Java生成随机验证码

package com.tg.snail.core.util;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.apache.log4j.Logger;
import org.springframework.util.StringUtils;
/**
* 验证码生成工具类
* @author penghy
* @date 2014-02-27
*/
public abstract class RandomCodeUtils {
private static Logger logger = Logger.getLogger(RandomCodeUtils.class);
private static final String RANDOM_CODE_KEY = "random"; //验证码放在session中的key
private static final int CODE_NUM = 4; //验证码字符个数
// 设置图形验证码中字符串的字体和大小
private static Font myFont = new Font("Arial", Font.BOLD, 16);
//随机字符数组
private static char[] charSequence = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".toCharArray();
private static Random random = new Random();
/**
* 生成随机验证码
* @param request
* @param response
*/
public static void createRandomCode(HttpServletRequest request, HttpServletResponse response){
// 阻止生成的页面内容被缓存，保证每次重新生成随机验证码
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
response.setContentType("image/jpeg");
// 指定图形验证码图片的大小
int width = 80, height = 25;
// 生成一张新图片
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
// 在图片中绘制内容
Graphics g = image.getGraphics();
g.setColor(getRandomColor(200, 250));
g.fillRect(1, 1, width - 1, height - 1);
g.setColor(new Color(102, 102, 102));
g.drawRect(0, 0, width - 1, height - 1);
g.setFont(myFont);
// 随机生成线条，让图片看起来更加杂乱
g.setColor(getRandomColor(160, 200));
for (int i = 0; i < 155; i++) {
int x = random.nextInt(width - 1);// 起点的x坐标
int y = random.nextInt(height - 1);// 起点的y坐标
int x1 = random.nextInt(6) + 1;// x轴偏移量
int y1 = random.nextInt(12) + 1;// y轴偏移量
g.drawLine(x, y, x + x1, y + y1);
}
// 随机生成线条，让图片看起来更加杂乱
for (int i = 0; i < 70; i++) {
int x = random.nextInt(width - 1);
int y = random.nextInt(height - 1);
int x1 = random.nextInt(12) + 1;
int y1 = random.nextInt(6) + 1;
g.drawLine(x, y, x - x1, y - y1);
}
// 该变量用来保存系统生成的随机字符串
StringBuilder sRand = new StringBuilder(CODE_NUM);
for (int i = 0; i < CODE_NUM; i++) {
// 取得一个随机字符
String tmp = getRandomChar();
sRand.append(tmp);
// 将系统生成的随机字符添加到图形验证码图片上
g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
g.drawString(tmp, 15 * i + 10, 20);
}
// 取得用户Session
HttpSession session = request.getSession(true);
// 将系统生成的图形验证码添加
session.setAttribute(RANDOM_CODE_KEY, sRand.toString());
g.dispose();
// 输出图形验证码图片
try {
ImageIO.write(image, "JPEG", response.getOutputStream());
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* 检查用户输入的验证码是否正确
* @param request
* @param inputCode
* @return true: 正确, false:不正确
*/
public static boolean checkRandomCode(HttpServletRequest request, String inputCode){
HttpSession session = request.getSession(false);
if(session != null && StringUtils.hasLength(inputCode)){
String code = (String) session.getAttribute(RANDOM_CODE_KEY);
logger.info("inputCode:"+inputCode.trim()+",code:"+code);
return inputCode.trim().equalsIgnoreCase(code);
}
return false;
}
/**
* 移除验证码
* @param request
* @param inputCode
*/
public static void removeRandomCode(HttpServletRequest request){
HttpSession session = request.getSession(false);
if(session != null){
session.removeAttribute(RANDOM_CODE_KEY);
}
}
// 生成随机颜色
private static Color getRandomColor(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);
}
// 随机生成一个字符
private static String getRandomChar() {
int index = random.nextInt(charSequence.length);
return String.valueOf(charSequence[index]);
}
}

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Java生成随机验证码

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