我在下拉我的下拉选项值(它是一个数字)并将其拉到我的MySQL查询中时遇到一些问题。这是给您的一些代码:

users.jsp

<form method="post" action="insert-user.jsp">
<strong>Add User</strong>
<table>
<tr><td>First Name:</td><td><input type="text" name="fname"></td></tr>
<tr><td>Last Name:</td><td><input type="text" name="lname"></td></tr>
<tr><td>Account email:</td><td><input type="text" name="email"></td></tr>
<tr><td>Account password:</td><td><input type="password" name="pass"></td></tr>
<tr><td>Phone number:</td><td><input type="text" name="tno"></td></tr>
<tr><td>Group:</td><td><label for = "group"></label>
        <select name = "Group" id="group">
            <option value="1" selected>CSOTF-I</option>
            <option value="2">CSOTF-S</option>
            <option value="3">PACCOM</option></select></td></tr>
<tr><td>Role:</td><td><label for = "role"></label>
        <select name = "role" id="role">
            <option value="1" selected>Admin</option>
            <option value="2">FSR</option>
            <option value="3">Advisor</option></select></td></tr>
<tr><td>Notes:</td><td><input type="text" name="notes"></td></tr>
<tr><td></td><td><input type="submit" value="Submit"></td></tr>
</table>
</form>


和insert-user.jsp

<%@page import="java.sql.*,java.util.*"%>
<%
String fname=request.getParameter("fname");
String lname=request.getParameter("lname");
String email=request.getParameter("email");
String pass=request.getParameter("pass");
String tno=request.getParameter("tno");
int group=Integer.parseInt(request.getParameter("group"));
int role=Integer.parseInt(request.getParameter("role"));
String notes=request.getParameter("notes");


        try{
         Class.forName("com.mysql.jdbc.Driver");
           Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/raa", "root", "root");
           Statement st=con.createStatement();
           int i=st.executeUpdate("insert into tbluser(fname,lname,phone,email,password,notes,groupID,roleID) values('"+fname+"','"+lname+"','"+tno+"','"+email+"','"+pass+"','"+notes+"','"+group+"','"+role+"')");
        out.println("Data is successfully inserted!");
        response.sendRedirect("users.jsp");
        }
        catch(Exception e){
        System.out.print(e);
        e.printStackTrace();
        }
        %>


而我得到的500错误:


  HTTP状态[500] – [内部服务器错误]
  
  类型异常报告
  
  消息处理JSP页面[/insert-user.jsp]发生异常
  在第[8]行
  
  说明服务器遇到意外情况,该情况是
  阻止其满足请求。
  
  异常org.apache.jasper.JasperException:发生异常
  在第[8]行处理JSP页面[/insert-user.jsp]
  
  5:字符串email = request.getParameter(“ email”); 6:弦
  pass = request.getParameter(“ pass”); 7:弦
  tno = request.getParameter(“ tno”); 8:整数
  group = Integer.parseInt(request.getParameter(“ group”)); 9:整数
  role = Integer.parseInt(request.getParameter(“ role”)); 10:弦
  notes = request.getParameter(“ notes”); 11:
  
  堆栈跟踪:
    org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:588)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:481)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
  
  根本原因java.lang.NumberFormatException:null
    java.lang.Integer.parseInt(未知来源)
    java.lang.Integer.parseInt(未知来源)
    org.apache.jsp.insert_002duser_jsp._jspService(insert_002duser_jsp.java:122)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:443)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
  
  注意根本原因的完整堆栈跟踪在服务器中可用
  日志。
  
  Apache Tomcat / 9.0.0.M21

最佳答案

Integer group = (request.getParameter("group") != null) ? Integer.parseInt(request.getParameter("group")) : null;




<select name="group" id="group">

09-10 09:46
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