Ajax二级联动

 1 <%--
 2   Created by IntelliJ IDEA.
 3   User: x1c
 4   Date: 2019-12-22
 5   Time: 10:04
 6   To change this template use File | Settings | File Templates.
 7 --%>
 8 <%@ page contentType="text/html;charset=UTF-8" language="java" %>
 9 
10   
11     
12     
43   
44   
45 
46   -请选择手机品牌-
47   华为
48   小米
49   oppo
50 
51   
52     -请选择机型-
53   
54   
55 

 

package com.bj;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

@WebServlet("/phoneServlet")
public class PhoneServlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String value = req.getParameter("val");
        List Phone = new ArrayList();
        if(value.equals("1")){
            Phone.add("HAWEIMATE9 PRO");
            Phone.add("HAWEIMATE10 PRO");
            Phone.add("HAWEIMATE20 PRO");
        } else if("2".equals(value)){
            Phone.add("小米4");
            Phone.add("小米8");
            Phone.add("小米2s");
        } else if("3".equals(value)){
            Phone.add("OPPOX");
            Phone.add("OPPOXx");
            Phone.add("OPPOXxx");
        }
        resp.setCharacterEncoding("UTF-8");
        resp.setContentType("text/html;charset=UTF-8");
        //集合的输处格式
        resp.getWriter().print(Phone.toString());
    }
}