项目名称：/sessionVerificationCode
项目目录：
项目源码：
index.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<%=request.getAttribute("msg") %>
<form action="/sessionVerificationCode/RegisterServlet" method="post">
<input type="text" name="checkCode"></input>
验证码：
<img src="/sessionVerificationCode/VCodeGenerateServlet" onclick="this.src=‘/sessionVerificationCode/VCodeGenerateServlet?‘ + new Date()"><br>
<input type="submit" name="注册"></input>
</form>
</body>
</html>
success.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
注册成功
</body>
</html>
RegisterServlet.java
package com.ghsy.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class RegisterServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public RegisterServlet() {
super();
// TODO Auto-generated constructor stub
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("dopost RegisterServlet");
//1 获得数据
// * 用户提交
String checkCode = request.getParameter("checkCode");
// * 服务器缓存
String sessionBufferData = (String) request.getSession().getAttribute("sessionBufferData");
System.out.println("sessionBufferData:"+sessionBufferData);
System.out.println("checkCode"+checkCode);
//2比较
if(sessionBufferData != null){ //服务器有缓存
// * 完成一次性，将session缓存移除
request.getSession().removeAttribute("sessionBufferData");
if(sessionBufferData.equalsIgnoreCase(checkCode)){
// 用户输入正确
response.sendRedirect("success.jsp");
} else {
//不正确
request.setAttribute("msg", "验证码不正确，请重新输入");
request.getRequestDispatcher("/index.jsp").forward(request, response);
}
} else {
request.setAttribute("msg", "请不要重复提交");
request.getRequestDispatcher("/index.jsp").forward(request, response);
}
}
}
VCodeGenerateServlet.java
package com.ghsy.servlet;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.awt.image.ImageObserver;
import java.awt.image.ImageProducer;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class VCodeGenerateServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
//img标签生成图片的方式，是get请求
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("doget VCodeGenerateServlet");
//初始化图片的基本参数
int width=80;
int height=40;
String vcodeSource="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
Random random=new Random();
//创建一个rgb类型的图片
BufferedImage image=new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
//创建画板-图层
Graphics2D g=image.createGraphics();
//设置相关属性
g.setColor(Color.black);
g.fillRect(0, 0, width, height);//用当前的颜色填充画一个矩形
g.setColor(Color.white);
g.fillRect(1, 1, width-2, height-2);
g.setColor(Color.RED);
g.setFont(new Font("宋体", Font.BOLD, 20 ));
//在图片中写入字符
//#定义StringBuilder存储四个随机字符
StringBuilder sb=new StringBuilder();
//#随机的在vcodeSource字符串中选出四个字符，作为验证码
for (int i = 0; i < 4; i++) {
int index=random.nextInt(vcodeSource.length());
String str=vcodeSource.substring(index, index+1);
sb.append(str);
int rotateNum = random.nextInt(30);
//设置角度
g.rotate((rotateNum - 15) * Math.PI / 180 );
g.drawString(str, (width / 6) * (i+1), 20);
g.rotate(- ((rotateNum - 15) * Math.PI / 180 ));
}
//**#3 把生成数据放置session
String bufferData = sb.toString();
request.getSession().setAttribute("sessionBufferData", bufferData);
//生成图片的干扰线
for(int i = 0 ; i< 10 ; i++){
g.setColor(new Color(random.nextInt(255), random.nextInt(255), random.nextInt(255)));
g.drawLine(random.nextInt(width), random.nextInt(height), random.nextInt(width), random.nextInt(height));
}
//将服务器生成图片发送浏览器
ImageIO.write(image, "jpeg", response.getOutputStream());
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
}
}
Session技术案例-用户注册验证码,布布扣,bubuko.com
原文地址：http://blog.csdn.net/hymking/article/details/26262379
