Question

jsp中cannot be resolved

<form method="POST" action="login.jsp">
<%
//是否登陆
if((String)session.getValue("user_name")!=null)
{
String name=(String)session.getAttribute("user_name");
String sql="select * from member where user_name='"+name+"'";
//ResultSet rs=null;
rs=stmt.executeQuery(sql);
if(rs.next()){
%>
。。。。。。
所有的rs都有问题：

rs cannot be resolved to a variable
stmt cannot be resolved

若以下回答无法解决问题，邀请你更新回答

Answer 1

改成
<form method="POST" action="login.jsp">
<%
//是否登陆
String usr=(String)session.getValue("user_name");
if(usr!=null && !usr.equals(""))
{
String name=(String)session.getAttribute("user_name");
String sql="select * from member where user_name='"+name+"'";
//ResultSet rs=null;
rs=stmt.executeQuery(sql);
if(rs.next()){
%>