String text = defaultKaptcha.createText(); // 获取验证码文本内容
        System.out.println("验证码文本内容：" + text);
        request.getSession().setAttribute("captcah", text);
        BufferedImage image = defaultKaptcha.createImage(text); // 根据文本内容创建图形验证码
        ServletOutputStream outputStream = null;
        try {
            outputStream = response.getOutputStream();
            ImageIO.write(image,"jpg",outputStream); // 输出流输出图片，格式为jpg
            outputStream.flush();
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            if (null!=outputStream) {
                try {
                    outputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        // 生成验证码 结束
        // 查看验证码： http://localhost:8081/captcha

    }
}

4、测试