验证码的实现
package zz.homework.controller;
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 java.util.UUID;
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;
@WebServlet("/verifyCode")
public class VerifyCodeServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void service(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
String str = "abcdefghjkmnpqrstuvwxyABCDEFGHJLMNPQRSTUVWXY123456789";
//生成随机数
Random r = new Random();
int codeCount = 5;//验证码字符个数
String verifyCode = "";
for(int i=0;i<codeCount;i++){
verifyCode += str.charAt(r.nextInt(str.length()));
}
//把随机数放进Session中
req.getSession().setAttribute("verifyCode", verifyCode);
//创建图片对象
int width = 80;
int height = 30;
int imageType = BufferedImage.TYPE_INT_RGB;
BufferedImage image = new BufferedImage(width, height, imageType);
//画板
Graphics g = image.getGraphics();
g.setColor(Color.WHITE);
//绘制一个实心的矩形[绘制边框]
g.fillRect(1, 1, width - 2, height - 2);
//把随机数画进图片中
g.setColor(Color.BLACK);//设置随机数的颜色
Font font = new Font("宋体", Font.BOLD + Font.ITALIC, 22);
g.setFont(font);//设置随机数的字体和大小
g.drawString(verifyCode, 10, 22);//绘制字符串
//干扰线
g.setColor(Color.GRAY);
for (int i = 0; i < 50; i++) {
g.fillRect(r.nextInt(width), r.nextInt(height), 2, 2);
}
//关闭
g.dispose();
//把图片对象以流的方式保存出去
ImageIO.write(image, "jpg", resp.getOutputStream());
}
}
前端界面参数
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>登录</title>
<style type="text/css">
table{width:150px; border: 1px solid gray; margin: auto;}
table tr{height:50px;}
</style>
<script type="text/javascript">
function changeImg(obj){
//确保后面的参数值不一样 随机数或者时间毫秒
obj.src = "verifyCode?xxx=" + new Date().getTime();//Math.random();
}
</script>
</head>
<body>
<form action="logServlet" method="post">
<table cellspacing="0">
<tr><th>登录</th></tr>
<tr><td><input type="text" name="userName" placeholder="用户名"/></td></tr>
<tr><td><input type="text" name="pwd" placeholder="密码"/><a style="color: red;">${msg}</a></td></tr>
<tr><td><input type="text" name="verifyCode" placeholder="验证码"/></td></tr>
<tr><td><img title="看不清楚？点击换一张" src="verifyCode" onclick="changeImg(this);" /><a style="color: red;">${errorMsg}</a></td></tr>
<tr><td><input type="submit" style="float: right;" value="登录"/>
<a href="register.jsp"><input type="button" style="float: left;" value="注册" /></a></td></tr>
</table>
</form>
</body>
</html>
登录的后台验证
package zz.homework.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import zz.homework.Dao.IUserDao;
import zz.homework.DaoImp.IUserDaoImp;
import zz.homework.domain.User;
import zz.homework.util.MyBeanUtils;
@WebServlet("/logServlet")
public class LogServlet extends HttpServlet {
private IUserDao userD = new IUserDaoImp();
@Override
protected void service(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
//处理乱码
req.setCharacterEncoding("utf-8");
//获取前台验证码
String verifyCode = req.getParameter("verifyCode");
//获取Session中保存的正确验证码
String verifyCode2 = (String)req.getSession().getAttribute("verifyCode");//比较
if(verifyCode2.equalsIgnoreCase(verifyCode)){
//获取请求参数 并且封装成JavaBean对象
User user = MyBeanUtils.getBean(req, User.class);
//调用dao层的方法
User user2 = userD.serachByName(user.getUserName());
//判断
if(null==user2){
req.setAttribute("msg","用户名不存在！请重试！！");
req.getRequestDispatcher("login.jsp").forward(req, res);
}else{
if(user2.getPwd().equals(user.getPwd())){
req.getSession().setAttribute("user",user2);
//跳转首页
res.sendRedirect("index.jsp");
}else{
req.setAttribute("msg","密码错误！！！");
req.getRequestDispatcher("login.jsp").forward(req, res);
}
}
}else{
//验证码错误
req.setAttribute("errorMsg","验证码错误！！");
req.getRequestDispatcher("login.jsp").forward(req, res);
}
}
}
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