Session 案例 验证码登录
1、需求
2、分析
3、编码
【1】编写登录页面
<%--
User: it春和
Date: 2022/2/24 23:19
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
<script>
// 点击图片切换验证码
window.onload = function () {
document.getElementById("img").onclick = function () {
var date = new Date();
this.src = "/13_session/checkCodeServlet?time=" + date.getTime();
}
}
</script>
</head>
<body>
<form action="/13_session/loginServlet" method="post">
<table>
<tr>
<td>用户名</td>
<td><input type="text" name="username" placeholder="请输入用户名"></input></td>
</tr>
<tr>
<td>密 码</td>
<td><input type="text" name="password" placeholder="请输入密码"></input></td>
</tr>
<tr>
<td>验证码</td>
<td><input type="text" name="checkcode" ></input></td>
</tr>
<tr>
<td colspan="2"><img src="/13_session/checkCodeServlet" id="img"></td>
</tr>
<tr>
<td colspan="2"><input type="submit" value="登录"></td>
</tr>
</table>
</form>
<div><%= request.getAttribute("error") == null ? "" : request.getAttribute("error") %></div>
<div><%= request.getAttribute("login_error") == null ? "" : request.getAttribute("login_error") %></div>
</body>
</html>
【2】将验证码存入session中
CheckCodeServet
package com.zhou.session.web;
/**
* @author it春和
* @create 2022-02-24 14:51
*/
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;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
// 动态生成验证码
@WebServlet("/checkCodeServlet")
public class CheckCodeServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
int width = 100;
int height = 50;
// TODO 1、创建一个对象 在内存中的图片 即验证码图片
BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
// TODO 2、美化图片
// 1、填充背景色
Graphics graphics = img.getGraphics(); // 画笔对象
graphics.setColor(Color.pink);
graphics.fillRect(0,0,width,height);
// 2、画边框
graphics.setColor(Color.red);
graphics.drawRect(0,0,width-1,height-1);
// 3、生成堆积验证码
graphics.setColor(Color.blue);
String str = "ABCDEFGHIGKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
Random random = new Random(); // 生成随机角标
StringBuilder sb = new StringBuilder();
for (int i = 1; i <= 4 ; i++) {
int index = random.nextInt(str.length());
// 获取字符
char c = str.charAt(index);
sb.append(c);
// 写验证码
graphics.drawString(c+"",width/5*i,height/2);
}
String checkCode_session = sb.toString(); // 生成的验证码
request.getSession().setAttribute("checkCode_session",checkCode_session); // 将生成的验证码存入session中
// 4、画干扰线
graphics.setColor(Color.GREEN);
for (int i = 0; i < 10; i++) {
int x1 = random.nextInt(width);
int x2 = random.nextInt(width);
int y1 = random.nextInt(height);
int y2 = random.nextInt(height);
graphics.drawLine(x1,y1,x2,y2);
}
// TODO 3、将图片输出
ImageIO.write(img,"jpg",response.getOutputStream());
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
1、实体类
package com.zhou.session.domain;
/**
* @author it春和
* @create 2022-02-24 11:12
*/
public class User {
private int id;
private String username;
private String password;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
'}';
}
}
2、userdao
// UserDao接口
public interface UserDao {
public User login(User user);
}
// 接口的实现类
public class UserDaoImpl implements UserDao {
// 使用jdbctemplate
private JdbcTemplate template = new JdbcTemplate(JdbcUtils.getDataSource());
@Override
public User login(User user) {
User f_user = null;
try {
String sql = "select * from user where username=? and password=?";
f_user = template.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), user.getUsername(), user.getPassword());
} catch (DataAccessException e) {
e.printStackTrace();
}
return f_user;
}
}
3、工具类 jdbcutils
public class JdbcUtils {
private static DataSource dataSource;
static {
// 加载配置文件
try {
Properties properties = new Properties();
InputStream is = JdbcUtils.class.getClassLoader().getResourceAsStream("druid.properties");
properties.load(is);
// 创建datasource
dataSource = DruidDataSourceFactory.createDataSource(properties);
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 获取datasource的方法
* @return datasource
*/
public static DataSource getDataSource(){
return dataSource;
}
/**
* 获取数据库连接对象
* @return conn
* @throws SQLException
*/
public Connection getConnection() throws SQLException {
return dataSource.getConnection();
}
}
4、loginServlet
package com.zhou.session.web; /**
* @author it春和
* @create 2022-02-25 0:02
*/
import com.zhou.session.dao.UserDao;
import com.zhou.session.dao.impl.UserDaoImpl;
import com.zhou.session.domain.User;
import org.apache.commons.beanutils.BeanUtils;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;
@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 1、获取请求参数 验证码
String checkcode = request.getParameter("checkcode");
Map<String, String[]> parameterMap = request.getParameterMap();
// 封装user对象
User user = new User();
try {
BeanUtils.populate(user,parameterMap);
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
// 获取服务器生成的验证码
String checkCode_session = (String) request.getSession().getAttribute("checkCode_session");
// 比较验证码
if (checkcode != null && checkcode.equalsIgnoreCase(checkCode_session)){
// 验证码匹配 匹配用户名密码 调用UserDao查询数据库
UserDao userDao = new UserDaoImpl();
User find_user = userDao.login(user);
if (find_user != null){
// 登陆成功 跳转到登录成功页面
response.setContentType("text/html;charset=utf-8");
response.getWriter().write("<h1>登录成功！</h1>");
}else{
// 登陆失败 跳转到登录页面
request.setAttribute("login_error","用户名或密码错误!");
request.getRequestDispatcher("/login.jsp").forward(request,response);
}
}else {
// 验证码不匹配
// 跳转到登录页面
request.setAttribute("error","验证码不匹配!");
request.getRequestDispatcher("/login.jsp").forward(request,response);
}
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
4、运行
