java - 取消 JAVA JSP 上的预订

Question

我有一个简单的 Web 应用程序，可以在其中预订房间。如果我继续预订的房间，我会收到我已预订的房间的列表。 现在我想实现一个简单的按钮来删除特定的预订。 在我的数据库中，我有:

hotel_booking

使用此参数:

cid, cname, email, arrival_date, departure_date, person, room, type_room,comment, status, uid.

现在我已经创建了:

cancel.jsp

这是代码:

<%@page contentType="text/html" pageEncoding="UTF-8"%>
 <%@ page import ="java.sql.*" %>
 <%
int id;
int person;
int room;



id = Integer.parseInt(request.getParameter("id"));
//  out.println(id);
String cname  = request.getParameter("cname");
 // out.println(cname);
String email  = request.getParameter("email");
String arrival  = request.getParameter("arrival_date");
String departure  = request.getParameter("departure_date");
person = Integer.parseInt(request.getParameter("person"));
room = Integer.parseInt(request.getParameter("room"));

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

Class.forName("com.mysql.jdbc.Driver").newInstance();
Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/HotelReservation","root" ,"123456789");

String del = "delete from hotel_booking where id='" + Integer.parseInt(request.getParameter("id")) + "'AND cname='" + request.getParameter(cname) + "'AND emal='" + request.getParameter(email) + "'";

java.sql.Statement st = con.createStatement();

int rowNum = st.executeUpdate(del);
response.sendRedirect("home.jsp");
st.close();
%>

在 Booking.jsp 中，我插入了此表单作为取消按钮:

<form action='cancel.jsp'>
             <input type='submit' name='cancel' value='Cancel Reservation'>
             <input type="hidden" name="id" value=\""+id+"\">
            </form>
           </div>

但是我收到了这种错误:

HTTP Status 500 – Internal Server Error

Type Exception Report

Message An exception occurred processing [/cancel.jsp] at line [10]

Description The server encountered an unexpected condition that prevented it from fulfilling the request.

Exception

org.apache.jasper.JasperException: An exception occurred processing [/cancel.jsp] at line [10]

7: 
8: 
9: 
10: id = Integer.parseInt(request.getParameter("id"));
11: //  out.println(id);
12: String cname  = request.getParameter("cname");
13:  // out.println(cname);


Stacktrace:
    org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:593)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:482)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
Root Cause

java.lang.NumberFormatException: For input string: "\""+id+"\""
    java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
    java.lang.Integer.parseInt(Integer.java:580)
    java.lang.Integer.parseInt(Integer.java:615)
    org.apache.jsp.cancel_jsp._jspService(cancel_jsp.java:128)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:444)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
Note The full stack trace of the root cause is available in the server logs.

如何解决？每次有人预订房间时，我的数据库中的 cid 参数都会自动增加一。 谢谢大家

Answer 1

尝试下面的代码

<form action='cancel.jsp'>
 <input type="hidden" name="id" value="<%=id%>">
 <input type='submit' name='cancel' value='Cancel Reservation'>             
 </form>
</div>

因为 id 的值作为“\”“+id+”\“”传递。但是在您的代码中，您尝试解析包含非数值的字符串，因为 Integer 抛出 NumberFormatException。