采用Servlet+JDBC+MySQL+Jsp完成一个登陆注册界面

最新推荐文章于 2022-02-28 20:22:21 发布

转载最新推荐文章于 2022-02-28 20:22:21 发布 · 7.4k 阅读

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文章标签：

#servlet #mysql #myeclipse #jdbc

本文介绍了一个使用Java Servlet和JSP实现的基本登录注册系统的构建过程，包括项目搭建、页面设计及数据库交互等内容。

首先介绍一下项目的环境:

myEclipse for Spring2014

Navicat : 用来管理MySQL数据库

Firefox浏览器:用来展现并调试页面

第一步：先创建一个web项目工程，(涉及到从数据库抓取数据展现到浏览器项目的均为Web Project)取个名字吧：LoginDemo，简要步骤如下：

File-New-Web Project

然后在上面视图中点击两次“下一步”后进入如下页面，勾选generate web.xml....,则可以自动在WebRoot/WEB-INF下生成一个web.xml文件

如下是自动生成的web.xml文件的内容：

接下来我们创建一个servlet,取名为LoginServlet，处理用户登录，步骤如下：

File-New-Servlet

点击下一步

点击上图完成，则一个登录的servlet创建完成了，但此时web.xml里没有自动给我们配置servlet，它是以注释的形式体现出来，如下图示：

所以为了能在web.xml里面自动配置servlet,我们需要采取其它方法。

在创建项目时，我们选择Dynamic Web Project, 2.5版本的支持web.xml里面自动配置servlet,3.0的不支持。

选择Dynamic Web Project, 2.5版本后，web.xml自动生成了servlet配置，如下图：

导入访问数据库的jar包

好了，准备工作基本结束了，现在开始上菜了：

第二步，编写代码了。

1>Login.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>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<style>
body {
   top: 20%;
   text-align: center
}

.div {
   top: 50%;
   margin: auto;
}
</style>

<title>Insert title here</title>


<script type="text/javascript">
   function login(form) {
       if (form.username.value == "") {
           alert("用户不能为空！");
           return false;
       }
       if (form.password.value == "") {
           alert("密码不能为空！");
           return false;
       }
   }
</script>

</head>
<body>
   <h1>登录</h1>
   <hr>
   <br>
   <br>
   <br>
   <div class="div">
       <form method="post" action="LoginServlet"
           onSubmit="return login(this);">
           <center>
               <table>
                   <tr>
                       <td>用户名:</td>
                       <td><input type="text" name="username"></td>
                   </tr>
                   <tr>
                       <td>密码:</td>
                       <td><input type="password" name="password"></td>
                   </tr>
               </table>
           </center>
           <br> <br> <input type="submit" value="点击登录"
               style="width: 120px; height: 33px; background: #ccc; color: black">
       </form>
   </div>

   <br>
   <br>

   <div id="Butten">
       <a href="zhuCe.jsp">还没有帐号??点击注册 ! !</a>
   </div>

   <br>
   <br>

</body>
</html>

2>LoginFailed.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    <html>
      <head>
        <title>登录失败</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">

      </head>

      <body>
            登录失败，请返回重新登录 <br>
            
            <form action="Login.jsp">
            <input type = "submit" value = "返回">
            </form>

      </body>
    </html>

3>LoginSuccess.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
    <title>登陆成功</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">

</head>

<body>
<center><h1>登录成功!!!!</h1></center>
<hr>
</body>
</html>

4>zhuCe.jsp

<%@ page language="java" pageEncoding="utf-8"%>
<%@ page contentType="text/html;charset=utf-8"%>
<%
   request.setCharacterEncoding("UTF-8");
   response.setCharacterEncoding("UTF-8");
   response.setContentType("text/html; charset=utf-8");
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>


<script type="text/javascript">
   function login(form) {
       if (form.username.value == "") {
           alert("ID不能为空！");
           return false;
       }
       if (form.password1.value == "") {
           alert("密码不能为空！");
           return false;
       }

       if (form.password1.value != form.password2.value) {
           alert("两次输入密码不一致!!!!！");
           return false;
       }

   }
</script>

</head>
<body>
   <center>
       <h1>注册:</h1>
       <HR>
       <form method="post" action="zhuCeServlet"
           onSubmit="return login(this);">
           ID :<br> <input type="text" name="username" value="" /><br>
           建议字母加上数字!! <br>
           <br> 密码 :<br> <input type="password" name="password1"
               value="" /> <br>
           <br> 再次输入密码 :<br> <input type="password" name="password2"
               value="" /> <br>
           <br> <input type="submit" value="点击注册" />

       </form>
   </center>
</body>
</html>

5>zhuCeSuccess.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
    <title>注册成功</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">
    

</head>

<body>
<center><h1>注册成功!!!!</h1></center>
<hr>
</body>

6>User.jsp

    package com.user;

    /*
     * 用户登录类，定义基本属性，用户名和密码
     */

    public class User {

        private String username;

        private String password;

        public String getUsername(){
            return this.username;
        }
        public void setUsername(String username){
            this.username = username;
        }

        public String getPassword(){
            return this.password;
        }
        public void setPassword(String password){
            this.password = password;
        }
    }

7>DBDao.java

package com.dao;

import java.sql.*;

public class DBDao {
    private static String USER = "root";
    private static String PASSWORD = "123456";
    private static String DB_URL = "jdbc:mysql://localhost:3306/logindemo";
    private static String DB_DRIVER = "com.mysql.jdbc.Driver";
    private static Connection connection = null;

    //连接数据库
    public static Connection getConnection(){

        try {
            Class.forName(DB_DRIVER);
            connection = DriverManager.getConnection(DB_URL, USER, PASSWORD);
        } catch (Exception e) {
            System.out.println("数据库连接异常");
            e.printStackTrace();
        }
        return connection;
    }
    public static void closeConnection(Connection connection){

                    if(connection != null){
                        try {
                            connection.close(); // 关闭数据库连接
                        } catch (SQLException e) {
                            e.printStackTrace();
                        }
                    }
                }
    }

8>UserDao.java

package com.dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import com.user.User;

public class UserDao {
   User user = null;
   private String SQL = "";

   public User login(String username, String password) {
       SQL = "select * from UserPWD where username = ? and password = ?";
       Connection connection = null;
       PreparedStatement pstmt = null;
       try {
           connection = DBDao.getConnection();
           pstmt = (PreparedStatement) connection.prepareStatement(SQL);
           // 这里的意思将用户名和密码填到SQL语句的问号处
           pstmt.setString(1, username);
           pstmt.setString(2, password);
           ResultSet rSet = (ResultSet) pstmt.executeQuery();//得到数据库的查询结果,一个数据集
           // 判断结果集是否有效
           if (rSet.next()) {
               user = new User();
               user.setUsername(rSet.getString("username"));
               user.setPassword(rSet.getString("password"));
           }
           pstmt.close();
           connection.close();

       } catch (Exception e) {

           e.printStackTrace();
       } finally {
           DBDao.closeConnection(connection);
       }
       return user;
   }

   public int zhuCe(String username, String password) {
       SQL = "insert into userpwd(username,password) values (?,?)";
        int b=0;
       Connection connection = null;
       PreparedStatement pstmt = null;
       try {

           connection = DBDao.getConnection();

           pstmt = connection.prepareStatement(SQL);

           pstmt.setString(1, username);
           pstmt.setString(2, password);

           b=pstmt.executeUpdate();
           System.out.println("---------"+b);
           pstmt.close();
           connection.close();
       } catch (Exception e) {
           e.printStackTrace();
       } finally {
           DBDao.closeConnection(connection);
       }
       return b;

   }

}

9>LoginServlet.java

package com.login.servlet;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.dao.UserDao;
import com.user.User;

public class LoginServlet extends HttpServlet {

   private static final long serialVersionUID = 1L;

   public void doPost(HttpServletRequest request, HttpServletResponse response)
           throws ServletException, IOException {
       response.setCharacterEncoding("utf-8");

       // 获取用户名和密码
       String username = request.getParameter("username");

       String password = request.getParameter("password");

       // 获取UserDao实例
       UserDao userDao = new UserDao();

       User user = userDao.login(username, password);
       // 判断user是否为空
       if (user != null) {
           // 转发到LoginSuccess.jsp页面
                       // getRequestDispatcher()是请求转发
           request.getRequestDispatcher("LoginSuccess.jsp").forward(request,
                   response);

       } else {
           // 登录失败
           request.getRequestDispatcher("LoginFailed.jsp").forward(request,
                   response);
       }

       System.out.println("-------******--------");
   }

   public void doGet(HttpServletRequest request, HttpServletResponse response)
           throws ServletException, IOException {
       doPost(request, response);
   }

}

10>zhuCeServlet.java

package com.login.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.dao.UserDao;

public class zhuCeServlet extends HttpServlet {
   private static final long serialVersionUID = 1L;

   public zhuCeServlet() {
       super();
   }

   protected void doGet(HttpServletRequest request,
           HttpServletResponse response) throws ServletException, IOException {
       doPost(request, response);
   }

   protected void doPost(HttpServletRequest request,
           HttpServletResponse response) throws ServletException, IOException {
       System.out.println("zhuCeServlet.java访问我啦");
       response.setCharacterEncoding("utf-8");

       // 获取用户名和密码
       String username = request.getParameter("username");

       System.out.println("username----->" + username);

       String password = request.getParameter("password1");
       System.out.println("password----->" + password);

       // 获取UserDao实例
       UserDao userDao = new UserDao();

       int i = userDao.zhuCe(username, password);
       System.out.println("-----" + i);
       // 判断i的值，为0表示未插入，为1表示插入一条数据
       if (i != 0) {
           System.out.println("-----------注册成功---------");
           request.getRequestDispatcher("zhuCeSuccess.jsp").forward(request,
                   response);
       } else {// 注册失败，仍然去注册页面操作
           System.out.println("000000000000000000000");
           request.getRequestDispatcher("zhuCe.jsp")
                   .forward(request, response);
       }
   }
}

11>web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
<display-name>LoginDemo</display-name>
<welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
</welcome-file-list>
<servlet>
    <description>my first servlet</description>
    <display-name>LoginServlet</display-name>
    <servlet-name>LoginServlet</servlet-name>
    <servlet-class>com.login.servlet.LoginServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
    <servlet-name>LoginServlet</servlet-name>
    <url-pattern>/LoginServlet</url-pattern>
</servlet-mapping>

<servlet>
    <servlet-name>zhuCeServlet</servlet-name>
    <servlet-class>com.login.servlet.zhuCeServlet</servlet-class>
    <load-on-startup>2</load-on-startup>
</servlet>
<servlet-mapping>
    <servlet-name>zhuCeServlet</servlet-name>
    <url-pattern>/zhuCeServlet</url-pattern>
</servlet-mapping>
</web-app>