This article mainly introduces the method of java generating captcha image in detail. The sample code in the article is very detailed and has certain reference value. Interested friends can refer to it.
Example 1:
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.lang.RandomStringUtils;
import org.apache.commons.lang.StringUtils;
import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.util.Random;
public class RandomVerifyCode {
private static final String RANDOM_NUM = "23456789";
private static final String RANDOM_LETTER = "ABCDEFGHJKMNPQRSTUVWXYZ";
private static final String RANDOM_LETTER_SMALL = "abcdefghjkmnpqrstuvwxyz";
private static final String RANDOM_STRING = RANDOM_NUM + RANDOM_LETTER + RANDOM_LETTER_SMALL;
private int width = 95;// 图片宽
private int height = 25;// 图片高
private int lineSize = 40;// 干扰线数量
private int stringNum = 4;// 随机产生字符数量
private Random random = new Random();
/**
* 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) {
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);
}
/**
* 生成随机图片(BASE64格式)
*/
public String getRandcode(HttpServletRequest request, StringBuffer imgBuffer) {
// BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
Graphics g = image.getGraphics();// 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
g.fillRect(0, 0, width, height);//图片大小
g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));//字体大小
g.setColor(getRandColor(110, 133));//字体颜色
// 绘制干扰线
for (int i = 0; i <= lineSize; i++) {
drowLine(g);
}
// 绘制随机字符
String randomString = "";
for (int i = 1; i <= stringNum; i++) {
randomString = drowString(g, randomString, i);
}
g.dispose();
ByteArrayOutputStream out = new ByteArrayOutputStream();
String encode = null;
try {
// 将内存中的图片通过流动形式输出到客户端
ImageIO.write(image, "JPEG", out);
encode = "data:image/jpeg;base64,"+Base64.encodeBase64String(out.toByteArray());
out.close();
} catch (Exception e) {
LogHelper.error("登陆控制","验证码生成","将内存中生成的验证码图片输出为BASE64格式编码失败！");
}
imgBuffer.append(encode);
return randomString;
}
/**
* 绘制字符串
*/
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(RANDOM_STRING.length())));
randomString += rand;
g.translate(random.nextInt(3), random.nextInt(3));
g.drawString(rand, 13 * i, 16);
return randomString;
}
/**
* 绘制干扰线
*/
private void drowLine(Graphics g) {
int x = random.nextInt(width);
int y = random.nextInt(height);
int xl = random.nextInt(13);
int yl = random.nextInt(15);
g.drawLine(x, y, x + xl, y + yl);
}
/**
* 获取随机的字符
*/
public String getRandomString(int num) {
return String.valueOf(RANDOM_STRING.charAt(num));
}
public static String randomString(int length){
return RandomStringUtils.random(length, RANDOM_STRING.toCharArray());
}
}
Example two:
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.awt.image.RenderedImage;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;
public class CodeUtil {
private static int width = 90;// 定义图片的width 90
private static int height = 20;// 定义图片的height 20
private static int codeCount = 4;// 定义图片上显示验证码的个数
private static int xx = 15;
private static int fontHeight = 18;
private static int codeY = 16;
private static char[] codeSequence = {
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'M', 'N', 'P', 'Q', 'R',
'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '2', '3', '4', '5', '6', '7', '8', '9'};
public static Map<String,RenderedImage> codePicMap = new HashMap<>();
/**
* 生成一个map集合
* code为生成的验证码
* codePic为生成的验证码BufferedImage对象
*
* @return
*/
public static Map<String, Object> generateCodeAndPic() {
// 定义图像buffer
BufferedImage buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
// Graphics2D gd = buffImg.createGraphics();
// Graphics2D gd = (Graphics2D) buffImg.getGraphics();
Graphics gd = buffImg.getGraphics();
// 创建一个随机数生成器类
Random random = new Random();
// 将图像填充为蓝色
// gd.setColor(Color.WHITE);
gd.setColor(new Color(232,240,254));
gd.fillRect(0, 0, width, height);
// 创建字体，字体的大小应该根据图片的高度来定。
Font font = new Font("Fixedsys", Font.BOLD, fontHeight);
// 设置字体。
gd.setFont(font);
// 画边框。
gd.setColor(Color.BLACK);
gd.drawRect(0, 0, width - 1, height - 1);
// 随机产生40条干扰线，使图象中的认证码不易被其它程序探测到。
gd.setColor(Color.BLACK);
for (int i = 0; i < 10; i++) {
int x = random.nextInt(width);
int y = random.nextInt(height);
int xl = random.nextInt(12);
int yl = random.nextInt(12);
gd.drawLine(x, y, x + xl, y + yl);
}
// randomCode用于保存随机产生的验证码，以便用户登录后进行验证。
StringBuffer randomCode = new StringBuffer();
int red = 0, green = 0, blue = 0;
// 随机产生codeCount数字的验证码。
for (int i = 0; i < codeCount; i++) {
// 得到随机产生的验证码数字。
String code = String.valueOf(codeSequence[random.nextInt(31)]);
// 产生随机的颜色分量来构造颜色值，这样输出的每位数字的颜色值都将不同。
red = random.nextInt(255);
green = random.nextInt(255);
blue = random.nextInt(255);
// 用随机产生的颜色将验证码绘制到图像中。
gd.setColor(new Color(red, green, blue));
gd.drawString(code, (i + 1) * xx, codeY);
// 将产生的四个随机数组合在一起。
randomCode.append(code);
}
Map<String, Object> map = new HashMap<>();
//存放验证码
map.put("code", randomCode);
//存放生成的验证码BufferedImage对象
map.put("codePic", buffImg);
return map;
}
public static void main(String[] args) throws Exception {
//创建文件输出流对象
OutputStream out = new FileOutputStream("D://img/" + System.currentTimeMillis() + ".jpg");
Map<String, Object> map = CodeUtil.generateCodeAndPic();
ImageIO.write((RenderedImage) map.get("codePic"), "jpeg", out);
System.out.println("验证码的值为：" + map.get("code"));
}
}
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