servlet入门-04（使用JDBC连接数据库进行简单的注册）

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使用JDBC连接数据库进行用户注册

1.环境介绍

电脑：联想小新

软件：Eclipse

JDK版本：1.8

Tomcat版本：8.5

2. 背景

我们平时能够登陆是因为我们注册过，所以可以输入账号密码进行登陆，这次我们基于上一个登陆页面来写注册页面以及后台，顺便连接上我们的数据库将注册信息保存在数据库中。

3. 正文

首先，我们来理一理注册的步骤

我们首先要写一个注册的jsp页面
我们需要写一个servlet后台，用来处理注册功能
在后台我们要讲传过来的值存放在数据库中
注册完跳转到登陆页面，然后进行登陆以及判断
登陆成功展示个人信息

我们来实现第一步，写一个注册的jsp页面

<%@ 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>注册页面</title><style>*{  margin: 0;  padding: 0;  outline: none;  box-sizing: border-box;}html{  height: 100%;  background: linear-gradient(to bottom, #acb6e5, #86fde8);  display: flex;  justify-content: center;  align-items: center;}p {  text-align: center;  font-size: 34px;  font-weight: bold;  margin-bottom: 20px;  letter-spacing: 10px;}
form {  width: 600px;  font-size: 17px;  color: #434343;  font-family: "微软雅黑";  font-weight: 500;  background: rgba(230,255,251,0.4);  padding: 40px 110px;  border-radius: 20px;  box-shadow: 0 0 10px #d9d9d9;}
label {  height: 40px;  line-height: 40px;  display: block;}
span {  display: inline-block;  width: 80px;  text-align: center;}input,select{  height: 30px;  width:250px;  border-radius: 10px;  padding-left: 10px;  border: 1px solid #ffffff;  color: #434343;}input:hover,select:hover{  border: 1px solid #1890ff;  box-shadow: 0 0 5px #1890ff;}input[type="radio"]{  width: 20px;  height:13px;  vertical-align:center;  margin-left: 10px;}.submit{  border: 1px solid #1890ff;  background: #1890ff;  text-align: center;  width: 150px;  margin-left: 110px;  margin-top: 30px;  height: 40px;  letter-spacing: 10px;  color: #ffffff;}</style></head><body>  <form action="/Demo01/register" method="post" onsubmit="show()">  <p>注册页面</p>    <label class="user">      <span>账&nbsp;&nbsp;&nbsp;号：</span>      <input type="text" name="user" placeholder="请输入账号">    </label>    <label class="pass">      <span>密&nbsp;&nbsp;&nbsp;码：</span>      <input type="password" name="pass" placeholder="请输入密码">    </label>    <label class="name">      <span>姓&nbsp;&nbsp;&nbsp;名：</span>      <input type="text" name="name" placeholder="请输入姓名">    </label>    <label class="sex">       <span>性&nbsp;&nbsp;&nbsp;别：</span>        男<input type="radio" name="sex" value="male">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;        女<input type="radio" name="sex" value="female">    </label>    <label class="age">      <span>年&nbsp;&nbsp;&nbsp;龄：</span>      <input type="text" name="age" placeholder="请输入年龄">    </label>     <label class="tel">      <span>手机号：</span>      <input type="text" name="telephone" placeholder="请输入手机号">    </label>     <label class="address">      <span>地&nbsp;&nbsp;&nbsp;址：</span>      <input type="text" name="address" placeholder="请输入地址">    </label>    <label class="职业">       <span>职&nbsp;&nbsp;&nbsp;业：</span>       <select name="job">        <option value="teacher">教师</option>        <option value="Programmer">程序员</option>        <option value="boss">老板</option>      </select>    </label>        <input class="submit" type="submit" value="注册"/>      </form>  <script type="text/javascript">    function show() {      alert("提交表单！")    }</script></body></html>

写完以后我们去查看页面有没有成功，在地址栏输入localhost:8080/Demo01/views/register.jsp

然后第二步，我们去写处理注册功能的servlet，继承HttpServlet，重写doGet和doPost方法

第三步，连接数据库，把表单里的数据提交到数据库中，然后跳转到登陆页面。

package top.wangqi2020.demo;
import java.awt.print.Printable;import java.io.IOException;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.SQLException;
import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;
import top.wangqi2020.utils.JdbcUtils;
public class UserServlet02 extends HttpServlet{
  private static final long serialVersionUID = 1L;

  @Override  protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {    // TODO Auto-generated method stub    //修改接受和返回的编码格式    req.setCharacterEncoding("utf-8");    resp.setContentType("text/html;charset=utf-8");    Connection connection = null;    PreparedStatement preparedStatement = null;        try {      //连接数据库  获取连接对象      connection = JdbcUtils.getConnection();      //编写sql      String sql = "insert into t_user1(user,pass,name,sex,age,tele,address,job) values(?,?,?,?,?,?,?,?)";      //获取执行对象      preparedStatement = connection.prepareStatement(sql);      //给对象赋值      preparedStatement.setString(1, req.getParameter("user"));      preparedStatement.setString(2, req.getParameter("pass"));      preparedStatement.setString(3, req.getParameter("name"));      preparedStatement.setString(4, req.getParameter("sex"));      preparedStatement.setInt(5, Integer.parseInt(req.getParameter("age")));      preparedStatement.setString(6, req.getParameter("telephone"));      preparedStatement.setString(7, req.getParameter("address"));      preparedStatement.setString(8, req.getParameter("job"));            //执行sql      int count = preparedStatement.executeUpdate();      String msg = "";      if (count > 0) {        msg = "注册成功！";        System.out.println("注册成功！");      }else {        msg = "注册失败！";        System.out.println("注册失败！");      }          //设置给前端返回的信息      req.setAttribute("msg", msg);      //resp.sendRedirect("/Demo01/"); 跳转到注册状态页面      req.getRequestDispatcher("views/error.jsp").forward(req, resp);          } catch (SQLException e) {      // TODO Auto-generated catch block      e.printStackTrace();    }finally {      JdbcUtils.close(connection,  preparedStatement);    }  }    @Override  protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {    // TODO Auto-generated method stub    this.doGet(req, resp);  }}

我们还要在index.jsp中写一个跳转到注册页面的a标签

第四步，把UserServlet01中的doGet方法重新写一下，从数据库拿值来进行比较，跳转对应的页面

UserServlet01，处理登录请求

package top.wangqi2020.demo;import java.io.IOException;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;
import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;
import top.wangqi2020.utils.JdbcUtils;
/** * Servlet implementation class UserServlet01 *///@WebServlet("/UserServlet01")public class UserServlet01 extends HttpServlet {  private static final long serialVersionUID = 1L;           /**     * @see HttpServlet#HttpServlet()     */    public UserServlet01() {        super();        // TODO Auto-generated constructor stub    }
  /**   * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)   */  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {    //修改接受和返回的编码格式    request.setCharacterEncoding("utf-8");    response.setContentType("text/html;charset=utf-8");    Connection connection = null;    PreparedStatement preparedStatement = null;    ResultSet rs = null;            try {      //连接数据库  获取连接对象      connection = JdbcUtils.getConnection();      String sql = "select * from t_user1 where user=? and pass=?";      preparedStatement = connection.prepareStatement(sql);      String username = request.getParameter("username");      preparedStatement.setString(1, username);      preparedStatement.setString(2, request.getParameter("password"));      rs = preparedStatement.executeQuery();            if (rs.next()) {        request.setAttribute("username", rs.getString("name"));        //如果数据库中有数据，就跳转页面        request.getRequestDispatcher("views/success.jsp").forward(request, response);      }else {//        request.getRequestDispatcher("index.jsp").forward(request, response);        request.setAttribute("msg", "账户名或密码错误！");        request.getRequestDispatcher("views/error.jsp").forward(request, response);      }          } catch (SQLException e) {      // TODO Auto-generated catch block      e.printStackTrace();    }finally {      JdbcUtils.close(connection,  preparedStatement);    }  }
  /**   * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)   */  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {    // TODO Auto-generated method stub    this.doGet(request, response);  }
}