标签：是否一致 password mic 美化图片 page pat body orm stringbu
验证码案例:
需求:
1.访问带有验证码的登录页面login.js
2.用户输入用户名和密码
步骤:
1.设置request的编码
2.获取参数Map集合
3.获取验证码
4.将用户信息封装到User对象
5.判断程序生成的验证码和用户输入的验证码是否一致,从session中获取程序生成的验证码
*一致
在此判断用户名和密码是否一致(查询数据库)
正确:登录成功,存储数据,跳转到页面(重定向Session域)
不正确:给提示信息,跳转登录页面
*不一致
1.给用户提示信息,验证码错误 request
2.跳转登录页面 转发
LoginServlet
package com.infosys.session;
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 javax.servlet.http.HttpSession;
import java.io.IOException;
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
String username = request.getParameter("username");
String password = request.getParameter("password");
String checkCode = request.getParameter("checkCode");
HttpSession session = request.getSession();
String checkCode_session = (String) session.getAttribute("checkCode_session");
if (checkCode_session.equalsIgnoreCase(checkCode)) {
if ("zhangsan".equals(username) && "123".equals(password)) {
session.setAttribute("user", username);
response.sendRedirect(request.getContextPath() + "/success.jsp");
} else {
request.setAttribute("login_error", "用户名或密码错误");
request.getRequestDispatcher("/login.jsp").forward(request, response);
}
} else {
request.setAttribute("cc_error", "验证码错误");
request.getRequestDispatcher("/login.jsp").forward(request, response);
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
}
CheckCodeServlet
package com.infosys.servlet;
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;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
@WebServlet("/checkCodeServlet")
public class CheckCodeServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
int width = 100;
int height = 50;
//1.创建一对象，在内存中图片(验证码图片对象)
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
//2.美化图片
//2.1 填充背景色
Graphics g = image.getGraphics();//画笔对象
g.setColor(Color.PINK);//设置画笔颜色
g.fillRect(0, 0, width, height);
//2.2画边框
g.setColor(Color.BLUE);
g.drawRect(0, 0, width - 1, height - 1);
String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghigklmnopqrstuvwxyz0123456789";
//生成随机角标
Random ran = new Random();
StringBuilder sb = new StringBuilder();
for (int i = 1; i <= 4; i++) {
int index = ran.nextInt(str.length());
//获取字符
char ch = str.charAt(index);//随机字符
sb.append(ch);
//2.3写验证码
g.drawString(ch + "", width / 5 * i, height / 2);
}
String checkCode_session = sb.toString();
request.getSession().setAttribute("checkCode_session", checkCode_session);
//2.4画干扰线
g.setColor(Color.GREEN);
//随机生成坐标点
for (int i = 0; i < 10; i++) {
int x1 = ran.nextInt(width);
int x2 = ran.nextInt(width);
int y1 = ran.nextInt(height);
int y2 = ran.nextInt(height);
g.drawLine(x1, y1, x2, y2);
}
//3.将图片输出到页面展示
ImageIO.write(image, "jpg", response.getOutputStream());
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
}
login.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
<script>
window.onload = function () {
document.getElementById("img").onclick = function () {
this.src = "/cookie/checkCodeServlet?time=" + new Date().getTime();
}
}
</script>
</head>
<body>
<form action="/cookie/LoginServlet" method="post">
<table>
<tr>
<td>用户名</td>
<td><input type="text" name="username"/></td>
</tr>
<tr>
<td>密码</td>
<td><input type="password" name="password"/></td>
</tr>
<tr>
<td>验证码</td>
<td><input type="text" name="checkCode"/></td>
<td colspan="2"><img src="/cookie/checkCodeServlet" id="img"/></td>
</tr>
<tr>
<td colspan="2"><input type="submit" value="登录"/></td>
</tr>
</table>
</form>
<div><%= request.getAttribute("cc_error")%>
</div>
<div><%= request.getAttribute("login_error")%>
</div>
</body>
</html>
success.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<h1><%=request.getSession().getAttribute("user")%>,欢迎您</h1>
</body>
</html>
真实数据查询数据库
标签：是否一致 password mic 美化图片 page pat body orm stringbu
原文地址：https://www.cnblogs.com/jack-zhou21235/p/11285964.html
