验证码
验证码的编写
package mall.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 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("/randomCode")
public class RandomCodeServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void service(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
//生成随机数
String randomCode = UUID.randomUUID().toString().substring(0, 5);
//把随机数放进Session中
req.getSession().setAttribute("RANDOMCODE_IN_SESSION", randomCode);
//创建图片对象
int width = 120;
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.PINK);
//绘制一个实心的矩形
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("微软雅黑", Font.BOLD + Font.ITALIC, 30);
g.setFont(font);//设置随机数的字体和大小
g.drawString(randomCode, 10, 28);
//干扰线
g.setColor(Color.GRAY);
Random r = new Random();
for (int i = 0; i < 100; 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());
}
}
前端页面
<%@ 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>
<script type="text/javascript">
function change(){
document.getElementById("randomCode").src="/randomCode?"+new Date().getTime();
}
</script>
</head>
<body>
<h1>用户登录</h1>
<span style="color:red;">${error}</span>
<form action="/dd" method="post">
用户名：<input type="text" name="name"/><br>
密 码<input type="password" name="pad"/><br>
验证码：<input type="text" name="randomCode" width="60%"/>
<img alt="" src="/randomCode" title="看不清？换一个" onclick="change()" id="randomCode">
<br>
<input type="submit" name="anniu" value="登录"/>
</form>
</body>
</html>
user类
package mall.domain;
import lombok.Data;
@Data
public class user {
private int id;
private String username;
private String password;
public user() {}
public user(String username, String password) {
this.username = username;
this.password = password;
}
}
servlet
package mall.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 mall.DAO.Iuserimpl;
import mall.DAO.impl.Iuser;
import mall.domain.user;
@WebServlet("/dd")
public class userser extends HttpServlet{
/**
*
*/
private static final long serialVersionUID = 1L;
private Iuser dao;
@Override
public void init() throws ServletException {
// TODO Auto-generated method stub
dao=new Iuserimpl();
}
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// TODO Auto-generated method stub
req.setCharacterEncoding("UTF-8");
String code=req.getParameter("randomCode");
String sessioncode=(String) req.getSession().getAttribute("RANDOMCODE_IN_SESSION");
if(code==null||"".equals(code)){
req.setAttribute("error", "验证码不能为空或验证码失效");
req.getRequestDispatcher("/login.jsp").forward(req, resp);
return;
}else if(!code.equals(sessioncode)){
req.setAttribute("error", "验证码错误");
req.getRequestDispatcher("/login.jsp").forward(req, resp);
return;
}
String name=req.getParameter("name");
String pad=req.getParameter("pad");
user u=new user(name,pad);
System.out.println(name+","+pad+","+dao.getone(u));
if(dao.getone(u)==null){
req.setAttribute("error", "密码或者账号错误");
req.getRequestDispatcher("/login.jsp").forward(req, resp);
return;
}
req.getSession().setAttribute("user", u);
req.getRequestDispatcher("/shopping.jsp").forward(req, resp);
}
}