HTML:
<%@page import="com.mysql.jdbc.Connection"%> <%@ page language="java" import="java.util.*,com.ajax.connection.ConnectionUtil" pageEncoding="UTF-8"%> <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%> <c:set var="ctx" value="${pageContext.request.contextPath}"/> <!DOCTYPE HTML> <html> <head> <title>ajax-省市区级联</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <style type="text/css"> *{padding:0px;margin:0px} body{font-family: "微软雅黑";font-size:14px;} fieldset{padding:80px; 485px;margin: 100px auto;border-radius:8px;} #province,#city,#area{padding:6px;120px;} </style> <script type="text/javascript" src="../js/jquery-1.11.1.min.js"></script> </head> <body> <% List<HashMap<String,Object>> maps = ConnectionUtil.findProvinces(); pageContext.setAttribute("provinces", maps); %> <fieldset> <legend>省市区三级联动</legend> 省份: <select id="province" onchange="select_citys(this)"> <option value="">-请选择-</option> <!-- 循环显示所有省份 --> <c:forEach var="pv" items="${provinces}"> <option value="${pv.id}">${pv.name}</option> </c:forEach> </select> 城市: <select id="city" onchange="select_areas(this)"> <option value="">-请选择-</option> </select> 区域: <select id="area"> <option value="">-请选择-</option> </select> </fieldset> <script type="text/javascript"> //通过省份ID查询查询所有的城市信息 function select_citys(obj){ var provinceId = $(obj).val(); if(!provinceId)return; // 声明变量就要判断是否为null $.ajax({ type:"post",//请求方式get/post url:"${ctx}/CityServlet",//请求对应的地址 data:{"provinceId":provinceId},//往服务器传递的参数， success:function(data){//服务器交互成功调用的回调函数，data就是服务器端传递出来的数据 var jdata = data.trim(); // 去前后空格 if(jdata=="fail"){ alert("查询失败!"); }else{ var jsonData = eval(jdata);//将字符串的json对象转换成json $("#area").html("<option>-请选择-</option>"); append_template(jsonData,"city"); } } }); }; //通过省份ID查询查询所有的城市信息 function select_areas(obj){ var cityId = $(obj).val(); if(!cityId)return; $.ajax({ type:"post", url:"${ctx}/AreaServlet", data:{"cityId":cityId}, success:function(data){ var jdata = data.trim(); if(jdata=="fail"){ alert("查询失败!"); }else{ var jsonData = eval(jdata); append_template(jsonData,"area"); } } }); }; //封装其通用内容 function append_template(jsonData,target){ var length = jsonData.length; var html = "<option>-请选择-</option>"; for(var i=0;i<length;i++){ html +="<option value='"+jsonData[i].id+"'>"+jsonData[i].name+"</option>"; } $("#"+target).html(html); }; </script> </body> </html>
过滤器：
package com.ajax.filter; import java.io.IOException; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class CharacterFilter implements Filter { private FilterConfig config; public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException { HttpServletRequest request = (HttpServletRequest) req; HttpServletResponse response = (HttpServletResponse) resp; String encoding = config.getInitParameter("encoding"); if (encoding != null) { response.setContentType("text/html ;charset=" + encoding); request.setCharacterEncoding(encoding); response.setCharacterEncoding(encoding); } chain.doFilter(request, response); } public void init(FilterConfig config) throws ServletException { this.config = config; } public void destroy() { } }
web.xml:
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0"> <display-name>ajaxDemo</display-name> <!-- 字符编码集拦截器 --> <filter> <filter-name>CharacterFilter</filter-name> <filter-class>com.ajax.filter.CharacterFilter</filter-class> <!-- 配置初始化参数 --> <init-param> <param-name>encoding</param-name> <param-value>UTF-8</param-value> </init-param> </filter> <!-- 映射路径 --> <filter-mapping> <filter-name>CharacterFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <welcome-file-list> <welcome-file>pages/province.jsp</welcome-file> </welcome-file-list> </web-app>
控制层代码：
package com.ajax.dao; import java.io.IOException; import java.io.PrintWriter; import java.util.HashMap; import java.util.List; 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 org.apache.struts2.json.JSONException; import org.apache.struts2.json.JSONUtil; import com.ajax.connection.ConnectionUtil; @WebServlet("/AreaServlet") public class AreaServlet extends HttpServlet { private static final long serialVersionUID = 1L; protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { PrintWriter out=response.getWriter(); String cid = request.getParameter("cityId"); if (cid != null && !cid.equals("")) { int cityId = Integer.parseInt(cid); List<HashMap<String, Object>> areas = ConnectionUtil .findAreas(cityId); try { out.print(JSONUtil.serialize(areas)); } catch (JSONException e) { e.printStackTrace(); } } else { out.print("fail"); } } }
package com.ajax.dao; import java.io.IOException; import java.io.PrintWriter; import java.util.HashMap; import java.util.List; 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 org.apache.struts2.json.JSONException; import org.apache.struts2.json.JSONUtil; import com.ajax.connection.ConnectionUtil; @WebServlet("/CityServlet") public class CityServlet extends HttpServlet { private static final long serialVersionUID = 1L; protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { PrintWriter out=response.getWriter(); String pid = request.getParameter("provinceId"); if (pid != null && !pid.equals("")) { int provinceId = Integer.parseInt(pid); List<HashMap<String, Object>> citys = ConnectionUtil .findCitys(provinceId); try { out.print(JSONUtil.serialize(citys)); } catch (JSONException e) { e.printStackTrace(); } } else { out.print("fail"); } } }
持久层代码：
package com.ajax.connection; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.ArrayList; import java.util.HashMap; import java.util.List; public class ConnectionUtil { private static String url = "jdbc:mysql://localhost:3306/estore"; private static String username = "root"; private static String password = "f111111"; public static Connection getConnection(){ Connection connection = null; try{ Class.forName("com.mysql.jdbc.Driver"); connection = DriverManager.getConnection(url,username,password); return connection; }catch(Exception ex){ return null; } } public static List<HashMap<String, Object>> findProvinces(){ Connection connection = null; Statement statement = null; ResultSet rs = null; List<HashMap<String, Object>> maps = null; try{ String sql = "SELECT id,province FROM tm_province order by sort asc"; connection = getConnection(); statement = connection.createStatement(); rs = statement.executeQuery(sql); maps = new ArrayList<HashMap<String,Object>>(); HashMap<String, Object> map = null; while(rs.next()){ map = new HashMap<String, Object>(); map.put("id", rs.getInt("id")); map.put("name", rs.getString("province")); maps.add(map); } return maps; }catch(SQLException sql){ sql.printStackTrace(); return null; }finally{ try{ if(rs!=null)rs.close(); if(statement!=null)statement.close(); if(connection!=null)connection.close(); }catch(SQLException sql){ sql.printStackTrace(); } } } public static List<HashMap<String, Object>> findCitys(int provinceId){ Connection connection = null; PreparedStatement statement = null; ResultSet rs = null; List<HashMap<String, Object>> maps = null; try{ String sql = "SELECT id,city FROM tm_city WHERE province_id = ?"; connection = getConnection(); statement = connection.prepareStatement(sql); statement.setInt(1, provinceId); rs = statement.executeQuery(); maps = new ArrayList<HashMap<String,Object>>(); HashMap<String, Object> map = null; while(rs.next()){ map = new HashMap<String, Object>(); map.put("id", rs.getInt("id")); map.put("name", rs.getString("city")); maps.add(map); } return maps; }catch(SQLException sql){ sql.printStackTrace(); return null; }finally{ try{ if(rs!=null)rs.close(); if(statement!=null)statement.close(); if(connection!=null)connection.close(); }catch(SQLException sql){ sql.printStackTrace(); } } } public static List<HashMap<String, Object>> findAreas(int cityId){ Connection connection = null; PreparedStatement statement = null; ResultSet rs = null; List<HashMap<String, Object>> maps = null; try{ String sql = "SELECT id,area FROM tm_area WHERE city_id = ?"; connection = getConnection(); statement = connection.prepareStatement(sql); statement.setInt(1, cityId); rs = statement.executeQuery(); maps = new ArrayList<HashMap<String,Object>>(); HashMap<String, Object> map = null; while(rs.next()){ map = new HashMap<String, Object>(); map.put("id", rs.getInt("id")); map.put("name", rs.getString("area")); maps.add(map); } return maps; }catch(SQLException sql){ sql.printStackTrace(); return null; }finally{ try{ if(rs!=null)rs.close(); if(statement!=null)statement.close(); if(connection!=null)connection.close(); }catch(SQLException sql){ sql.printStackTrace(); } } } }
