ImageServlet.java
package cn.hist.test.servlet; 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.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession; public class ImageServlet extends HttpServlet{ // 生成随机颜色
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);
} public void doGet(HttpServletRequest request,HttpServletResponse response) throws IOException{
HttpSession session = request.getSession();
// 设置图形验证码中字符串的字体和大小
Font myFont = new Font("", Font.PLAIN, 25);
// 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 = 64, height = 41;
// 生成一张新图片
BufferedImage image=new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB);
Graphics g=image.getGraphics(); //通过缓冲区创建一个画布
Random random = new Random();
g.setColor(getRandColor(200, 250));//为画布创建背景颜色
g.fillRect(0, 0, width,height); //fillRect:填充指定的矩形
g.setColor(new Color(82, 82, 82)); //字体颜色
//g.drawRect(0, 0, width - 1, height - 1); //产生边框
g.setFont(myFont);
// 随机生成线条，让图片看起来更加杂乱
g.setColor(getRandColor(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
String sRand = "";
for (int i = 0; i < 6; i++) {
// 取得一个随机字符
String tmp = getRandomChar();
sRand += 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)));
//将验证码显示在图像中
g.drawString(tmp, 15 * i + 3, 30); //字体距左边及上边的距离
} // 将系统生成的图形验证码添加
session.setAttribute("rand", sRand);
g.dispose();
// 输出图形验证码图片
ImageIO.write(image, "JPEG", response.getOutputStream());
}
// 随机生成一个字符
private String getRandomChar() {
int rand = (int) Math.round(Math.random() * 2);// 将0～2的小数四舍五入生成整数
long itmp = 0;
char ctmp = '\u0000';
// 根据rand的值来决定是生成一个大写字母、小写字母和数字
switch (rand) {
// 生成大写字母的情形
case 1:
itmp = Math.round(Math.random() * 25 + 65);
ctmp = (char) itmp;
return String.valueOf(ctmp);
// 生成小写字母
case 2:
itmp = Math.round(Math.random() * 25 + 97);
ctmp = (char) itmp;
return String.valueOf(ctmp);
// 生成数字
default:
itmp = Math.round(Math.random() * 9);
return String.valueOf(itmp);
}
}
}
index.jsp
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<base href="<%=basePath%>">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<title>Test</title>
<link rel="stylesheet" href="">
<script>
//刷新验证码
function refresh() {
var time = new Date().getTime();
document.getElementById("imagecode").src = "ImageServlet?d=" + time;
}
</script>
</head>
<body>
<form action="ImageCompare">
<p>
<label for="icode">验证码</label><input type="text" name="icode"
id="icode" placeholder="请输入验证码" /><img alt="验证码"
id="imagecode" class="imagecode" src="ImageServlet"
onclick="refresh()" /><a href="javascript:void(0);"
onclick="refresh()">看不清？</a>
</p>
</form>
</body>
</html>
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<display-name></display-name>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>ImageServlet</servlet-name>
<servlet-class>cn.hist.test.servlet.ImageServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ImageServlet</servlet-name>
<url-pattern>/ImageServlet</url-pattern>
</servlet-mapping>
</web-app>
ImageCompare.java
package cn.hist.test.servlet; import java.io.IOException;
import java.io.PrintWriter; import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession; /**
* 比较输入的验证码是否正确
* @author Administrator
*
*/
public class ImageCompare extends HttpServlet{
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
PrintWriter out = resp.getWriter();
HttpSession session = req.getSession();
// 获取验证码中的字符
String rand = (String) session.getAttribute("rand");
System.out.println(rand);
String icode = req.getParameter("icode");
System.out.println(icode);
if (icode.equals(rand)) {
out.print("success");
}
else {
out.print("fail");
}
}
}
将rand与icode都转换成大写或小写再进行比较，实现输入验证码时不区分大小写