java数字和中文算数验证码的实现

本文介绍了java数字和中文算数验证码的实现，分享给大家，具体如下：

效果图

本文代码 https://gitee.com/tothis/java-record/tree/master/src/main/java/com/example/captcha

中文实现参考 https://gitee.com/whvse/EasyCaptcha.git

数字实现参考 https://www.jb51.net/article/190561.htm

代码如下

中文算法

package com.example.captcha;

import lombok.extern.slf4j.Slf4j;

import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;

/**
 * @author 李磊
 * @datetime 2020/7/9 20:10
 * @description
 */
@Slf4j
public class ChineseCaptcha {
 // 宽度
 private static final int IMAGE_WIDTH = 160;
 // 高度
 private static final int IMAGE_HEIGHT = 40;
 // 字体大小
 private static final int FONT_SIZE = 28;
 // 干扰线数量
 private static final int IMAGE_DISTURB_LINE_NUMBER = 15;
 // 后缀
 private static final String SUFFIX = "等于？";

 // 汉字数字
 private static final String SOURCE = "零一二三四五六七八九十乘除加减";

 // 计算类型
 private static final Map<String, Integer> calcType = new HashMap<>();
 private static final Random RANDOM = new Random();

 static {
  // 对应SOURCE下标
  calcType.put("*", 11);
  calcType.put("/", 12);
  calcType.put("+", 13);
  calcType.put("-", 14);
 }

 // 计算公式
 private String content;
 // 计算结果
 private int result;

 /**
  * 生成图像验证码
  */
 public BufferedImage create() {
  createMathChar();
  BufferedImage image = new BufferedImage(IMAGE_WIDTH, IMAGE_HEIGHT, BufferedImage.TYPE_INT_RGB);
  Graphics g = image.getGraphics();
  // 字体颜色
  g.setColor(Color.WHITE);
  // 背景颜色
  g.fillRect(0, 0, IMAGE_WIDTH, IMAGE_HEIGHT);
  g.setColor(color());
  // 图片边框
  g.drawRect(0, 0, IMAGE_WIDTH - 1, IMAGE_HEIGHT - 1);
  g.setColor(color());
  for (int i = 0; i < IMAGE_DISTURB_LINE_NUMBER; i++) {
   // 绘制干扰线
   int x1 = RANDOM.nextInt(IMAGE_WIDTH);
   int y1 = RANDOM.nextInt(IMAGE_HEIGHT);
   int x2 = RANDOM.nextInt(13);
   int y2 = RANDOM.nextInt(15);
   g.drawLine(x1, y1, x1 + x2, y1 + y2);
  }
  StringBuilder builder = new StringBuilder();
  for (int i = 0, j = content.length(); i < j; i++) {
   int index;
   if (i == 1) {
    index = calcType.get(String.valueOf(content.charAt(i)));
   } else {
    index = Integer.parseInt(String.valueOf(content.charAt(i)));
   }
   String ch = String.valueOf(SOURCE.charAt(index));
   builder.append(ch);
   drawString((Graphics2D) g, ch, i);
  }
  drawString((Graphics2D) g, SUFFIX, 3);
  content = builder.append(SUFFIX).toString();
  g.dispose();
  return image;
 }

 private void createMathChar() {
  StringBuilder number = new StringBuilder();
  // 10以内数字
  int xx = RANDOM.nextInt(10);
  int yy = RANDOM.nextInt(10);
  // 0~3 对应加减乘除
  int round = (int) Math.round(Math.random() * 3);
  if (round == 0) {
   this.result = yy + xx;
   number.append(yy);
   number.append("+");
   number.append(xx);
  } else if (round == 1) {
   this.result = yy - xx;
   number.append(yy);
   number.append("-");
   number.append(xx);
  } else if (round == 2) {
   this.result = yy * xx;
   number.append(yy);
   number.append("*");
   number.append(xx);
  } else {
   // 0不可为被除数 yy对xx取余无余数
   if (!(xx == 0) && yy % xx == 0) {
    this.result = yy / xx;
    number.append(yy);
    number.append("/");
    number.append(xx);
   } else {
    this.result = yy + xx;
    number.append(yy);
    number.append("+");
    number.append(xx);
   }
  }
  this.content = number.toString();
  log.info("数字计算公式 {}", this.content);
 }

 private void drawString(Graphics2D g2d, String s, int i) {
  g2d.setFont(new Font("黑体", Font.BOLD, FONT_SIZE));
  int r = RANDOM.nextInt(255);
  int g = RANDOM.nextInt(255);
  int b = RANDOM.nextInt(255);
  g2d.setColor(new Color(r, g, b));
  int x = RANDOM.nextInt(3);
  int y = RANDOM.nextInt(2);
  g2d.translate(x, y);
  int angle = new Random().nextInt() % 15;
  g2d.rotate(angle * Math.PI / 180, 5 + i * 25, 20);
  g2d.drawString(s, 5 + i * 25, 30);
  g2d.rotate(-angle * Math.PI / 180, 5 + i * 25, 20);
 }

 // 获取随机颜色
 private Color color() {
  int r = RANDOM.nextInt(256);
  int g = RANDOM.nextInt(256);
  int b = RANDOM.nextInt(256);
  return new Color(r, g, b);
 }

 public String content() {
  return content;
 }

 public int result() {
  return result;
 }
}

数字算法

此代码使用了ttf字体 字体在此处 https://gitee.com/tothis/java-record/tree/master/src/main/resources/font

package com.example.captcha;

import lombok.SneakyThrows;

import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.Random;

/**
 * @author 李磊
 * @datetime 2020/7/9 20:16
 * @description
 */
public class NumberCaptcha {
 // 宽度
 private static final int IMAGE_WIDTH = 160;
 // 高度
 private static final int IMAGE_HEIGHT = 40;
 // 字体大小
 private static final int FONT_SIZE = 28;
 // 字体目录
 private static final String FONT_PATH = "/font/";
 // 字体列表
 private static final String[] FONT_NAMES = {
   "actionj.ttf", "epilog.ttf", "headache.ttf"
   , "lexo.ttf", "prefix.ttf", "robot.ttf"
 };

 private static final Random RANDOM = new Random();
 // 计算公式
 private String content;
 // 计算结果
 private int result;

 /**
  * 生成随机验证码
  */
 private void createMathChar() {
  StringBuilder number = new StringBuilder();
  int xx = RANDOM.nextInt(10);
  int yy = RANDOM.nextInt(10);
  // 0~3 对应加减乘除
  int round = (int) Math.round(Math.random() * 3);
  if (round == 0) {
   this.result = yy + xx;
   number.append(yy);
   number.append("+");
   number.append(xx);
  } else if (round == 1) {
   this.result = yy - xx;
   number.append(yy);
   number.append("-");
   number.append(xx);
  } else if (round == 2) {
   this.result = yy * xx;
   number.append(yy);
   number.append("x");
   number.append(xx);
  } else {
   // 0不可为被除数 yy对xx取余无余数
   if (!(xx == 0) && yy % xx == 0) {
    this.result = yy / xx;
    number.append(yy);
    number.append("/");
    number.append(xx);
   } else {
    this.result = yy + xx;
    number.append(yy);
    number.append("+");
    number.append(xx);
   }
  }

  content = number.append("=?").toString();
 }

 // 获取随机颜色
 private Color color() {
  int r = RANDOM.nextInt(256);
  int g = RANDOM.nextInt(256);
  int b = RANDOM.nextInt(256);
  return new Color(r, g, b);
 }

 /**
  * 随机画干扰圆
  *
  * @param num 数量
  * @param g Graphics2D
  */
 private void drawOval(int num, Graphics2D g) {
  for (int i = 0; i < num; i++) {
   g.setColor(color());
   int j = 5 + RANDOM.nextInt(10);
   g.drawOval(RANDOM.nextInt(IMAGE_WIDTH - 25), RANDOM.nextInt(IMAGE_HEIGHT - 15), j, j);
  }
 }

 @SneakyThrows
 private Font font() {
  int index = RANDOM.nextInt(FONT_NAMES.length);
  Font font = Font.createFont(Font.TRUETYPE_FONT
    , getClass().getResourceAsStream(FONT_PATH + FONT_NAMES[index]))
    .deriveFont(Font.BOLD, FONT_SIZE);
  return font;
 }

 /**
  * 生成验证码图形
  */
 public BufferedImage create() {
  createMathChar();
  char[] chars = content.toCharArray();
  BufferedImage image = new BufferedImage(IMAGE_WIDTH, IMAGE_HEIGHT, BufferedImage.TYPE_INT_RGB);
  Graphics2D g2d = (Graphics2D) image.getGraphics();
  // 填充背景
  g2d.setColor(Color.WHITE);
  g2d.fillRect(0, 0, IMAGE_WIDTH, IMAGE_HEIGHT);
  // 抗锯齿
  g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
  // 画干扰圆
  drawOval(2, g2d);
  // 画字符串
  g2d.setFont(font());
  FontMetrics fontMetrics = g2d.getFontMetrics();
  // 每一个字符所占的宽度
  int fx = IMAGE_WIDTH / chars.length;
  // 字符左填充
  int flp = 10;
  for (int i = 0; i < chars.length; i++) {
   String item = String.valueOf(chars[i]);
   g2d.setColor(color());
   // 文字的纵坐标
   int fy = IMAGE_HEIGHT - ((IMAGE_HEIGHT - (int) fontMetrics
     .getStringBounds(item, g2d).getHeight()) >> 1);
   g2d.drawString(item, flp + i * fx + 3, fy - 3);
  }
  g2d.dispose();
  return image;
 }

 public String content() {
  return content;
 }

 public int result() {
  return result;
 }
}

测试类

package com.example.captcha;

import com.greenpineyu.fel.FelEngine;
import com.greenpineyu.fel.FelEngineImpl;
import lombok.SneakyThrows;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;

/**
 * @author 李磊
 * @datetime 2020/7/9 20:10
 * @description
 */
public class Main {
 @SneakyThrows
 public static void main(String[] args) {
  // 图片类型
  String IMAGE_TYPE = "png";
  ChineseCaptcha chinese = new ChineseCaptcha();
  NumberCaptcha number = new NumberCaptcha();

  for (int i = 0; i < 10; i++) {
   BufferedImage image1 = chinese.create();
   // 输出文件
   ImageIO.write(image1, IMAGE_TYPE, new File("D:/data/a" + i + ".png"));
   System.out.println(chinese.content() + ' ' + chinese.result());

   BufferedImage image2 = number.create();
   // 输出文件
   ImageIO.write(image2, IMAGE_TYPE, new File("D:/data/b" + i + ".png"));
   System.out.println(number.content() + ' ' + number.result());
  }
 }
}

如需要多级运算如1+2-3*4/5 则需要使用表达式引擎计算 如下为使用fel计算表达式

// fel计算表达式
FelEngine fel = new FelEngineImpl();
System.out.println(3 * 2 + 1);
System.out.println(fel.eval("3*2+1"));
System.out.println(3 * (2 + 1));
System.out.println(fel.eval("3*(2+1)"));

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