需求
- 编写login登录界面(用户名，密码，验证码，登陆按钮，注册按钮)
- 设计关系数据库(编号，用户名，密码)
- 编写注册功能，将数据存储在数据库中。（姓名不能重复，设为主键，重复会注册失败）
- 编写登录功能 。首先获取验证码，先判断验证码是否正确，不正确则显示验证码错误。验证码正确后再获取用户名和密码，进行数据库的搜索比对，若正确则重定向到成功的界面，并且将用户名显示。
jar包
技术选型
Servlet + JSP + Mysql + JDBCTemplate + Druid + BeanUtils + Tomcat
效果图
验证码或者用户名和密码错误
Navicat Premium 显示Mysql内容
登录成功
注册功能
源码
登录主界面 login.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Login</title>
<script>
<%-- 增加时间戳来更换验证码图片 --%>
window.onload=function(){
document.getElementById("img").onclick=function(){
this.src = "/daydayup/checkCodeServlet?time" + new Date().getTime();
}
}
<%-- 用于打开注册的窗口--%>
function reg() {
window.open("register.jsp");
}
</script>
<style>
div{
color: red;
}
</style>
</head>
<body>
<form action="/daydayup/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="text" name="password"></td>
</tr>
<tr>
<td>验证码</td>
<td><input type="text" name="checkcode"></td>
</tr>
<tr>
<td colspan="2"><img id="img" src="/daydayup/checkCodeServlet" alt=""></td>
</tr>
<tr>
<td><input type="submit" value="登录"></td>
<td><input type="button" value="注册" onclick="reg()" ></td>
</tr>
</table>
</form>
<div>${requestScope.login_error}</div>
<div>${requestScope.checkcode_error}</div>
</body>
</html>注册界面 register.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<form action="/daydayup/registerServlet" 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="text" name="password"></td>
</tr>
<tr>
<td><input type="submit" value="确定注册"></td>
</tr>
</table>
</form>
<div>${requestScope.register_success}</div>
<div>${requestScope.register_error}</div>
</body>
</html>成功界面 success.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<%-- <h1>${requestScope.user},欢迎您</h1> --%>
<h1><%=request.getSession().getAttribute("user")%>,欢迎您</h1>
</body>
</html>先编辑好JDBCUtils工具类
package cn.code.util;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import javax.sql.DataSource;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;
/**
* JDBC工具类 使用Durid连接池
*/
public class JDBCUtils {
private static DataSource ds;
static{
try {
//加载配置文件
Properties pro = new Properties();
//使用ClassLoader加载配置文件，获取字节输入流
InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
pro.load(is);
//初始化连接池对象
ds = DruidDataSourceFactory.createDataSource(pro);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 获取连接池对象
*/
public static DataSource getDataSource(){
return ds;
}
/**
* 获取连接connection对象
*/
public static Connection getConnection() throws SQLException {
return ds.getConnection();
}
}创建我们的用户类实体User
package cn.code.domain;
/*
用户的实体类
*/
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 + '\'' +
'}';
}
}编写Dao来操作数据库，里面有login和add两个方法 Userdao
package cn.code.dao;
import cn.code.domain.User;
import cn.code.util.JDBCUtils;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;
/**
* 操作数据库中User表的类
*/
public class UserDao {
//声明JDBCTemplate对象，以便方法公用
private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());
/**
* 登录方法
*
* @param loginUser 目前只有用户名和密码
* @return user包含用户全部数据
*/
public User login(User loginUser) {
//编写SQL
String sql = "select * from user where username = ? and password = ?";
//调用query方法
try {
User user = template.queryForObject(sql,
new BeanPropertyRowMapper<User>(User.class),
loginUser.getUsername(), loginUser.getPassword());
return user;
} catch (DataAccessException e) {
e.printStackTrace();
return null;
}
}
/**
* 注册方法
*
* @param user 目前只包含用户名和密码
* @return 是否注册成功
*/
public boolean add(User user){
//编写SQL
String sql = "insert into user (username,password) VALUES('" + user.getUsername() + "','" + user.getPassword() + "')";
boolean flag = false;
int num = 0;
try {
//创建数据库连接
Connection conn = JDBCUtils.getConnection();
Statement state = null;
flag = false;
num = 0;
state = conn.createStatement();
num = state.executeUpdate(sql);
} catch (SQLException e) {
e.printStackTrace();
}
if(num >0) flag = true;
return flag;
}
}登录的Servlet
package cn.code.servlet;
import cn.code.dao.UserDao;
import cn.code.domain.User;
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 {
//设置字符编码
request.setCharacterEncoding("utf-8");
//获取参数
String username = request.getParameter("username");
String password = request.getParameter("password");
String checkcode = request.getParameter("checkcode");
//获取生成的验证码
HttpSession session = request.getSession();
String checkcode_session =(String) session.getAttribute("checkcode_session");
//防止验证码存储 删除Session中存储的验证码
session.removeAttribute("checkcode_session");
//判断验证码是否正确
if(checkcode_session != null && checkcode_session.equalsIgnoreCase(checkcode)){
//equalsIgnoreCase忽略大小写的比较
//验证码正确
User loginUser = new User();
loginUser.setUsername(username);
loginUser.setPassword(password);
User user = new UserDao().login(loginUser);
if(user != null){
//用户名以及密码正确
//登录成功
//存储用户信息
session.setAttribute("user",username); //因为是两次请求，所以用Session
//重定向到success.jsp
response.sendRedirect(request.getContextPath()+"/success.jsp");
}else{
//用户名及密码错误
//登录失败
//存储提示信息到request
request.setAttribute("login_error","用户名或密码错误");
//转发到登录页面
request.getRequestDispatcher("/login.jsp").forward(request,response);
}
}else{
//验证码不正确
//存储提示信息到request
request.setAttribute("checkcode_error","验证码错误");
//转发到登录页面
request.getRequestDispatcher("/login.jsp").forward(request,response);
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
}注册的Servlet
package cn.code.servlet;
import cn.code.dao.UserDao;
import cn.code.domain.User;
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.io.IOException;
@WebServlet("/registerServlet")
public class RegisterServlet 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");
User registerUser = new User();
registerUser.setUsername(username);
registerUser.setPassword(password);
boolean flag = new UserDao().add(registerUser);
if(flag) {
request.setAttribute("register_success","注册成功");
request.getRequestDispatcher("/register.jsp").forward(request,response);
}else{
request.setAttribute("register_error","账号以被注册,注册失败");
request.getRequestDispatcher("/register.jsp").forward(request,response);
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
}在页面中画验证码（可点击更换）Servlet
package cn.code.checkcode;
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;
//简易验证码
@WebServlet("/checkCodeServlet")
public class CheckCodeServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
int width = 100;
int height = 50;
//创建一对象，在内存中代表图片（验证码图片对象）
BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_BGR);
//美化图片
//填充背景色
Graphics g = image.getGraphics();//画笔对象
g.setColor(Color.ORANGE);
g.fillRect(0,0,width,height);
//画边框
g.setColor(Color.BLUE);
g.drawRect(0,0,width-1,height-1);
String str = "QWERTYUIOPASDFGHJKLZXCVBNM1234567890zxcvbnmlkjhgfdsaqwertyuiop";
//生成随机角标
StringBuilder sb = new StringBuilder();
Random ran = new Random();
for (int i = 1; i <= 4; i++) {
int index = ran.nextInt(str.length());
//获取字符
char ch = str.charAt(index);
sb.append(ch);
//写验证码
g.drawString(ch+"",width/5*i,height/2);
}
String checkcode_session = sb.toString();
//将验证码存入session
request.getSession().setAttribute("checkcode_session",checkcode_session);
//画干扰线
g.setColor(Color.RED);
//随机生成坐标点
for (int i = 0 ;i<6;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);
}
//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);
}
}
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