如果不想重复造轮子，参考上一篇文章：SpringBoot生成图形验证码_Muscleheng的博客-CSDN博客
这里不需要依赖开源组件包，完全自己实现图形验证码功能
两步完成：
package com.zhh.demo.common.util;
import lombok.extern.slf4j.Slf4j;
import org.apache.tomcat.util.codec.binary.Base64;
import org.springframework.stereotype.Component;
import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Random;
/**
* @Description: 图形验证码
* @Author: zhaoheng
* @CreateTime: 2022-12-09
*/
@Slf4j
@Component
public class GraphValidateCode {
//设置图片宽
private int width = 70;
//设置图片高度
private int height = 30;
//设置干扰线数量
private int lineSize = 40;
/** 随机产生数字和字母组合的字符串,字体只显示大写，去掉了1,0,i,o几个容易混淆的字符 */
public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ";
/**
* 获得字体
*/
private Font getFont() {
return new Font("Fixedsys", Font.CENTER_BASELINE, 18);
}
/**
* 获得颜色
*/
private Color getRandColor(int fc, int bc) {
Random random = new Random();
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);
}
/**
* 获取验证码
*
* @return
*/
public String getIdentifyCode() {
Random random = new Random();
StringBuffer buffer = new StringBuffer();
for (int i = 0; i < 4; i++) {
char c = VERIFY_CODES.charAt(random.nextInt(VERIFY_CODES.length()));
buffer.append(c);
}
return buffer.toString();
}
/**
* 生成随机图片
*
* @param identifyCode 图形码值
* @return
*/
public BufferedImage getIdentifyImage(String identifyCode) {
//BufferedImage类是具有缓冲区的Image类，Image类是用来描述图像信息的类
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
//产生Image对象的Graphics对象，改对象可以在图像上进行各种绘制操作
Graphics graphics = image.getGraphics();
//图片大小
graphics.fillRect(0, 0, width, height);
//字体大小
graphics.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 20));
//字体颜色
graphics.setColor(getRandColor(110, 133));
//绘制干扰线
for (int i = 0; i <= lineSize; i++) {
drawLine(graphics);
}
//绘制随机字符
drawString(graphics, identifyCode);
graphics.dispose();
return image;
}
/**
* 绘制字符串
* @param g 产生Image对象的Graphics对象
* @param identifyCode 图形码值
*/
private void drawString(Graphics g, String identifyCode) {
Random random = new Random();
for (int i = 0; i < identifyCode.length(); i++) {
g.setFont(getFont());
g.setColor(new Color(random.nextInt(101), random.nextInt(111), random
.nextInt(121)));
g.translate(random.nextInt(3), random.nextInt(3));
// x:图形码值基于图片最左边的距离
g.drawString(String.valueOf(identifyCode.charAt(i)), 13 * i + 8, 18);
}
}
/**
* 绘制干扰线
*/
private void drawLine(Graphics graphics) {
Random random = new Random();
int x = random.nextInt(width);
int y = random.nextInt(height);
int xl = random.nextInt(13);
int yl = random.nextInt(15);
graphics.drawLine(x, y, x + xl, y + yl);
}
/**
* 响应验证码图片
*
* @param identifyImg 图形码对象
* @param response
*/
public void responseIdentifyImg(BufferedImage identifyImg, HttpServletResponse response) {
//设置响应类型，告诉浏览器输出的内容是图片
response.setContentType("image/jpeg");
//设置响应头信息，告诉浏览器不用缓冲此内容
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expire", 0);
try {
//把内存中的图片通过流动形式输出到客户端
ImageIO.write(identifyImg, "JPEG", response.getOutputStream());
} catch (IOException e) {
log.error("图形验证码输出错误", e);
}
}
/**
* BufferedImage转base64
* @param img BufferedImage 对象
* @return
*/
public String getBase64FromImage(BufferedImage img) {
String base64 = "";
try (ByteArrayOutputStream stream = new ByteArrayOutputStream()) {
// 设置图片的格式
ImageIO.write(img, "jpg", stream);
byte[] bytes = Base64.encodeBase64(stream.toByteArray());
base64 = new String(bytes);
} catch (IOException e) {
log.error("图形验证码转base64错误", e);
}
return "data:image/jpeg;base64," + base64;
}
}
两个接口，两种方式：1.接口直接返回图片。2.接口返回base64字符串。
@Api(tags = "验证码-api")
@RequestMapping("/api/test")
@RestController
public class TestController {
// 模拟把验证码的值存储到缓存(记得添加过期时间)
Map<String,String> hashMap = new HashMap<>();
@Autowired
private GraphValidateCode graphValidateCode;
/**
* 给前端返回一个验证码图片
* @return
*/
@ApiOperation("获取图形验证码")
@GetMapping("/identifyImage")
public void identifyImage(HttpServletResponse response,
@ApiParam(value = "图形验证码id,无值：生成验证码，有值:刷新验证码")
@RequestParam(name = "codeId", required = false) String codeId) {
// 验证码
String identifyCode = graphValidateCode.getIdentifyCode();
// 模拟把验证码的值存储到缓存(记得添加过期时间)
if (codeId == null) {
System.out.println("获取图形码");
codeId = ToolUtil.simpleUUID();
// 保存图形码值
hashMap.put(codeId, identifyCode);
} else {
System.out.println("刷新图形码");
// 更新图形码值，此时此刻 图形码可能已经过期删除，那就相对于保存一个新的
hashMap.put(codeId, identifyCode);
}
// 图形验证码对应的UUID放在header中，前端可以拿到
response.setHeader("codeId", codeId);
//根据验证码创建图片
BufferedImage identifyImage = graphValidateCode.getIdentifyImage(identifyCode);
//回传给前端
graphValidateCode.responseIdentifyImg(identifyImage, response);
}
/**
* 给前端返回一个验证码图片-base64格式
* @return
*/
@ApiOperation("获取图形验证码-base64格式")
@GetMapping("/identifyImage2")
public String identifyImage2(
@ApiParam(value = "图形验证码id,无值：生成验证码，有值:刷新验证码")
@RequestParam(name = "codeId", required = false) String codeId) {
String identifyCode = graphValidateCode.getIdentifyCode();
// 模拟把验证码的值存储到缓存(记得添加过期时间)
if (codeId == null) {
System.out.println("获取图形码");
codeId = ToolUtil.simpleUUID();
// 保存图形码值
hashMap.put(codeId, identifyCode);
} else {
System.out.println("刷新图形码");
// 更新图形码值，此时此刻 图形码可能已经过期删除，那就相对于保存一个新的
hashMap.put(codeId, identifyCode);
}
//根据验证码创建图片
BufferedImage identifyImage = graphValidateCode.getIdentifyImage(identifyCode);
//回传给前端
System.out.println("新图形码值:" + identifyCode);
return graphValidateCode.getBase64FromImage(identifyImage);
}
}
