如何快速生成图片验证码

   生成图片验证码是每个B/S架构项目的必备工具，该博文介绍如果快速、简单、生成实用的图片验证码；
  该工具类已经在多个项目中使用。

第三方依赖关系

  <dependency>
        <groupId>com.bladejava</groupId>
        <artifactId>blade-patchca</artifactId>
        <version>1.1.2</version>
    </dependency>
    
    <dependency>
       <groupId>cn.hutool</groupId>
       <artifactId>hutool-all</artifactId>
       <version>5.0.7</version>
   </dependency>
   
    <dependency>
       <groupId>org.projectlombok</groupId>
       <artifactId>lombok</artifactId>
       <version>1.18.12</version>
       <scope>provided</scope>
   </dependency>

核心代码

1. 生成图片验证码参数POJO类

import lombok.Data;

/**
 * @author huangrusheng
 * @version 1.0
 * @date 2021/5/20 9:55
 */
@Data
public class ImageCaptchaParams {
    /**
     * 默认图片验证码的文字内容
     */
    public static final String DEFAULT_WORDS = "123456789abcdefghjkmnpqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ";
    public static final String DEFAULT_FORMAT = "png";
    /**
     * 图片验证码宽度
     */
    private int width;
    /**
     * 图片验证码高度
     */
    private int height;
    /**
     * 最多生成几个文字
     */
    private int maxWordAmount;
    /**
     * 最小生成几个文字
     */
    private int minWordAmount;
    /**
     * 字体最大尺寸
     */
    private int maxFontSize;
    /**
     * 文字最小尺寸
     */
    private int minFontSize;
    /**
     * 生成图片验证码内容的字体
     */
    private String words;
    /**
     * 图片类型
     */
    private String format;

    public ImageCaptchaParams(){
        this.width = 200;
        this.height = 60;
        this.maxWordAmount = 5;
        this.minWordAmount = 4;
        this.minFontSize = 40;
        this.maxFontSize = 50;
        this.words = DEFAULT_WORDS;
        this.format = DEFAULT_FORMAT;
     }
  }

2.以IO流、Base64、Web的img标签识别的Base64方式输出图片验证码类

import cn.hutool.core.codec.Base64;
import org.patchca.color.SingleColorFactory;
import org.patchca.filter.predefined.CurvesRippleFilterFactory;
import org.patchca.font.RandomFontFactory;
import org.patchca.service.ConfigurableCaptchaService;
import org.patchca.utils.encoder.EncoderHelper;
import org.patchca.word.RandomWordFactory;
import java.awt.*;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
/**
 * @author huangrusheng
 * @version 1.0
 * @date 2021/5/20 9:54
 */
public final class ImageCaptchaUtil {

    private ImageCaptchaUtil(){}
    /**
     * 流方式输出
     * @param params
     * @param outputStream
     * @return 图片文字内容
     * @throws IOException
     */
    public static String create(ImageCaptchaParams params, OutputStream outputStream) throws IOException{
        ConfigurableCaptchaService  captchaService = new ConfigurableCaptchaService();
        captchaService.setColorFactory(new SingleColorFactory(Color.DARK_GRAY));
        captchaService.setFilterFactory(new CurvesRippleFilterFactory(captchaService.getColorFactory()));
        captchaService.setHeight(params.getHeight());
        captchaService.setWidth(params.getWidth());
        RandomWordFactory wordFactory = new RandomWordFactory();
        wordFactory.setCharacters(params.getWords());
        wordFactory.setMaxLength(params.getMaxWordAmount());
        wordFactory.setMinLength(params.getMinWordAmount());
        captchaService.setWordFactory(wordFactory);
        RandomFontFactory fontFactory = new RandomFontFactory();
        fontFactory.setMaxSize(params.getMaxFontSize());
        fontFactory.setMinSize(params.getMinFontSize());
        captchaService.setFontFactory(fontFactory);
        return EncoderHelper.getChallangeAndWriteImage(captchaService,params.getFormat(),outputStream);
    }
    /**
     * 以base64方式返回
     * @param params
     * @return 图片文字内容+base64格式的图片
     * @throws IOException
     */
    public static ImageCaptchaResult createBase64(ImageCaptchaParams params) throws IOException{
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream(1024 * 3);
        String words = create(params,outputStream);
        return new ImageCaptchaResult(words, Base64.encode(outputStream.toByteArray()));
    }
    /**
     * 以Web的img识别的base64返回
     * @param params
     * @return 图片文字内容+base64格式的img标签识别的图片
     * @throws IOException
     */
    public static ImageCaptchaResult createBase64ForWeb(ImageCaptchaParams params) throws IOException{
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream(1024 * 3);
        String words = create(params,outputStream);
        StringBuilder webImageSrc = new StringBuilder();
        webImageSrc.append("data:image/").append(params.getFormat().toLowerCase()).append(";base64,").append( Base64.encode(outputStream.toByteArray()));
        return new ImageCaptchaResult(words,webImageSrc.toString());
    }
}

3.生成图片验证码的返回结果

import lombok.AllArgsConstructor;
import lombok.Data;

/**
 * @author huangrusheng
 * @version 1.0
 * @date 2021/5/20 10:27
 */
@Data
@AllArgsConstructor
public class ImageCaptchaResult {
    /**
     * 图片验证码文字内容
     */
    private String words;
    /**
     * 返回内容，例如正常的Base64或以Web的image标签识别的base64格式
     */
    private String returnContent;


}

单元测试用例

import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
import java.io.FileOutputStream;
/**
 * @author huangrusheng
 * @version 1.0
 * @date 2021/5/20 10:13
 */
@RunWith(JUnit4.class)
public class ImageCaptchaTest {

    @Test
    public void testCreate() throws Exception{
        FileOutputStream fileOutputStream = new FileOutputStream("D:\\image_captcha.png");
        System.out.println(ImageCaptchaUtil.create(new ImageCaptchaParams(),fileOutputStream));
        fileOutputStream.close();
    }
    @Test
    public void testCreateBase64() throws Exception{
       ImageCaptchaResult result =  ImageCaptchaUtil.createBase64(new ImageCaptchaParams());
       System.out.println(result.getWords());
       System.out.println(result.getReturnContent());
    }
    @Test
    public void testCreateBase64ForWeb() throws Exception{
        ImageCaptchaResult result =  ImageCaptchaUtil.createBase64ForWeb(new ImageCaptchaParams());
        System.out.println(result.getWords());
        System.out.println(result.getReturnContent());
    }
}