SpringBoot登录验证码实现过程详解

<!-- https://mvnrepository.com/artifact/org.apache.commons/commons-lang3 -->
    <dependency>
      <groupId>org.apache.commons</groupId>
      <artifactId>commons-lang3</artifactId>
      <version>3.10</version>
    </dependency>

package com.youyou.login.util.validatecode;

import lombok.Data;

/**
* 验证码类
*/
public class VerifyCode {
  private String code;
  private byte[] imgBytes;
  private long expireTime;
  public String getCode() {
    return code;
  }
  public void setCode(String code) {
    this.code = code;
  }
  public byte[] getImgBytes() {
    return imgBytes;
  }
  public void setImgBytes(byte[] imgBytes) {
    this.imgBytes = imgBytes;
  }
  public long getExpireTime() {
    return expireTime;
  }
  public void setExpireTime(long expireTime) {
    this.expireTime = expireTime;
  }

}

package com.youyou.login.util.validatecode;

import java.io.IOException;
import java.io.OutputStream;

/**
* 验证码生成接口
*/
public interface IVerifyCodeGen {

/**
* 生成验证码并返回code，将图片写的os中
*
* @param width
* @param height
* @param os
* @return
* @throws IOException
*/
String generate(int width, int height, OutputStream os) throws IOException;

/**
* 生成验证码对象
*
* @param width
* @param height
* @return
* @throws IOException
*/
VerifyCode generate(int width, int height) throws IOException;
}

package com.youyou.login.util.validatecode;
import com.youyou.util.RandomUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
/**
* 验证码实现类
*/
public class SimpleCharVerifyCodeGenImpl implements IVerifyCodeGen {
	private static final Logger logger = LoggerFactory.getLogger(SimpleCharVerifyCodeGenImpl.class);
	private static final String[] FONT_TYPES = { "u5b8bu4f53", "u65b0u5b8bu4f53", "u9ed1u4f53", "u6977u4f53", "u96b6u4e66" };
	private static final int VALICATE_CODE_LENGTH = 4;
	/**
* 设置背景颜色及大小，干扰线
*
* @param graphics
* @param width
* @param height
*/
	private static void fillBackground(Graphics graphics, int width, int height) {
		// 填充背景
		graphics.setColor(Color.WHITE);
		//设置矩形坐标x y 为0
		graphics.fillRect(0, 0, width, height);
		// 加入干扰线条
		for (int i = 0; i < 8; i++) {
			//设置随机颜色算法参数
			graphics.setColor(RandomUtils.randomColor(40, 150));
			Random random = new Random();
			int x = random.nextint(width);
			int y = random.nextint(height);
			int x1 = random.nextint(width);
			int y1 = random.nextint(height);
			graphics.drawLine(x, y, x1, y1);
		}
	}
	/**
* 生成随机字符
*
* @param width
* @param height
* @param os
* @return
* @throws IOException
*/
	@Override
	public String generate(int width, int height, OutputStream os) throws IOException {
		BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
		Graphics graphics = image.getGraphics();
		fillBackground(graphics, width, height);
		String randomStr = RandomUtils.randomString(VALICATE_CODE_LENGTH);
		createCharacter(graphics, randomStr);
		graphics.dispose();
		//设置JPEG格式
		ImageIO.write(image, "JPEG", os);
		return randomStr;
	}
	/**
* 验证码生成
*
* @param width
* @param height
* @return
*/
	@Override
	public VerifyCode generate(int width, int height) {
		VerifyCode verifyCode = null;
		try (
		//将流的初始化放到这里就不需要手动关闭流
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		) {
			String code = generate(width, height, baos);
			verifyCode = new VerifyCode();
			verifyCode.setCode(code);
			verifyCode.setImgBytes(baos.toByteArray());
		}
		catch (IOException e) {
			logger.error(e.getMessage(), e);
			verifyCode = null;
		}
		return verifyCode;
	}
	/**
* 设置字符颜色大小
*
* @param g
* @param randomStr
*/
	private void createCharacter(Graphics g, String randomStr) {
		char[] charArray = randomStr.toCharArray();
		for (int i = 0; i < charArray.length; i++) {
			//设置RGB颜色算法参数
			g.setColor(new Color(50 + RandomUtils.nextint(100),
			+ RandomUtils.nextint(100), 50 + RandomUtils.nextint(100)));
			//设置字体大小，类型
			g.setFont(new Font(FONT_TYPES[RandomUtils.nextint(FONT_TYPES.length)], Font.BOLD, 26));
			//设置x y 坐标
			g.drawString(String.valueOf(charArray[i]), 15 * i + 5, 19 + RandomUtils.nextint(8));
		}
	}
}

package com.youyou.util;
import java.awt.*;
import java.util.Random;
public class RandomUtils extends org.apache.commons.lang3.RandomUtils {
	private static final char[] CODE_SEQ = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J',
	'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',
	'X', 'Y', 'Z', '2', '3', '4', '5', '6', '7', '8', '9' };
	private static final char[] NUMBER_ARRAY = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
	private static Random random = new Random();
	public static String randomString(int length) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < length; i++) {
			sb.append(String.valueOf(CODE_SEQ[random.nextint(CODE_SEQ.length)]));
		}
		return sb.toString();
	}
	public static String randomNumberString(int length) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < length; i++) {
			sb.append(String.valueOf(NUMBER_ARRAY[random.nextint(NUMBER_ARRAY.length)]));
		}
		return sb.toString();
	}
	public static Color randomColor(int fc, int bc) {
		int f = fc;
		int b = bc;
		Random random = new Random();
		if (f > 255) {
			f = 255;
		}
		if (b > 255) {
			b = 255;
		}
		return new Color(f + random.nextint(b - f), f + random.nextint(b - f), f + random.nextint(b - f));
	}
	public static int nextint(int bound) {
		return random.nextint(bound);
	}
}

@ApiOperation(value = "验证码")
@GetMapping("/verifyCode")
public void verifyCode(HttpServletRequest request, HttpServletResponse response) {
	IVerifyCodeGen iVerifyCodeGen = new SimpleCharVerifyCodeGenImpl();
	try {
		//设置长宽
		VerifyCode verifyCode = iVerifyCodeGen.generate(80, 28);
		String code = verifyCode.getCode();
		LOGGER.info(code);
		//将VerifyCode绑定session
		request.getSession().setAttribute("VerifyCode", code);
		//设置响应头
		response.setHeader("Pragma", "no-cache");
		//设置响应头
		response.setHeader("Cache-Control", "no-cache");
		//在代理服务器端防止缓冲
		response.setDateHeader("Expires", 0);
		//设置响应内容类型
		response.setContentType("image/jpeg");
		response.getOutputStream().write(verifyCode.getImgBytes());
		response.getOutputStream().flush();
	}
	catch (IOException e) {
		LOGGER.info("", e);
	}
}

<html>
<body>

<div>
<input id="code" placeholder="验证码" type="text" class=""
style="width:170px">
<!-- 验证码 显示 -->
<img οnclick="javascript:getvCode()" id="verifyimg" style="margin-left: 20px;"/>
</div>

<script type="text/javascript">
getvCode();

/**
* 获取验证码
* 将验证码写到login.html页面的id = verifyimg 的地方
*/
function getvCode() {
document.getElementById("verifyimg").src = timestamp("http://127.0.0.1:81/verifyCode");
}
//为url添加时间戳
function timestamp(url) {
var getTimestamp = new Date().getTime();
if (url.indexOf("?") > -1) {
url = url + "&timestamp=" + getTimestamp
} else {
url = url + "?timestamp=" + getTimestamp
}
return url;
};
</script>
</body>

</html>