jsp&servlet初体验——用户登录功能实现

数据库准备—创建db_login数据库  t_user表

1、创建web工程

2、创建用户model   user.java

 package com.gxy.model;

 public class User {
     private int id;
     private String userName;
     private String password;

     public User() {
         super();
     }

     public User(String userName, String password) {
         super();
         this.userName = userName;
         this.password = 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;
     }

 }

3、创建util包 Dbutil.java

 package com.gxy.util;

 import java.sql.Connection;
 import java.sql.DriverManager;

 public class Dbutil {
     private String dbUrl ="jdbc:mysql://localhost:3306/db_login";
     private String jdbcName="com.mysql.jdbc.Driver";
     private String dbUserName="root";
     private String dbpassword="123456";

     public Connection getcon() throws Exception{
         Class.forName(jdbcName);
         Connection con=DriverManager.getConnection(dbUrl,dbUserName,dbpassword);
         return con;
     }

     public void closeCon(Connection con) throws Exception{
         con.close();
     }

 }

4、创建dao包  UserDao.java

 package com.gxy.dao;

 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;

 import com.gxy.model.User;

 public class UserDao {
     public User login(Connection con,User user) throws Exception{
         User resultUser=null;
         String sql="select * from t_user where userName=? and passWord=?";
         PreparedStatement pst=con.prepareStatement(sql);
         pst.setString(1, user.getUserName());
         pst.setString(2,user.getPassword());
         ResultSet rs=pst.executeQuery();
         if(rs.next()){
             resultUser=new User();
             resultUser.setUserName(rs.getString("userName"));
             resultUser.setPassword(rs.getString("passWord"));
         }
         return resultUser;
     }

 }

5、创建servlet包  loginServlet

 package com.gxy.servlet;

 import java.io.IOException;
 import java.sql.Connection;

 import javax.servlet.RequestDispatcher;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpSession;

 import com.gxy.dao.UserDao;
 import com.gxy.model.User;
 import com.gxy.util.Dbutil;

 public class loginServlet extends HttpServlet{

     /**
      *
      */
     private static final long serialVersionUID = 1L;

     Dbutil dbutil=new Dbutil();
     UserDao userDao=new UserDao();
     @Override
     protected void doGet(HttpServletRequest req, HttpServletResponse resp)
             throws ServletException, IOException {
         this.doPost(req, resp);
     }

     @Override
     protected void doPost(HttpServletRequest req, HttpServletResponse resp)
             throws ServletException, IOException {
         String userName=req.getParameter("userName");
         String passWord=req.getParameter("passWord");

         Connection con=null;
         try {
             User user=new User(userName,passWord);
             con=dbutil.getcon();
             User resultUser=userDao.login(con, user);
             if(resultUser==null){
                 System.out.println("no");
             }else{
                 HttpSession session=req.getSession();
                 session.setAttribute("userName", resultUser.getUserName());
                 session.setAttribute("passWord", resultUser.getPassword());
                 resp.sendRedirect("target.jsp");
             }
         } catch (Exception e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }

     }

 }

6、用户登录界面  login.jsp

 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
 <%
 String path = request.getContextPath();
 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
 %>

 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 <html>
   <head>
     <base href="<%=basePath%>">

     <title>My JSP 'login.jsp' starting page</title>

     <meta http-equiv="pragma" content="no-cache">
     <meta http-equiv="cache-control" content="no-cache">
     <meta http-equiv="expires" content="0">
     <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
     <meta http-equiv="description" content="This is my page">
     <!--
     <link rel="stylesheet" type="text/css" href="styles.css">
     -->

   </head>

   <body>
   <form action="login" method="post">
     <table>
         <tr>
             <td>用户名：</td>
             <td><input type="text" id="userName" name="userName"></td>
         </tr>
         <tr>
             <td>密码：</td>
             <td><input type="password" id="passWord" name="passWord"></td>
         </tr>
         <tr>
             <td colspan="2"><input type="submit" value="提交" ></td>
         </tr>
     </table>
    </form>
   </body>
 </html>

跳转界面  target.jsp

 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
 <%
 String path = request.getContextPath();
 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
 %>

 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 <html>
   <head>
     <base href="<%=basePath%>">

     <title>My JSP 'target.jsp' starting page</title>

     <meta http-equiv="pragma" content="no-cache">
     <meta http-equiv="cache-control" content="no-cache">
     <meta http-equiv="expires" content="0">
     <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
     <meta http-equiv="description" content="This is my page">
     <!--
     <link rel="stylesheet" type="text/css" href="styles.css">
     -->

   </head>

   <body>
     <h1>用户名：<%=session.getAttribute("userName") %></h1>
     <h1>密码：<%=session.getAttribute("passWord") %></h1>
   </body>
 </html>

7、运行结果