1.规划登录实现原理流程图
2.编写前端页面
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html> <html> <head lang="en"> <meta charset="UTF-8"> <title>系统登录 - 超市订单管理系统</title> <link type="text/css" rel="stylesheet" href="${pageContext.request.contextPath }/css/style.css" /> <script type="text/javascript"> /* if(top.location!=self.location){ top.location=self.location; } */ </script> </head> <body class="login_bg"> <section class="loginBox"> <header class="loginHeader"> <h1>超市订单管理系统</h1> </header> <section class="loginCont"> <form class="loginForm" action="${pageContext.request.contextPath }/login.do" name="actionForm" id="actionForm" method="post" > <div class="info">${error }</div> <div class="inputbox"> <label for="userCode">用户名:</label> <input type="text" class="input-text" id="userCode" name="userCode" placeholder="请输入用户名" required/> </div> <div class="inputbox"> <label for="userPassword">密码:</label> <input type="password" id="userPassword" name="userPassword" placeholder="请输入密码" required/> </div> <div class="subBtn"> <input type="submit" value="登录"/> <input type="reset" value="重置"/> </div> </form> </section> </section> </body> </html>
<!--此仅仅是js,想要完整的评论留邮箱-->
3. 设置首页(登录页),将tomcat默认的index改成自己设计的首页
<!--设置欢迎页面--> <welcome-file-list> <welcome-file>login.jsp</welcome-file> </welcome-file-list>
4.编写dao层登录用户的接口
package com.king.dao.user; import com.king.pojo.User; import java.sql.Connection; import java.sql.SQLException; //面向接口编程,接口是一种约束,要用对应类去实现 public interface UserDao { //得到要登陆的用户 public User getLoginUser(Connection connection,String usercode) throws SQLException; }
5.编写登录接口的实现类
package com.king.dao.user; import com.king.dao.BaseDao; import com.king.pojo.User; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; //实现类,实现接口的方法 public class UserDaoImpl implements UserDao{ public User getLoginUser(Connection connection, String userCode) throws SQLException { PreparedStatement pstm=null; ResultSet rs=null; User user=null; if (connection!=null){ String sql="select * from smbms_user where userCode=?"; Object[] params={userCode}; rs = BaseDao.execute(connection, pstm, rs, sql, params); if(rs.next()){ user = new User(); user.setId(rs.getInt("id")); user.setUserCode(rs.getString("userCode")); user.setUserName(rs.getString("userName")); user.setUserPassword(rs.getString("userPassword")); user.setGander(rs.getInt("gender")); user.setBirthday(rs.getDate("birthday")); user.setPhone(rs.getString("phone")); user.setAddress(rs.getString("address")); user.setUserRole(rs.getInt("userRole")); user.setCreatedBy(rs.getInt("createBy")); user.setCreationDate(rs.getTimestamp("creationDate")); user.setModifyBy(rs.getInt("modifyBy")); user.setModifyDate(rs.getTimestamp("modifyDate")); } BaseDao.closeResource(null,pstm,rs); } return user; } }
6.业务层接口
package com.king.service.user; import com.king.pojo.User; public interface UserService { //用户登录 public User login(String userCode,String password); }
7.业务层接口的实现类
package com.king.service.user; import com.king.dao.BaseDao; import com.king.dao.user.UserDao; import com.king.dao.user.UserDaoImpl; import com.king.pojo.User; import java.sql.Connection; import java.sql.SQLException; public class UserServiceImpl implements UserService{ //业务层都会调用dao层,所以要引入dao层 private UserDao userDao; public UserServiceImpl(){ userDao=new UserDaoImpl(); } public User login(String userCode, String password) { Connection connection=null; User user=null; try { connection= BaseDao.getConnection(); //通过业务层调用对应的dao层 user = userDao.getLoginUser(connection, userCode); } catch (SQLException throwables) { throwables.printStackTrace(); }finally { BaseDao.closeResource(connection,null,null); } return user; } }
8 编写servlet层,与业务层链接实现数据交互
package com.king.servlet.user; import com.king.pojo.User; import com.king.service.user.UserService; import com.king.service.user.UserServiceImpl; import com.king.util.Constants; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; public class LoginServlet extends HttpServlet { //Servlet:控制层,调用业务层代码 @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { System.out.println("LoginServlet--start..."); //获取用户名和密码 String username= req.getParameter("userCode"); String userPassword= req.getParameter("userPassword"); //和数据库中的密码进行对比,调用业务层来实现 UserServiceImpl userService = new UserServiceImpl(); User user = userService.login(userPassword, userPassword);//已经把登录的人给查出来了 if (user!=null){//找到数据,可以登录 //将用户的信息放入session中 //为什么放session,区分用户角色,比如管理员,和普通用户 req.getSession().setAttribute(Constants.USER_SESSION,user); //跳转到主页 resp.sendRedirect("jsp/frame.jsp"); }else {//查无此人无法登录 //转发会登陆页面,同时提示错误 req.setAttribute("error","用户名或密码不正确"); req.getRequestDispatcher("login.jsp").forward(req,resp); } } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doGet(req, resp); } }
9 注册servlet
<!--Servlet--> <servlet> <servlet-name>LoginServlet</servlet-name> <servlet-class>com.king.servlet.user.LoginServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>LoginServlet</servlet-name> <url-pattern>/login.do</url-pattern> </servlet-mapping> <!--字符编码过滤器--> <filter> <filter-name>CharacterEncodingFilter</filter-name> <filter-class>com.king.filter.CharacterEncodingFilter</filter-class> </filter> <filter-mapping> <filter-name>CharacterEncodingFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <!--设置欢迎页面--> <welcome-file-list> <welcome-file>login.jsp</welcome-file> </welcome-file-list>
注意:当前只要是账号正确就可登录,代码验证后续补充
10,注销功能
package com.king.servlet.user; import com.king.util.Constants; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; public class LogoutServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { //移除用户的Constants.USER_SESSION req.getSession().removeAttribute(Constants.USER_SESSION); resp.sendRedirect("/login.jsp");//返回登陆页面 } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doGet(req, resp); } }
web配置,
<servlet> <servlet-name>LogoutServlet</servlet-name> <servlet-class>com.king.servlet.user.LogoutServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>LogoutServlet</servlet-name> <url-pattern>jsp/logout.do</url-pattern> </servlet-mapping>