java常用验证码

## 写在前面（点击图片刷新）

<img alt="" src="/MyProject/captchaCodeServlet" onclick="refreshCode(this);"><br>

<script type="text/javascript">
//刷新验证码
function refreshCode(obj){
obj.src = "/MyProject/aptchaCodeServlet?time=" + new Date().getTime();
}
</script>

## 第一种、数字验证码
package com.bdqn.load;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
* 数字验证码
* @author ZhanShenxwd
*
*/
@WebServlet("/captchaCodeServlet")
public class CaptchaCodeServlet extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 1L;
//绘制字符的X轴坐标
private int x = 0;
// 设置验证码图片中显示的字体高度
private int fontHeight;
//绘制字符的Y轴坐标
private int codeY;
// 在这里定义了验证码图片的宽度
private int width = 100;
// 定义验证码图片的高度。
private int height = 30;
// 定义验证码字符个数，此处设置为4位
private int codeNum = 4;

Color getRandColor(int ff,int cc){
//给定范围获得随机颜色
Random random = new Random();
if(ff>255) ff=255;
if(cc>255) cc=255;
int r=ff+random.nextInt(cc-ff);
int g=ff+random.nextInt(cc-ff);
int b=ff+random.nextInt(cc-ff);
return new Color(r,g,b);
}


char[] codes = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A',
'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', };

/**
* 对验证图片属性进行初始化
*/
public void init() throws ServletException {
// 从部署文件web.xml中获取程序初始化信息，图片宽度跟高度，字符个数信息
// 获取初始化字符个数
String strCodeNums = this.getInitParameter("codeNum");
// 获取验证码图片宽度参数
String strW = this.getInitParameter("width");
// 获取验证码图片高度参数
String strH = this.getInitParameter("height");

// 将配置的字符串信息转换成数值类型数字
try {
if (strH != null && strH.length() != 0) {
height = Integer.parseInt(strH);
}
if (strW != null && strW.length() != 0) {
width = Integer.parseInt(strW);
}
if (strCodeNums != null && strCodeNums.length() != 0) {
codeNum = Integer.parseInt(strCodeNums);
}
} catch (NumberFormatException e) {
}
//控制字符的间距 - 2
x = width / (codeNum + 1) - 2;
fontHeight = height - 2;
codeY = height - 4;

}

protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, java.io.IOException {
// 定义验证码图像的缓冲流
BufferedImage buffImg = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
// 产生图形上下文
Graphics2D g = buffImg.createGraphics();

// 创建随机数产生函数
Random random = new Random();

// 将验证码图像背景填充为白色
g.setColor(getRandColor(210, 260));
g.fillRect(0, 0, width, height);

// 创建字体格式，字体的大小则根据验证码图片的高度来设定。
Font font = new Font("宋体", Font.PLAIN, fontHeight);
// 设置字体。
g.setFont(font);

// 为验证码图片画边框，为一个像素。
g.setColor(Color.BLACK);
// g.drawRect(0, 0, width - 1, height - 1);

// 随机生产100跳图片干扰线条，使验证码图片中的字符不被轻易识别
g.setColor(getRandColor(110, 240));
for (int i = 0; i < 100; i++) {
int x = random.nextInt(width);
int y = random.nextInt(height);
int xl = random.nextInt(12);
int yl = random.nextInt(12);
g.drawLine(x, y, x + xl, y + yl);
}

// randomCode保存随机产生的验证码
StringBuffer randomCode = new StringBuffer();

// 随机生产codeNum个数字验证码
for (int i = 0; i < codeNum; i++) {
// 得到随机产生的验证码
String strRand = String.valueOf(codes[random.nextInt(codes.length)]);
// 用随机产生的颜色将验证码绘制到图像中。
g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));
// 将随机字符写入到图像环境中
g.drawString(strRand, (i + 1) * x, codeY);
// 将产生的随机字符组合在一起。
randomCode.append(strRand);
}
// 将生产的验证码保存到Session中
HttpSession session = req.getSession();
session.setAttribute("validate", randomCode.toString());
// 设置图像缓存为no-cache。
resp.setHeader("Pragma", "no-cache");
resp.setHeader("Cache-Control", "no-cache");
resp.setDateHeader("Expires", 0);
resp.setContentType("image/jpeg");
// 将最终生产的验证码图片输出到Servlet的输出流中
ServletOutputStream sos = resp.getOutputStream();
ImageIO.write(buffImg, "jpeg", sos);
sos.close();
}

protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
doGet(req, resp);
}

}

## 第二种、成语验证码
[成语预览：] http://182.92.4.204/MuKeWang/words.txt

package com.bdqn.load;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
* 成语验证码
* @author ZhanShenxwd
*
*/
@WebServlet("/checkCodeServlet")
public class CheckCodeServlet extends HttpServlet {
private static final long serialVersionUID = 1L;

// 集合中保存所有成语
private List<String> words = new ArrayList<String>();

@Override
public void init() throws ServletException {
// 初始化阶段，读取new_words.txt
// web工程中读取 文件,必须使用绝对磁盘路径
String path = getServletContext().getRealPath("/WEB-INF/words.txt");
try {
BufferedReader reader = new BufferedReader(new FileReader(path));
String line;
//把读的成语全部添加到一个集合当中
while ((line = reader.readLine()) != null) {
words.add(line);
}
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 禁止缓存
response.setHeader("Cache-Control", "no-cache");
//设置过期时间为立即过期
response.setDateHeader("Expires", 0);

int width = 100;
int height = 30;
// 步骤一 绘制一张内存中图片
BufferedImage bufferedImage = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
// 步骤二 图片绘制背景颜色 ---通过绘图对象
Graphics graphics = bufferedImage.getGraphics();// 得到画图对象 --- 画笔
// 绘制任何图形之前 都必须指定一个颜色
graphics.setColor(getRandColor(200, 250));
graphics.fillRect(0, 0, width, height);
// 步骤三 绘制边框
graphics.setColor(Color.WHITE);
graphics.drawRect(0, 0, width - 1, height - 1);
// 步骤四 四个随机数字
Graphics2D graphics2d = (Graphics2D) graphics;
// 设置输出字体
graphics2d.setFont(new Font("宋体", Font.BOLD, 18));
Random random = new Random();// 生成随机数
int index = random.nextInt(words.size());
String word = words.get(index);// 获得成语
// System.out.println(word);
// 定义x坐标
int x = 10;
for (int i = 0; i < word.length(); i++) {
// 随机颜色
graphics2d.setColor(new Color(20 + random.nextInt(110), 20 + random
.nextInt(110), 20 + random.nextInt(110)));
// 旋转 -30 --- 30度
int jiaodu = random.nextInt(60) - 30;
// 换算弧度
double theta = jiaodu * Math.PI / 180;

// 获得字母数字
char c = word.charAt(i);

// 将c 输出到图片
graphics2d.rotate(theta, x, 20);
graphics2d.drawString(String.valueOf(c), x, 20);
graphics2d.rotate(-theta, x, 20);
//控制字符的间距
x += 22;
}

// 将验证码内容保存session
//request.getSession().setAttribute("checkcode_session", word);
//把生成的验证码存放到全局域对象当中
this.getServletContext().setAttribute("checkCode", word);
// 步骤五 绘制干扰线
graphics.setColor(getRandColor(160, 200));
int x1;
int x2;
int y1;
int y2;
for (int i = 0; i < 30; i++) {
x1 = random.nextInt(width);
x2 = random.nextInt(12);
y1 = random.nextInt(height);
y2 = random.nextInt(12);
graphics.drawLine(x1, y1, x1 + x2, x2 + y2);
}
// 将上面图片输出到浏览器 ImageIO
graphics.dispose();// 释放资源
//将图片写到response.getOutputStream()中
ImageIO.write(bufferedImage, "jpg", response.getOutputStream());
}

public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}

/**
* 取其某一范围的color
*
* @param fc
* int 范围参数1
* @param bc
* int 范围参数2
* @return Color
*/
private Color getRandColor(int fc, int bc) {
// 取其随机颜色
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);
}

}