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