动手动脑——登录界面
1． 需要网站系统开发需要掌握的技术；
Java语言（Java database Connectivity（JjavawebDbc）技术、Servlet技术、jsp(Java Server Pages)技术，JavaBean(Application)应用组件技术）、面向对象分析设计思想、设计模式和框架结构、XML语言、网页脚本语言、开发工具（数据库、web服务器、集成开发环境（IDE））
2． 本次课堂测试的源程序代码；
User.java
package com.login.msg.model; public class User { private String name; private String password; public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } }
package com.login.msg.dao; import java.util.List; import com.login.msg.model.User; public interface IUserDao { public User login(String username); public List<User> load(); }
package com.login.msg.dao; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.List; import com.login.msg.Util.DBUtil; import com.login.msg.Util.UserException; import com.login.msg.model.User; import com.login.msg.Util.DBUtil; public class UserDaoImpl implements IUserDao{ //登录 @Override public User login(String username) { // TODO Auto-generated method stub Connection connection = DBUtil.getConnection(); //准备sql语句 String sql = "select * from t_user where username ="+"'"+username+"'";//定义一个查询语句 //创建语句传输对象 PreparedStatement preparedStatement = null; ResultSet resultSet = null; User user = null; try { preparedStatement = connection.prepareStatement(sql); preparedStatement.setString(1, username); resultSet = preparedStatement.executeQuery(); while(resultSet.next()) { if (resultSet.getInt(username) < 0) { throw new UserException("用户名或者密码失败") ; } } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); }finally { DBUtil.close(resultSet); DBUtil.close(preparedStatement); DBUtil.close(connection); } return user; } public List<User> load() { Connection connection = DBUtil.getConnection(); //准备sql语句 String sql = "select * from t_user "; //创建语句传输对象 PreparedStatement preparedStatement = null; ResultSet resultSet = null; //集合中只能放入user对象 List<User> users = new ArrayList<User>(); User user = null; try { preparedStatement = connection.prepareStatement(sql); resultSet = preparedStatement.executeQuery(); while(resultSet.next()) { user = new User(); user.setName(resultSet.getString("username")); user.setPassword(resultSet.getString("password")); users.add(user); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); }finally { DBUtil.close(resultSet); DBUtil.close(preparedStatement); DBUtil.close(connection); } return users; } }
package com.login.msg.Util; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Connection; public class DBUtil { public static Connection getConnection(){ //1 加载驱动 try { Class.forName("com.mysql.jdbc.Driver").newInstance(); } catch (InstantiationException | IllegalAccessException | ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } String user = "root"; String password = "root"; String url = "jdbc:mysql://localhost:3306/login_msg"; Connection connection = null; try { connection = DriverManager.getConnection(url,user,password); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return connection; } //关闭资源的方法 public static void close(Connection connection ) { try { if (connection != null) { connection.close(); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } public static void close(PreparedStatement preparedStatement ) { try { if (preparedStatement != null) { preparedStatement.close(); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } public static void close(ResultSet resultSet ) { try { if (resultSet != null) { resultSet.close(); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }
package com.login.msg.Util; public class UserException extends RuntimeException{ public UserException() { super(); // TODO Auto-generated constructor stub } public UserException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) { super(message, cause, enableSuppression, writableStackTrace); // TODO Auto-generated constructor stub } public UserException(String message, Throwable cause) { super(message, cause); // TODO Auto-generated constructor stub } public UserException(String message) { super(message); // TODO Auto-generated constructor stub } public UserException(Throwable cause) { super(cause); // TODO Auto-generated constructor stub } }
<%@page import="com.login.msg.Util.UserException"%> <%@page import="com.login.msg.dao.UserDaoImpl"%> <%@page import="com.login.msg.model.User"%> <%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <% //接收客户端传递过来的参数 String username = request.getParameter("username"); String password = request.getParameter("password"); if(username == null || "".equals(username.trim())){ request.setAttribute("error", "用户名不能为空"); %> <jsp:forward page="loginInput.jsp"></jsp:forward> <% } User user = new User(); user.setName(username); user.setPassword(password); UserDaoImpl userDao = new UserDaoImpl(); try{ userDao.login(username); //重定向 response.sendRedirect("list.jsp"); %> <% }catch(UserException e){ %> <h2 style="color:red ; font-size:50px">发生错误 : <%=e.getMessage() %></h2> <% } %> </html>
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <title>登录页面</title> </head> <body> <%=request.getAttribute("error") %> <form action="login.jsp" method="get"> <table align="center" border="1" width="500"> <tr> <td>用户名称 : </td> <td> <input type="text" name="username" /> </td> </tr> <tr> <td>用户密码:</td> <td> <input type="password" name="password" /> </td> </tr> <tr align="center"> <td colspan="2"> <input type="submit" value="登录" /> </td> </tr> </table> </form> </body> </html>
<%@page import="com.login.msg.model.User"%> <%@page import="java.util.List"%> <%@page import="com.login.msg.dao.UserDaoImpl"%> <%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>用户展示界面</title> </head> <% UserDaoImpl userDao = new UserDaoImpl(); List<User> users = userDao.load(); %> <body> <table align="center" border="1" width="500"> <tr> <td>用户名称</td> <td>用户密码</td> </tr> <% for( User user : users ){ %> <tr> <td> <%=user.getName() %></td> <td> <%=user.getPassword() %></td> <td> <a href="delete.jsp ? id="<%=user.getName() %>" >删除</a></td> </tr> <% } %> </table> </body> </html>
3． 运行结果截图；
4. 列出你对这门课的希望和自己的目标，并具体列出你计划每周花多少时间在这门课上。
能在八周之后单独完成一个简单的web应用；
每周14个小时
