insertForm.jsp 파일에서 실행 후 추가 하면 insertPro.jsp 파일로 action을 통해 가진다음에
 insertPro.jsp파일에서 response.sendRedirect("list.jsp?id="+id); 을 통해 list.jsp로 가지게 되어있는 구조인데 무엇때문인지 자꾸 insertForm에서 추가를 하면 문제가 추가되지 않았다고만 뜹니다... 꼭 좀 부탁드려요!

 insertForm.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<meta name="viewport" content="width=device-width,initial-scale=1.0"/>
<link rel="stylesheet" href="style.css"/>

<form name="input" method="post" action="insertPro.jsp">
   <table width=600 border=1 bordercolor="black">
    <tr>
      <td class="label"><label for="question">문제</label>
      <td class="content"><input id="question" name="question" type="text" size="100"
          maxlength="50"  autofocus required></td></tr>
    <tr>
      <td align='center'>보기</td><td align='center'>내용</td></tr>
    <tr>
      <td class="label"><label for="ex1">1</label>
      <td class="content"><input id="ex1" name="ex1" type="text"
          size="100"  maxlength="50" required></td></tr>
    <tr>
      <td class="label"><label for="ex2">2</label>
      <td class="content"><input id="ex2" name="ex2" type="text"
          size="100"  maxlength="50" required></td></tr>
    <tr>
      <td class="label"><label for="ex3">3</label>
      <td class="content"><input id="ex3" name="ex3" type="text"
          size="100"  maxlength="50" required></td></tr>
    <tr>
      <td class="label"><label for="ex4">4</label>
      <td class="content"><input id="ex4" name="ex4" type="text"
          size="100"  maxlength="50" required></td></tr>
    <tr>
      <td class="label"><label for="dap">정답</label>
      <td class="content"><input id="dap" name="dap" type="text"
          size="100"  maxlength="50" required></td></tr>
   
    <tr>
      <td align='center' class="label2" colspan="2"><input type="submit" value="출제하기">
         <input type="reset" value="다시작성"></td></tr>
  </table>
</form>

insertPro.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ page import="java.sql.*"%>

<% request.setCharacterEncoding("utf-8");%>

<%
   String id = request.getParameter("id");
   String question= request.getParameter("question");
   String ex1 = request.getParameter("ex1");
   String ex2 = request.getParameter("ex2");
   String ex3 = request.getParameter("ex3");
   String ex4 = request.getParameter("ex4");
   String dap = request.getParameter("dap");
   Timestamp reg_date=new Timestamp(System.currentTimeMillis());

   Connection conn=null;
   PreparedStatement pstmt=null;
   String str="";

   try{
   String jdbcUrl="jdbc:mysql://localhost:3306/jsptest?useUnicode=true&characterEncoding=UTF-8";
     String dbId="jspid";
     String dbPass="jsppass";
  
   Class.forName("com.mysql.jdbc.Driver");
   conn=DriverManager.getConnection(jdbcUrl,dbId ,dbPass);
 
   String sql= "insert into member values (?,?,?,?,?,?,?,?)";
     pstmt=conn.prepareStatement(sql);
     pstmt.setString(1,id);
     pstmt.setString(2,question);   
     pstmt.setString(3,ex1);
     pstmt.setString(4,ex2);
     pstmt.setString(5,ex3);
     pstmt.setString(6,ex4);
     pstmt.setString(7,dap);
     pstmt.setTimestamp(8,reg_date);
     pstmt.executeUpdate();
  
     response.sendRedirect("list.jsp?id="+id);
 
  }catch(Exception e){
   e.printStackTrace();
   out.println("문제가 제대로 출제되지 않았습니다.");
  }finally{
   if(pstmt != null)
    try{pstmt.close();}catch(SQLException sqle){}
   if(conn != null)
    try{conn.close();}catch(SQLException sqle){}
  }
 %>

list.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ page import="java.sql.*"%>
<meta name="viewport" content="width=device-width,initial-scale=1.0"/>
<link rel="stylesheet" href="style.css"/>

<td><a href="insertForm.jsp?id">퀴즈출제</a></td>    
<table border=1 cellspacing=0 cellpadding=4>
  <tr  class="label">
   <td>번호</td>
   <td>제목</td>
   <td>출제일시</td>
   <td>삭제</td>
  
  </tr>
<%

 
  Connection conn=null;
  PreparedStatement pstmt=null;
  ResultSet rs=null;             
 
  try{
  String jdbcUrl="jdbc:mysql://localhost:3306/jsptest?useUnicode=true&characterEncoding=UTF-8";
     String dbId="jspid";
     String dbPass="jsppass";
 
  Class.forName("com.mysql.jdbc.Driver");
  conn=DriverManager.getConnection(jdbcUrl,dbId ,dbPass );

  String sql= "select * from id";
  pstmt=conn.prepareStatement(sql);
  rs=pstmt.executeQuery();

  while(rs.next()){
    String id= rs.getString("id");
    String question= rs.getString("question");
       Timestamp reg_date=rs.getTimestamp("reg_date");
      
    
%>
       <tr>
        <td><%=id%></td>
        <td><%=question%></td>
        <td><%=reg_date.toString()%></td>
        <td><a href="deletePro.jsp?id=<%=id%>">삭제</a></td>       
      </tr>
<%  }
  }catch(Exception e){
  e.printStackTrace();
  }finally{
  if(rs != null)
     try{rs.close();}catch(SQLException sqle){}
  if(pstmt != null)
  try{pstmt.close();}catch(SQLException sqle){}
  if(conn != null)
  try{conn.close();}catch(SQLException sqle){}
  }
%>
</table>