本文实例为大家分享了java验证码生成的示例代码，供大家参考，具体内容如下
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package com.gonvan.component.captcha;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
* Created by yuerzm on 2016/3/14.
*/
public class CaptchaFactory {
private static final char[] CODE_SEQUENCE = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
.toCharArray();
private static final int DEFAULT_WIDTH = 60;
private static final int DEFAULT_HEIGHT = 20;
private static final int DEFAULT_CODE_LEN = 4;
private static final int DEFAULT_CODE_X = 13;
private static final int DEFAULT_CODE_Y = 16;
private static final int DEFAULT_FONT_SIZE = 18;
private static final String DEFAULT_FONT_FAMILY = "Times New Roman";
private static CaptchaFactory instance = new CaptchaFactory();
private int height = DEFAULT_HEIGHT; // 定义图片的height
private int length = DEFAULT_CODE_LEN; // 定义图片上显示验证码的个数
private int xx = DEFAULT_CODE_X; // 定义图片上显示验证码x坐标
private int yy = DEFAULT_CODE_Y; // 定义图片上显示验证码y坐标
private int fontSize = DEFAULT_FONT_SIZE; // 定义图片上显示验证码的字体大小
private String fontFamily = DEFAULT_FONT_FAMILY; // 定义图片上显示验证码的个数
private CaptchaFactory() {
}
public static CaptchaFactory getInstance() {
return instance;
}
/**
* 配置宽高
*
* @param w
* @param h
* @return
*/
public CaptchaFactory configWidthAndHeight(int w, int h) {
instance.width = w;
instance.height = h;
return instance;
}
/**
* 配置坐标
*
* @param x
* @param y
* @return
*/
public CaptchaFactory configXY(int x, int y) {
instance.xx = x;
instance.yy = y;
return instance;
}
/**
* 配置字体大小
*
* @param fontSize
* @return
*/
public CaptchaFactory configFontSize(int fontSize) {
instance.fontSize = fontSize;
return instance;
}
/**
* 配置字体
*
* @param fontFamily
* @return
*/
public CaptchaFactory configFontSize(String fontFamily) {
instance.fontFamily = fontFamily;
return instance;
}
public void write(HttpServletRequest request, HttpServletResponse response) throws IOException {
// 将四位数字的验证码保存到Session中。
Map captcha = generate();
String randomCode = (String) captcha.get("captchaCode");
BufferedImage buffImg = (BufferedImage) captcha.get("captchaImg");
HttpSession session = request.getSession();
session.setAttribute("code", randomCode);
// 禁止图像缓存。
response.setHeader("Pragma", "no-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
response.setContentType("image/jpeg");
// 将图像输出到Servlet输出流中。
ServletOutputStream outputStream = response.getOutputStream();
ImageIO.write(buffImg, "jpeg", outputStream);
outputStream.close();
}
public Map<String, Object> generate() throws IOException {
// 定义图像buffer
BufferedImage buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics gd = buffImg.getGraphics();
// 设定背景色
gd.setColor(getRandColor(200, 250));
gd.fillRect(0, 0, width, height);
// 设定字体，字体的大小应该根据图片的高度来定。
gd.setFont(new Font(fontFamily, Font.PLAIN, fontSize));
// 创建一个随机数生成器类
Random random = new Random();
// 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(getRandColor(160, 200));
for (int i = 0; i < 155; 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 length 个验证码。
for (int i = 0; i < length; i++) {
// 得到随机产生的验证码数字。
String code = String.valueOf(CODE_SEQUENCE[random.nextInt(36)]);
// 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(110);
green = random.nextInt(110);
blue = random.nextInt(110);
// 用随机产生的颜色将验证码绘制到图像中。
gd.setColor(new Color(red + 20, green + 20, blue + 20));
gd.drawString(code, i * xx + 6, yy);
// 将产生的随机数组合在一起。
randomCode.append(code);
}
Map<String, Object> retval = new HashMap<>();
retval.put("captchaCode", randomCode.toString());
retval.put("captchaImg", buffImg);
return retval;
}
/**
* 给定范围获得随机颜色
*
* @param fc
* 最小值
* @param bc
* 最大值
* @return Color
*/
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);
int g = fc + random.nextInt(bc - fc);
int b = fc + random.nextInt(bc - fc);
return new Color(r, g, b);
}
}
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以上就是本文的全部内容，希望对大家的学习有所帮助。