java 验证码 生成

思维逻辑：

页面调用验证码生成方法，将验证码存放在session中，登录的时候 将输入验证码与session中的 相匹配

 

验证码生成类：

package com.hs.zhishiku.user.util;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
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 com.hs.zhishiku.sys.constants.Constant;

/**
* 生成验证码图片
* <p>
* Title: 应用模块名称
* </p>
* <p>
* Description: 代码描述
* </p>
* <p>
* Company:
* </p>
*
*/
public class RandomValidateCode {

private static Logger log = Logger.getLogger(RandomValidateCode.class);// 引入日志

public static final String RANDOMCODEKEY = "RANDOMVALIDATECODEKEY";// 放到session中的key
private Random random = new Random();
private String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";// 随机产生的字符串
private String checkCode = ""; // 要返回的随机字符串

private int width = 110;// 图片宽
private int height = 46;// 图片高
private int lineSize = 40;// 干扰线数量
private int stringNum = 6;// 随机产生字符数量
/*
* 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
*/
public void getRandcode(HttpServletRequest request, HttpServletResponse response) {
HttpSession session = request.getSession();
// 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);
g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));
g.setColor(getRandColor(110, 133));
// 绘制干扰线
for (int i = 0; i <= lineSize; i++) {
drowLine(g);
}
// 绘制随机字符
for (int i = 1; i <= stringNum; i++) {
checkCode = drowString(g, checkCode, i);
}
session.removeAttribute(RANDOMCODEKEY);
session.setAttribute(RANDOMCODEKEY, checkCode);

g.dispose();
try {
ImageIO.write(image, "JPEG", response.getOutputStream());// 将内存中的图片通过流动形式输出到客户端
} catch (Exception e) {
if (Constant.DEBUG) {
e.printStackTrace();
} else {
log.error("getRandcode", e);
}
}
}

/*
* 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(randString.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(randString.charAt(num));
}
}

 

 

调用方式：

public void getCode(HttpServletRequest req, HttpServletResponse resp) {
RandomValidateCode rc = new RandomValidateCode();
rc.getRandcode(req, resp);
}

 

验证是否相等的方式：

code.equalsIgnoreCase(((String) requst.getSession().getAttribute("RANDOMVALIDATECODEKEY")).substring(0, 6))