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生成图形验证码(算数运算图形验证码 + 随机字符图形验证码)
1 场景
在用户登录、忘记密码、用户注册、修改用户信息....等场景需要对用户进行图形化验证。防止别有用心的人或机器通过接口来进行攻击或恶意操作。
本示例讲解通过java生成两种图形验证码：算数运算的图形验证码和定长随机字符图形验证码！
2 编写代码
2.1 创建生成指定长度的随机字符串工具类
创建生成指定长度的随机字符串工具类：RandomCodeUtil.java，该工具类在之前的博客中讲到过。
import java.util.Random;
/**
* 生成指定长度的随机字符串
*/
public class RandomCodeUtil {
/**
* 生成指定长度的随机字符串(不包含数字0，和字母l、o和i)
*
* @param capacity 验证码长度
*/
public static String genCode(Integer capacity) {
//随机字符集(不包含数字0和字母o、i和l)
String str = "abcdefghjkmnpqrstuvwxyz123456789";
Random rand = new Random();
StringBuilder a = new StringBuilder();
for (int i = 0; i < capacity; i++) {
char c = str.charAt(rand.nextInt(str.length()));
a.append(c);
}
return a.toString();
}
public static void main(String[] args) {
//生产6位长度的随机验证码
System.out.println(RandomCodeUtil.genCode(6));
}
}
2.2 创建图形验证码工具类
创建图形验证码工具类：ImgCodeUtil.java
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
import javax.imageio.ImageIO;
/**
* 生成图形验证码工具类
*/
public class ImgCodeUtil {
/**
* 图片的宽度
*/
private Integer width = 120;
/**
* 图片的高度
*/
private Integer height = 40;
/**
* 验证码干扰线条数
*/
private Integer lineCount = 8;
/**
* 验证码code
*/
private String validateCode = null;
/**
* 验证码图片Buffer
*/
private BufferedImage buffImg = null;
/**
* 构造方法
*/
public ImgCodeUtil(String validateCode) {
this.validateCode = validateCode;
this.createCode();
}
/**
* 构造方法
*/
public ImgCodeUtil(String validateCode, int width, int height) {
this.width = width;
this.height = height;
this.validateCode = validateCode;
this.createCode();
}
/**
* 生成验证码图片
*/
private void createCode() {
int x = 0;
int fontHeight;
int codeY = 0;
int red = 0;
int green = 0;
int blue = 0;
int codeCount = validateCode.length();
//每个字符的宽度
x = width / codeCount;
//字体的高度
fontHeight = height - 2;
codeY = height - 4;
// 图像buffer
buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics2D g = buffImg.createGraphics();
// 生成随机数
Random random = new Random();
// 将图像填充为白色
g.setColor(Color.WHITE);
g.fillRect(0, 0, width, height);
//图片划线
for (int i = 0; i < lineCount; i++) {
int xs = random.nextInt(width / 2);
int ys = random.nextInt(height);
int xe = random.nextInt(width / 2) + width / 2;
int ye = random.nextInt(height);
red = random.nextInt(255);
green = random.nextInt(255);
blue = random.nextInt(255);
g.setColor(new Color(red, green, blue));
g.drawLine(xs, ys, xe, ye);
}
Font font = new Font("Arial", Font.BOLD, fontHeight);
g.setFont(font);
// 将验证码写入图片
for (int i = 0; i < codeCount; i++) {
red = random.nextInt(255);
green = random.nextInt(255);
blue = random.nextInt(255);
g.setColor(new Color(red, green, blue));
g.drawString(String.valueOf(validateCode.charAt(i)), i * x, codeY);
}
}
/**
* 输出图片到指定路径
*/
public void write(String path) throws IOException {
OutputStream outputStream = new FileOutputStream(path);
this.write(outputStream);
}
/**
* 将图片输出到输出流中
*/
public void write(OutputStream outputStream) throws IOException {
ImageIO.write(buffImg, "png", outputStream);
outputStream.close();
}
public BufferedImage getBuffImg() {
return buffImg;
}
}
2.3 创建图形验证码接口类
创建图形验证码接口类：ValidateCodeService.java
import com.xxx.alltest.dto.CheckCode;
import com.xxx.alltest.entity.ValidateCode;
/**
* 图形验证码接口类
*/
public interface ValidateCodeService {
/**
* 生成算数运算图形验证码
*/
ValidateCode generateMathImgCode(Integer width, Integer height);
/**
* 生成随机字符串图形验证码
*/
ValidateCode generateRandomImgCode(Integer width, Integer height);
/**
* 校验图形验证码值
*/
String checkValidateCode(CheckCode checkCode);
}
2.4 创建图形验证码接口实现类
图形验证码接口实现类：ValidateCodeServiceImpl.java
import com.xxx.alltest.dto.CheckCode;
import com.xxx.alltest.entity.ValidateCode;
import com.xxx.alltest.service.ValidateCodeService;
import com.xxx.alltest.utils.ImgCodeUtil;
import com.xxx.alltest.utils.RandomCodeUtil;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Objects;
import java.util.UUID;
import javax.imageio.ImageIO;
import lombok.extern.slf4j.Slf4j;
import mons.lang3.RandomUtils;
import org.springframework.stereotype.Service;
import org.springframework.util.Base64Utils;
import org.springframework.util.StringUtils;
/**
* 图形验证码接口实现类
*/
@Slf4j
@Service
public class ValidateCodeServiceImpl implements ValidateCodeService {
/**
* 验证码过期时间：5分钟
*/
private static final Long EXPIRE_TIME = 5 * 60 * 1000L;
/**
* 生成算数运算图形验证码
*/
@Override
public ValidateCode generateMathImgCode(Integer width, Integer height) {
Integer firstNum = RandomUtils.nextInt() % 10 + 1;
Integer secondNum = RandomUtils.nextInt() % 10 + 1;
Integer validateCode = firstNum + secondNum;
ImgCodeUtil imgCodeUtil = new ImgCodeUtil(firstNum + "+" + secondNum + "=?", width, height);
BufferedImage buffImg = imgCodeUtil.getBuffImg();
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
String base64ImgCode = null;
String uuid = UUID.randomUUID().toString().replaceAll("-", "");
try {
ImageIO.write(buffImg, "png", byteArrayOutputStream);
byte[] bytes = byteArrayOutputStream.toByteArray();
base64ImgCode = Base64Utils.encodeToString(bytes);
//将生成的验证码缓存起来
// redisTemplate.set(String.join(":", "mathImgCode", uuid), validateCode.toString(), EXPIRE_TIME);
} catch (IOException var10) {
log.error("生成算数运算图形验证码失败");
}
return ValidateCode.builder()
.base64ImgCode(base64ImgCode)
.uuid(uuid)
.build();
}
/**
* 生成随机字符串图形验证码
*/
@Override
public ValidateCode generateRandomImgCode(Integer width, Integer height) {
String validateCode = RandomCodeUtil.genCode(4);
ImgCodeUtil imgCodeUtil = new ImgCodeUtil(validateCode, width, height);
BufferedImage buffImg = imgCodeUtil.getBuffImg();
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
String base64ImgCode = null;
String uuid = UUID.randomUUID().toString().replaceAll("-", "");
try {
ImageIO.write(buffImg, "png", byteArrayOutputStream);
byte[] bytes = byteArrayOutputStream.toByteArray();
base64ImgCode = Base64Utils.encodeToString(bytes);
//将生成的验证码缓存起来
// redisTemplate.set(String.join(":", "randomImgCode", uuid), validateCode, EXPIRE_TIME);
} catch (IOException var10) {
log.error("生成随机字符串图形验证码失败");
}
return ValidateCode.builder()
.base64ImgCode(base64ImgCode)
.uuid(uuid)
.build();
}
/**
* 校验图形验证码值
*/
@Override
public String checkValidateCode(CheckCode checkCode) {
String redisCode = null;
// String redisCode = redisTemplate.get(String.join(":", "randomImgCode", checkCode.getUuid()));
if (StringUtils.isEmpty(redisCode)) {
return "验证码已过期";
}
if (!Objects.equals(checkCode.getValidateCode(), redisCode)) {
return "验证码错误";
}
return null;
}
}
2.5 创建验证码相关api接口类
创建验证码相关api接口类：ValidateCodeController.java
import com.xxx.alltest.mon.Result;
import com.xxx.alltest.dto.CheckCode;
import com.xxx.alltest.entity.ValidateCode;
import com.xxx.alltest.service.ValidateCodeService;
import java.util.Objects;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
/**
* 验证码相关api接口
*/
@RestController
@RequestMapping("/validate")
public class ValidateCodeController {
@Autowired
private ValidateCodeService validateCodeService;
/**
* 生成图形验证码
*
* @param type 0-普通字符图形验证码(如：1a4h) 1-算数图形验证码(1+8=?)
*/
@GetMapping("generate")
public Result generate(@RequestParam(value = "type", defaultValue = "0") String type,
@RequestParam(value = "width", defaultValue = "100") Integer width,
@RequestParam(value = "height", defaultValue = "40") Integer height) {
ValidateCode validateCode = null;
if (Objects.equals("0", type)) {
validateCode = validateCodeService.generateRandomImgCode(width, height);
} else {
validateCode = validateCodeService.generateMathImgCode(width, height);
}
if (StringUtils.isEmpty(validateCode.getBase64ImgCode())) {
return Result.failed("生成图形验证码失败");
} else {
return Result.ok(validateCode);
}
}
/**
* 校验图形验证码
*/
@PostMapping("check")
public Result check(@RequestBody CheckCode checkCode) {
String msg = validateCodeService.checkValidateCode(checkCode);
if (!StringUtils.isEmpty(msg)) {
return Result.failed(msg);
}
return Result.ok();
}
}
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