1． 需要掌握的技术；
Java语言（Java database Connectivity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））
源代码：
1.DBUtil
package com.jaovo.msg.util; import java.sql.*; public class DBUtil {public static Connection getConnection() {try {//1 加载驱动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/jaovo_msg";Connection connection = null;try {//2 创建链接对象connectionconnection = 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();}} }
2.add.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%><%@ page import = "com.jaovo.msg.util.DBUtil" %> <%@ page import = "java.sql.*" %> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <%//接受客户端传递过来的参数String username = request.getParameter("username");if(username==null||"".equals(username)){request.setAttribute("哎呀", "请输入用户名!"); %><jsp:forward page="addInput.jsp"></jsp:forward><% }String password = request.getParameter("password");String sql="select * from t_user where username=?";Connection connection=DBUtil.getConnection();PreparedStatement preparedStatement=connection.prepareStatement(sql);preparedStatement.setString(1, username);ResultSet resultset=preparedStatement.executeQuery();boolean flag=false;while(resultset.next()){flag=true;if(resultset.getString("password").equals(password)){request.setAttribute("哎呀", "登陆成功，你是真的厉害!"); %><%=request.getAttribute("哎呀")%><% }else{request.setAttribute("哎呀", "登录失败，你好low!");%><jsp:forward page="addInput.jsp"></jsp:forward><% }}if(!flag){request.setAttribute("哎呀","用户不存在!");%><jsp:forward page="addInput.jsp"></jsp:forward><% }%> <body></body> </html>
3.addInput.jsp
<%@ 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>用户登录界面</title>
</head>
<body><form action="add.jsp" method="get"><%=request.getAttribute("哎呀") %><table align="center" border="1" width="500"><tr><td>用户名：</td><td><input type="text" name="username"/></td></tr><tr><td>输入密码：</td><td><input type="password" name="password"/></td></tr><tr align="center"><td colspan="2"><input type="submit" value="提交" /><input type="reset" value="重置" /></td></tr></table></form>>
</body>
</html>
