我想在servlet中弹出一个窗口，如何写？

看这段这是调用javabean的<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<jsp:useBean id="Purview" scope="page" class="com.teach.Main.PurviewBean" />
<%String userloginname = session.getAttribute("UserLoginName")
.toString();
String usertype = session.getAttribute("UserType").toString();
Collection plist = Purview.getPurviewList(userloginname, usertype);
if (plist == null) {
plist = new ArrayList();
}
pageContext.setAttribute("purviewlist", plist);
%>

这是拿个bean
package com.teach.Main;
import com.teach.db.ContextWy;
import com.teach.db.DBCPool;
import java.util.Collection;
import java.util.ArrayList;
import java.sql.*;

//得到左侧权限列表框
public class PurviewBean {
private String strDbip;
private String strType;
private String strUse