SpringBoot之配置google kaptcha

项目中引入POM：

<dependency>
    <groupId>com.google.code.kaptcha</groupId>
    <artifactId>kaptcha</artifactId>
    <version>2.3</version>
</dependency>

该jar在http://mvnrepository.com/artifact/com.google.code.kaptcha/kaptcha 和 https://repository.sonatype.org/#nexus-search;quick~com.google.code.kaptcha 可以下载到。

kaptcha提供了KaptchaServlet来处理验证码的生成并放入session，但这方式在如今的分布式、前后端分离、集群的部署条件显然不适用。

kaptcha生成验证的核心接口类有：

1、com.google.code.kaptcha.Producer，该接口目前只有一个默认实现类：com.google.code.kaptcha.impl.DefaultKaptcha

2、com.google.code.kaptcha.text.TextProducer，该忌口目前只有一个默认实现类：com.google.code.kaptcha.text.impl.DefaultTextCreator

其中Producer是用来处理生成图片的，TextProducer是用来处理生成验证码问题的。

当然我们也可以去实现这个接口来实现自己的自定义的实现。

控制验证码的图片的生成的规则的配置信息都放到了com.google.code.kaptcha.util.Config类中，其源码如下：

 package com.google.code.kaptcha.util;

 import java.awt.Color;
 import java.awt.Font;
 import java.util.Properties;

 import com.google.code.kaptcha.BackgroundProducer;
 import com.google.code.kaptcha.GimpyEngine;
 import com.google.code.kaptcha.NoiseProducer;
 import com.google.code.kaptcha.Producer;
 import com.google.code.kaptcha.impl.DefaultBackground;
 import com.google.code.kaptcha.impl.DefaultKaptcha;
 import com.google.code.kaptcha.impl.DefaultNoise;
 import com.google.code.kaptcha.impl.WaterRipple;
 import com.google.code.kaptcha.text.TextProducer;
 import com.google.code.kaptcha.text.WordRenderer;
 import com.google.code.kaptcha.text.impl.DefaultTextCreator;
 import com.google.code.kaptcha.text.impl.DefaultWordRenderer;
 import com.google.code.kaptcha.util.ConfigHelper;

 public class Config
 {
   private Properties properties;
   private ConfigHelper helper;

   public Config(Properties properties)
   {
     this.properties = properties;
     this.helper = new ConfigHelper();
   }

   /**
    * 设置图片是否有边框
    * @return
    */
   public boolean isBorderDrawn()
   {
     String paramName = "kaptcha.border";
     String paramValue = this.properties.getProperty(paramName);
     return this.helper.getBoolean(paramName, paramValue, true);
   }

   /**
    * 边框颜色   合法值： r,g,b (and optional alpha) 或者 white,black,blue.
    * @return
    */
   public Color getBorderColor()
   {
     String paramName = "kaptcha.border.color";
     String paramValue = this.properties.getProperty(paramName);
     return this.helper.getColor(paramName, paramValue, Color.BLACK);
   }

   /**
    * 边框厚度  合法值：>0
    * @return
    */
   public int getBorderThickness()
   {
     String paramName = "kaptcha.border.thickness";
     String paramValue = this.properties.getProperty(paramName);
     return this.helper.getPositiveInt(paramName, paramValue, 1);
   }

   /**
    * 文本集合，验证码值从此集合中获取
    * @return
    */
   public char[] getTextProducerCharString()
   {
     String paramName = "kaptcha.textproducer.char.string";
     String paramValue = this.properties.getProperty(paramName);
     return this.helper.getChars(paramName, paramValue, "abcde2345678gfynmnpwx".toCharArray());
   }

   /**
    * 验证码长度
    * @return
    */
   public int getTextProducerCharLength()
   {
     String paramName = "kaptcha.textproducer.char.length";
     String paramValue = this.properties.getProperty(paramName);
     return this.helper.getPositiveInt(paramName, paramValue, 5);
   }

   /**
    * 字体类型
    * @param fontSize 见Font中的定义
    * @return
    */
   public Font[] getTextProducerFonts(int fontSize)
   {
     String paramName = "kaptcha.textproducer.font.names";
     String paramValue = this.properties.getProperty(paramName);
     return this.helper.getFonts(paramName, paramValue, fontSize, new Font[] { new Font("Arial", 1, fontSize), new Font("Courier", 1, fontSize) });
   }

   /**
    * 字体大小
    * @return
    */
   public int getTextProducerFontSize()
   {
     String paramName = "kaptcha.textproducer.font.size";
     String paramValue = this.properties.getProperty(paramName);
     return this.helper.getPositiveInt(paramName, paramValue, 40);
   }

   /**
    * 字体颜色  rgb颜色或者Color中的值
    * @return
    */
   public Color getTextProducerFontColor()
   {
     String paramName = "kaptcha.textproducer.font.color";
     String paramValue = this.properties.getProperty(paramName);
     return this.helper.getColor(paramName, paramValue, Color.BLACK);
   }

   /**
    * 干扰线的颜色
    * @return
    */
   public Color getNoiseColor()
   {
     String paramName = "kaptcha.noise.color";
     String paramValue = this.properties.getProperty(paramName);
     return this.helper.getColor(paramName, paramValue, Color.BLACK);
   }

   /**
    * 背景颜色渐变色开始色  rgb或者Color中定义的
    * @return
    */
   public Color getBackgroundColorFrom()
   {
     String paramName = "kaptcha.background.clear.from";
     String paramValue = this.properties.getProperty(paramName);
     return this.helper.getColor(paramName, paramValue, Color.LIGHT_GRAY);
   }

   /**
    * 背景颜色渐变色结束色   rgb或者Color中定义的
    * @return
    */
   public Color getBackgroundColorTo()
   {
     String paramName = "kaptcha.background.clear.to";
     String paramValue = this.properties.getProperty(paramName);
     return this.helper.getColor(paramName, paramValue, Color.WHITE);
   }

   /**
    * 图片的宽度
    * @return
    */
   public int getWidth()
   {
     String paramName = "kaptcha.image.width";
     String paramValue = this.properties.getProperty(paramName);
     return this.helper.getPositiveInt(paramName, paramValue, 200);
   }

   /**
    * 图片的高度
    * @return
    */
   public int getHeight()
   {
     String paramName = "kaptcha.image.height";
     String paramValue = this.properties.getProperty(paramName);
     return this.helper.getPositiveInt(paramName, paramValue, 50);
   }

   /**
    * 图片的session key
    * @return
    */
   public String getSessionKey()
   {
     return this.properties.getProperty("kaptcha.session.key", "KAPTCHA_SESSION_KEY");
   }

   public Properties getProperties()
   {
     return this.properties;
   }

   /**
    * 生成默认的图片生产者实现
    * @return
    */
   public Producer getProducerImpl()
   {
     String paramName = "kaptcha.producer.impl";
     String paramValue = this.properties.getProperty(paramName);
     Producer producer = (Producer)this.helper.getClassInstance(paramName, paramValue, new DefaultKaptcha(), this);
     return producer;
   }

   /**
    * 生成默认的验证码文字生产者实现
    * @return
    */
   public TextProducer getTextProducerImpl()
   {
     String paramName = "kaptcha.textproducer.impl";
     String paramValue = this.properties.getProperty(paramName);
     TextProducer textProducer = (TextProducer)this.helper.getClassInstance(paramName, paramValue, new DefaultTextCreator(), this);

     return textProducer;
   }

   /**
    * 文字干扰实现类，默认DefaultNoise，还可以选择com.google.code.kaptcha.impl.NoNoise没有干扰线的实现类
    * @return
    */
   public NoiseProducer getNoiseImpl()
   {
       String paramName = "kaptcha.noise.impl";
       String paramValue = this.properties.getProperty(paramName);
       NoiseProducer noiseProducer = (NoiseProducer)this.helper.getClassInstance(paramName, paramValue, new DefaultNoise(), this);

       return noiseProducer;
   }

   /**
    * 图片样式的实现类，默认WaterRipple（水纹），还有下面2种可选
    * 鱼眼com.google.code.kaptcha.impl.FishEyeGimpy    阴影com.google.code.kaptcha.impl.ShadowGimpy
    *
    * @return
    */
   public GimpyEngine getObscurificatorImpl()
   {
     String paramName = "kaptcha.obscurificator.impl";
     String paramValue = this.properties.getProperty(paramName);
     GimpyEngine gimpyEngine = (GimpyEngine)this.helper.getClassInstance(paramName, paramValue, new WaterRipple(), this);
     return gimpyEngine;
   }

   /**
    * 文字渲染实现类，默认DefaultWordRenderer，也只有这一个默认的实现类
    * @return
    */
   public WordRenderer getWordRendererImpl()
   {
     String paramName = "kaptcha.word.impl";
     String paramValue = this.properties.getProperty(paramName);
     WordRenderer wordRenderer = (WordRenderer)this.helper.getClassInstance(paramName, paramValue, new DefaultWordRenderer(), this);

     return wordRenderer;
   }

   /**
    * 背景图片实现类，默认DefaultBackground，也只有这一个默认实现类
    * @return
    */
   public BackgroundProducer getBackgroundImpl()
   {
     String paramName = "kaptcha.background.impl";
     String paramValue = this.properties.getProperty(paramName);
     BackgroundProducer backgroundProducer = (BackgroundProducer)this.helper.getClassInstance(paramName, paramValue, new DefaultBackground(), this);

     return backgroundProducer;
   }
 }

看config的源码就知道可以配置哪些属性了。

下面是spring boot的一个装配的实例代码：

import java.util.Properties;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import com.google.code.kaptcha.Producer;
import com.google.code.kaptcha.util.Config;

@Configuration
public class KaptchaConfig {

    @Bean
    public Producer KaptchaProducer() {
        Properties kaptchaProperties = new Properties();
        kaptchaProperties.put("kaptcha.border", "no");
        kaptchaProperties.put("kaptcha.textproducer.char.length","4");
        kaptchaProperties.put("kaptcha.image.height","50");
        kaptchaProperties.put("kaptcha.image.width","150");
        kaptchaProperties.put("kaptcha.obscurificator.impl","com.google.code.kaptcha.impl.ShadowGimpy");
        kaptchaProperties.put("kaptcha.textproducer.font.color","black");
        kaptchaProperties.put("kaptcha.textproducer.font.size","40");
        kaptchaProperties.put("kaptcha.noise.impl","com.google.code.kaptcha.impl.NoNoise");
        //kaptchaProperties.put("kaptcha.noise.impl","com.google.code.kaptcha.impl.DefaultNoise");
        kaptchaProperties.put("kaptcha.textproducer.char.string","acdefhkmnprtwxy2345678");

        Config config = new Config(kaptchaProperties);
        return config.getProducerImpl();
    }
}

使用的话常用的方法有：

package com.google.code.kaptcha;

import java.awt.image.BufferedImage;

public abstract interface Producer
{
  public abstract BufferedImage createImage(String kaptchaText);

  public abstract String createText();
}

得到BufferedImage可以写base64的格式的图片给前端，例如：

String kaptchaText = kaptchaProducer.createText();
log.info("capText = {} ,kaptchaKey = {} ", kaptchaText, kaptchaKey);
BufferedImage bi = kaptchaProducer.createImage(kaptchaText);

ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
ImageIO.write(bi, "jpeg", outputStream);
String base64Image = "data:image/jpeg;base64," + Base64.encodeBase64String(outputStream.toByteArray());