html表单输入字段向mysql数据库添加空值

ht4b089n  于 2021-06-18  发布在  Mysql
关注(0)|答案(2)|浏览(531)

我有下面的html表单，用户可以在其中预订房间。我正试图获取用户在jsp代码中输入的数据，如图所示，但是数据库中的所有值都被添加为null，除了“user\u email”字段，该字段作为servlet发送的属性。我的代码有问题吗？如果是这样，我如何从这个表单的输入字段中获取值并将它们提交给下面的jsp代码。

  1. <%@ page language="java" contentType="text/html; charset=ISO-8859-1" import = "com.user.*"
  2.         pageEncoding="ISO-8859-1"%>
  3.     <!DOCTYPE html>
  4.     <html>
  5.     <head>
  6.     <meta charset="ISO-8859-1">
  7.     <title>Reservation</title>
  8.     </head>
  9.     <body>
  10.     <form  action="#">
  11.     <center>
  13.     <h3>Reservation</h3>
  14.     </center>
  15.     <table align="center" border="1">
  16.         <tr>
  17.             <td colspan="4" align="center">Please complete your reservation</td>
  18.         </tr>   
  20.         <tr>
  21.             <td>Arrival Date</td>
  22.             <td><select name="day" required>
  23.                 <option value="">--Day--</option>
  24.                 <option value="01">1</option>
  25.                 <option value="02">2</option>
  26.                 <option value="03">3</option>
  27.                 <option value="04">4</option>
  28.                 <option value="05">5</option>
  29.                 <option value="06">6</option>
  30.                 <option value="07">7</option>
  31.                 <option value="08">8</option>
  32.                 <option value="09">9</option>
  33.                 <option value="10">10</option>
  34.                 <option value="11">11</option>
  35.                 <option value="12">12</option>
  36.                 <option value="13">13</option>
  37.                 <option value="14">14</option>
  38.                 <option value="15">15</option>
  39.                 <option value="16">16</option>
  40.                 <option value="17">17</option>
  41.                 <option value="18">18</option>
  42.                 <option value="19">19</option>
  43.                 <option value="20">20</option>
  44.                 <option value="21">21</option>
  45.                 <option value="22">22</option>
  46.                 <option value="23">23</option>
  47.                 <option value="24">24</option>
  48.                 <option value="25">25</option>
  49.                 <option value="26">26</option>
  50.                 <option value="27">27</option>
  51.                 <option value="28">28</option>
  52.                 <option value="29">29</option>
  53.                 <option value="30">30</option>
  54.                 <option value="31">31</option>
  55.             </select>
  56.             <select name="month" required>
  57.                 <option value="">--Month--</option>
  58.                 <option value="01">Jan</option>
  59.                 <option value="02">Feb</option>
  60.                 <option value="03">Mar</option>
  61.                 <option value="04">Apr</option>
  62.                 <option value="05">May</option>
  63.                 <option value="06">Jun</option>
  64.                 <option value="07">Jul</option>
  65.                 <option value="08">Aug</option>
  66.                 <option value="09">Sep</option>
  67.                 <option value="10">Oct</option>
  68.                 <option value="11">Nov</option>
  69.                 <option value="12">Dec</option>
  70.             </select>
  71.             <select name="year" required>
  72.                 <option value="">--Year--</option>
  73.                 <option value="2018">2018</option>
  74.                 <option value="2019">2019</option>
  75.                 <option value="2020">2020</option>
  76.                 <option value="2021">2021</option>
  77.             </select></td>
  78.         </tr>
  79.         <tr>
  80.             <td>Number of rooms</td>
  81.             <td colspan="2"><input type="text" name="roomNo" id="roomNos"  required>
  82.                     </td>
  84.         </tr>
  85.         <tr>
  86.             <td>Number of nights</td>
  87.             <td colspan="2"><input type="text" name="nights" id="nightsNos" required>
  89.     </td>
  91.         </tr>
  93.         <tr>
  94.         <td>Room type:</td>
  95.         <td><select name="rType" required>
  96.           <option value="Single"> Single</option>
  97.           <option value="Double"> Double</option>
  98.           <option value="Triple"> Triple</option>
  99.           <option value="Suite"> Suite</option>
  100.         </select></td>
  101.         </tr>
  103.     </table><br>
  104.     <center><input type="submit" value="Add reservation" name="button" ></center>
  105.     </form>
  106.     <%  
  108.         String d = request.getParameter("day");
  109.         String m = request.getParameter("month");
  110.         String y = request.getParameter("year");
  111.         String r = request.getParameter("roomNo");
  112.         String n = request.getParameter("nights");
  113.         String rt = request.getParameter("rType");
  114.         String em = String.valueOf(request.getAttribute("email"));
  116.         ReservationDb rd = new ReservationDb();
  117.         rd.insert(d, m, y, r, n, rt, em);
  118.     %>
  120.     </body>
  121.     </html>

//插入函数

  1. public void insert(String d, String m, String y, String r, String n, String rt, String em) {
  2.             Connection connection = null;
  3.             PreparedStatement ppStm = null;
  5.             try {
  6.                 connection = ConnectionConfiguration.getConnection();
  7.                 ppStm = connection.prepareStatement("INSERT INTO reservations (res_day,res_month,res_year,no_rooms,"
  8.                         + "no_nights,room_type,user_email)"
  9.                         + "VALUES (?,?,?,?,?,?,?)");
  11.                 int count = 1;
  12.                 ppStm.setString(count++, d);
  13.                 ppStm.setString(count++, m);
  14.                 ppStm.setString(count++, y);
  15.                 ppStm.setString(count++, r);
  16.                 ppStm.setString(count++, n);
  17.                 ppStm.setString(count++, rt);
  18.                 ppStm.setString(count++, em);
  19.                 ppStm.executeUpdate();
  21.             } catch(Exception e) {
  22.                 e.printStackTrace();
  23.             } finally {
  25.                 if (ppStm != null){
  26.                     try {
  27.                         ppStm.close();
  28.                     } catch (SQLException e) {
  29.                         // TODO Auto-generated catch block
  30.                         e.printStackTrace();
  31.                     }
  33.                         }
  34.                 if (connection != null) {
  35.                         try {
  36.                             connection.close();
  37.                         } catch (SQLException e) {
  38.                             // TODO Auto-generated catch block
  39.                             e.printStackTrace();
  40.                     }
  41.                 }
  42.             }
  44.         }
JavamysqlHtmljspform-submit

2条答案

按热度按时间
agyaoht7

agyaoht71#

似乎您正在同一个定义输入表单的jsp页面上读取参数。
这没有错，但是在读取参数之前，您没有检查表单是否已提交。
简单的解决方案是：
检查请求中是否存在特定参数，
如果存在，则读取所有其他参数。
然后执行插入操作。
如果不存在，则不读取任何其他参数
不执行插入操作。
例子：

  1. <%  
  2.     String operation = request.getParameter("operation");
  3.     if ( operation != null and operation.equals( "addreservation" ) )
  4.     {
  5.         String d = request.getParameter("day");
  6.         String m = request.getParameter("month");
  7.         String y = request.getParameter("year");
  8.         String r = request.getParameter("roomNo");
  9.         String n = request.getParameter("nights");
  10.         String rt = request.getParameter("rType");
  11.         String em = String.valueOf(request.getAttribute("email"));
  13.         ReservationDb rd = new ReservationDb();
  14.         rd.insert(d, m, y, r, n, rt, em);
  15.     }
  16.     else
  17.     {
  18.         // ignore reading parameters
  19.     }
  20. ;
  21. %>
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赞(0）分享  回复(0）举报  2021-06-18
nwwlzxa7

nwwlzxa72#

  2. # Add this line in jsp page #
  4. <tr><td>Email</td><td><input name="email" required></td></tr>
  6. # Modify this line #
  8. String em = String.valueOf(request.getAttribute("email"));
  10. # Change with this code #
  12. String em = request.getParameter("email");
  14. # Kindly modify this and add condition like above answer.#
赞(0）分享  回复(0）举报  2021-06-18
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