java生成圖形驗證碼

項目原來使用的驗證碼不夠清晰，參考了上面文章之後，将驗證碼改為字元串驗證。

先看一下修改前後的效果。

修改前：

修改後:

下面是修改後的代碼

POM(未寫出和驗證碼無關的内容)

<properties>
	<kaptcha.version>2.3.2</kaptcha.version>
</properties>

<dependency>
    <groupId>com.github.penggle</groupId>
	<artifactId>kaptcha</artifactId>
	<version>${kaptcha.version}</version>
	<exclusions>
		<exclusion>
			<artifactId>javax.servlet-api</artifactId>
			<groupId>javax.servlet</groupId>
		</exclusion>
	</exclusions>
</dependency>
           

前端頁面部分:

<div class="row" th:if="${captchaEnabled==true}">
	<div class="col-xs-6">
		<input type="text" name="validateCode" class="form-control code" placeholder="驗證碼" maxlength="5" autocomplete="off" style="margin-bottom: 5px;"/>
	</div>
	<div class="col-xs-6">
		<a href="javascript:void(0);" target="_blank" rel="external nofollow"  title="點選更換驗證碼">
		    <img th:src="@{captcha/captchaImage(type=${captchaType})}" class="imgcode" width="85%"/>
		</a>
	</div>
</div>
           

Controller（代碼中注釋掉的部分為原來的驗證碼邏輯，可以無視） 

package com.smart.project.system.user.controller;

import java.io.IOException;

import javax.annotation.Resource;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

import com.google.code.kaptcha.Producer;
import com.smart.framework.web.controller.BaseController;
import com.smart.project.system.user.utils.RandomValidateCodeUtils;

/**
 * 圖檔驗證碼（支援算術形式）
 * 
 * @author bcsmart
 */
@Controller
@RequestMapping("/captcha")
public class CaptchaController extends BaseController {

	/**
	 * 驗證碼生成
	 */
	@GetMapping(value = "/captchaImage")
	public ModelAndView getKaptchaImage(HttpServletRequest request, HttpServletResponse response) {
		ServletOutputStream out = null;
		try {
			// 設定響應頭資訊，告訴浏覽器不要緩存此内容
			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");
			// 設定相應類型,告訴浏覽器輸出的内容為圖檔
			response.setContentType("image/jpeg");
			RandomValidateCodeUtils randomValidateCodeUtils = new RandomValidateCodeUtils();
			// 輸出驗證碼圖檔方法
			randomValidateCodeUtils.getRandCode(request, response);

//			HttpSession session = request.getSession();
//			String type = request.getParameter("type");
//			String capStr = null;
//			String code = null;
//			BufferedImage bi = null;
//			if ("math".equals(type)) {
//				String capText = captchaProducerMath.createText();
//				capStr = capText.substring(0, capText.lastIndexOf("@"));
//				code = capText.substring(capText.lastIndexOf("@") + 1);
//				bi = captchaProducerMath.createImage(capStr);
//			} else if ("char".equals(type)) {
//				capStr = code = captchaProducer.createText();
//				bi = captchaProducer.createImage(capStr);
//			}
//			session.setAttribute(Constants.KAPTCHA_SESSION_KEY, code);
//			out = response.getOutputStream();
//			ImageIO.write(bi, "jpg", out);
//			out.flush();

		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				if (out != null) {
					out.close();
				}
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		return null;
	}
}
           

 繪制驗證碼的工具類

package com.smart.project.system.user.utils;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.code.kaptcha.Constants;

/**
 * 随機驗證碼生成工具類
 * 
 * @author sunbin
 * @since 2019年9月7日
 * @version 2019年9月7日
 */
public class RandomValidateCodeUtils {

	private static final Logger logger = LoggerFactory.getLogger(RandomValidateCodeUtils.class);

	/**
	 * 随機産生數字與字母組合的字元串(去掉了易混淆字元)
	 */
	private String randString = "23456789abcdefghjkmnpqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ";

	/**
	 * 圖檔寬
	 */
	private int width = 95;

	/**
	 * 圖檔高
	 */
	private int height = 35;

	/**
	 * 幹擾線數量
	 */
	private int lineSize = 20;

	/**
	 * 随機産生字元數量
	 */
	private int stringNum = 4;

	private Random random = new Random();

	/**
	 * 獲得字型
	 */
	private Font getFont() {
		return new Font("Fixedsys", Font.CENTER_BASELINE, 30);
	}

	/**
	 * 獲得顔色
	 */
	private Color getRandColor(int fc, int bc) {
		if (fc > 255) {
			fc = 255;
		}
		if (bc > 255) {
			bc = 255;
		}
		int r = fc + random.nextInt(bc - fc - 16);
		int g = fc + random.nextInt(bc - fc - 14);
		int b = fc + random.nextInt(bc - fc - 18);
		return new Color(r, g, b);
	}

	/**
	 * 生成随機圖檔
	 */
	public void getRandCode(HttpServletRequest request, HttpServletResponse response) {
		HttpSession session = request.getSession();
		// BufferedImage類是具有緩沖區的Image類,Image類是用于描述圖像資訊的類
		BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);

		// 産生Image對象的Graphics對象,改對象可以在圖像上進行各種繪制操作
		Graphics g = image.getGraphics();
		// 圖檔大小
		g.fillRect(0, 0, width, height);
		// 字型大小
		g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));
		// 字型顔色
		g.setColor(getRandColor(110, 133));
		// 繪制幹擾線
		for (int i = 0; i <= lineSize; i++) {
			drowLine(g);
		}
		// 繪制随機字元
		String randomString = "";
		for (int i = 1; i <= stringNum; i++) {
			randomString = drowString(g, randomString, i);
		}
		// 将生成的随機字元串儲存到session中
		session.setAttribute(Constants.KAPTCHA_SESSION_KEY, randomString);
		g.dispose();
		try {
			// 将記憶體中的圖檔通過流的形式輸出到用戶端
			ImageIO.write(image, "JPEG", response.getOutputStream());
		} catch (Exception e) {
			logger.error("将記憶體中的圖檔通過流的形式輸出到用戶端失敗", e);
		}

	}

	/**
	 * 繪制字元串
	 */
	private String drowString(Graphics g, String randomString, int i) {
		g.setFont(getFont());
		g.setColor(new Color(random.nextInt(101), random.nextInt(111), random.nextInt(121)));
		String rand = String.valueOf(getRandomString(random.nextInt(randString.length())));
		randomString += rand;
		g.translate(random.nextInt(3), random.nextInt(4));
		g.drawString(rand, 16 * i, 25);
		return randomString;
	}

	/**
	 * 繪制幹擾線
	 */
	private void drowLine(Graphics g) {
		int x = random.nextInt(width);
		int y = random.nextInt(height);
		int xl = random.nextInt(width);
		int yl = random.nextInt(height);
		g.drawLine(x, y, x + xl, y + yl);
	}

	/**
	 * 擷取随機的字元
	 */
	public String getRandomString(int num) {
		return String.valueOf(randString.charAt(num));
	}

}
           

參考文章 https://www.jianshu.com/p/45f9c4ffdeba