JavaWeb如何实现用户登录注册
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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> <%-- <h2>${requestScope.user},欢迎您</h2> --%> <h2><%=request.getSession().getAttribute("user")%>,欢迎您</h2> </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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