resultset next（）不执行

为什么resultset next（）不执行

<%@ page language="java" import="java.util.*" import="java.sql.*" contentType="text/html; charset=UTF-8"
         pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>查找结果</title>
</head>
<body>
<table align="center" border="1">
    <tr><th colspan="4">查找结果</th>
        <th colspan="1"><a href='select.jsp'>返回</a></th></tr>
    <tr><th>ID</th><th>菜名</th><th>价格</th><th>材料</th><th>食材</th><th>数量</th></tr>
    <%
        request.setCharacterEncoding("utf-8");
        Class.forName("com.mysql.cj.jdbc.Driver");
        Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/java_text?characterEncoding=utf-8","root","123456");
        Statement stmt=con.createStatement();
        String dishName=request.getParameter("dishName");
        String sql="select * from dish where dishName='" + dishName +"'";
        ResultSet rs=stmt.executeQuery(sql);
        int flag=0;

        while(rs.next()){
            flag=1;
            int dishID=rs.getInt(1);
            out.println("<tr><td>"+dishID+"</td><td>"+rs.getString(2)+"</td><td>"+rs.getString(3)+"</td><td>"+rs.getString(4)+"</td><td><a href='edit.jsp?id="+dishID+"'>修改</a>&nbsp;<a href='delete.jsp?id="+dishID+"'>删除</a></td></tr>");
        }
        if(flag==1){
            out.println("<script>alert('查找完成！');</script>");
        }else{
            out.println("<script>alert('没有找到！');</script>");
            response.setHeader("refresh", "1;url=select.jsp");
        }
        rs.close();
        stmt.close();
        con.close();
    %>
</table>
</body>
</html>

有可能是执行了，但是返回为false，也就是你的sql没有查到东西。所以没有走到循环。

如果没有查到信息，那下边内容就不执行

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