package com.model;
import com.dbutil.Dbconn;
import com.entity.City;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
/**
* Created by Ray on 2018/3/18 0018.
**/
public class CityDao {
Dbconn dbconn = new Dbconn();
Connection conn = null;
PreparedStatement ps;
ResultSet rs;
public List listAlias(String alias){
List citylist = new ArrayList();
City city = null;
try{
conn = dbconn.getConnection();
String sql = “select * from city where alias = ?”;
ps = conn.prepareStatement(sql);
ps.setString(1,alias);
rs = ps.executeQuery();
while (rs.next()){
city = new City();
city.setId(rs.getInt(“id”));
city.setName(rs.getString(“name”));
city.setAlias(rs.getString(“alias”));
citylist.add(city);
}
}catch (Exception e){
e.printStackTrace();
}
return citylist;
}
}
五、secondMenu.jsp
String path = request.getContextPath();
String basePath = request.getScheme() + “://” + request.getServerName() + “:” + request.getServerPort() + path + “/”;
%>
二级菜单联动
$(function () {
//给下拉列表添加事件
$(“#city1”).change(function () {
//测试
// alert($(this).val() + ” ” + $(“city1 option:selected”).text());
//post传输，固定四个参数
//第一个参数是url：发送请求地址
//第二个参数data：待发送的值key/value
//第三个参数callback：发送返回时回调函数
//第四个参数type：返回内容格式，常用text，json
$.post(“SecondMenu”, {city1: $(this).val()},
function (result) {
//获取第二级城市的id
var city2 = $(“#city2”);
//清空第二级里面的城市
city2.empty();
for (var i = 0; i < result.length; i++) {
city2.append(“” + result[i].name + “”);
}
}, “json”);
});
});
城市
请选择
广东
湖南
请选择
六、SecondMenu.javapackage com.control;
import com.entity.City;
import com.model.CityDao;
import net.sf.json.JSONArray;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
/**
* Created by Ray on 2018/3/18 0018.
**/
public class SecondMenu extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request,response);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//获取页面传输的数据
String alias = request.getParameter(“city1”);
System.out.println(“测试数据alias： ” + alias);
//调用模型
CityDao cityDao = new CityDao();
//将页面数据进行匹配，如果匹配成功显示下面创建的城市
List list = cityDao.listAlias(alias);
//将list转换为json
JSONArray jsonArray = JSONArray.fromObject(list);
//测试
System.out.println(jsonArray);
//响应页面
response.setCharacterEncoding(“utf-8”);
response.setContentType(“text/json”);
PrintWriter out = response.getWriter();
//打印json，为了页面获取
out.println(jsonArray);
out.flush();
out.close();
}
}
七、web.xml