1.首先要导入jar文件：
c3p0-0.9.5.1.jar
commons-beanutils-1.7.0.jar
commons-collections-3.2.jar
commons-dbutils-1.6.jar
commons-lang-2.4.jar
commons-logging-1.0.4.jar
ezmorph-1.0.3.jar
fastjson-1.1.40.jar
jackson-all-1.7.5.jar
json-lib-2.2.3-jdk15.jar
mchange-commons-java-0.2.10.jar
mysql-connector-java-5.1.30-bin.jar
2.c3p0配置文件
1 <?xml version="1.0" encoding="UTF-8"?> 2 <c3p0-config> 3 <default-config> 4 5 <property name="checkoutTimeout">30000</property> 6 <property name="idleConnectionTestPeriod">30</property> 7 <property name="initialPoolSize">10</property> 8 <property name="maxIdleTime">30</property> 9 <property name="maxPoolSize">100</property> 10 <property name="minPoolSize">10</property> 11 <property name="maxStatements">200</property> 12 13 <!-- 驱动程序 --> 14 <property name="driverClass">com.mysql.jdbc.Driver</property> 15 <!-- 数据库连接url地址 --> 16 <property name="jdbcUrl">jdbc:mysql://localhost:3306/day02</property> 17 <!-- 用户名 --> 18 <property name="user">****</property> 19 <!-- 密码 --> 20 <property name="password">****</property> 21 22 23 </default-config> 24 </c3p0-config> 25 26 <!-- <?xml version="1.0" encoding="UTF-8"?> 27 <c3p0-config> 28 <named-config > 29 <property name="acquireIncrement">5</property> 30 <property name="initialPoolSize">3</property> 31 <property name="minPoolSize">1</property> 32 <property name="maxPoolSize">10</property> 33 <property name="maxStatements">0</property> 34 <property name="user">root</property> 35 <property name="password">root</property> 36 ?useUnicode=true&characterEncoding=UTF-8 37 <property name="jdbcUrl">jdbc:mysql://localhost:3306/test</property> 38 <property name="driverClass">com.mysql.jdbc.Driver</property> 39 </named-config> 40 </c3p0-config> --> 41 42 43
3..要建三张表，省市区分别一张
3.写对应的实体类
1 public class Province { 2 3 private Integer provinceId; 4 private String provinceName; 5 6 .....省略get和set代码 7 }
1 public class City { 2 3 private Integer cityId; 4 private String cityName; 5 6 .....省略get和set方法 7 }
1 public class Area { 2 3 private Integer areaId; 4 private String areaName; 5 ...省略set和get方法 6 }
4.Util包下的DBManager
1 public class DBManager { 2 3 private static ComboPooledDataSource cpds=new ComboPooledDataSource(); 4 5 //获取数据库资源 6 public static ComboPooledDataSource getDateResource(){ 7 return cpds; 8 } 9 10 //返回连接对象 11 public static Connection getConn() throws SQLException{ 12 return cpds.getConnection(); 13 } 14 15 //释放资源 16 public static void release(Connection conn){ 17 DbUtils.closeQuietly(conn); 18 } 19 20 21 }
5.dao层
1 public class BaseDao{ 2 3 private static final QueryRunner runner = new QueryRunner(); 4 5 public <T> List<T> getForList(String sql,Class<T> clazz,Object ...args) throws SQLException{ 6 7 List<T> list = null; 8 9 Connection conn = null; 10 11 try { 12 conn = DBManager.getConn(); 13 list = runner.query(conn, sql,new BeanListHandler<T>(clazz),args); 14 } catch (Exception e) { 15 throw new RuntimeException(e); 16 }finally{ 17 DbUtils.close(conn); 18 } 19 20 return list; 21 22 23 }
6.前台页面 index.jsp
<% response.sendRedirect("provinceServlet?method=listProvince"); %>
访问顺序是--->index.jsp----->provinceServlet?method=listProvince------>provice.jsp
7.provice.jsp(包含ajax代码)
1 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> 2 <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%> 3 4 5 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 6 <html> 7 <head> 8 9 10 <title>三级联动页面</title> 11 12 <meta http-equiv="pragma" content="no-cache"> 13 <meta http-equiv="cache-control" content="no-cache"> 14 <meta http-equiv="expires" content="0"> 15 <!-- 16 1.获取#province，添加change函数 17 2.使#province只保留一个option子节点 18 3.获取province下来菜单选择的值，若选择的值为“”（请选择省份），此时不需要发送ajax请求 19 4.若值不为“”，说明的确是province发生了改变，发送ajax请求 20 4.1 url：provinceServlet?method= 21 4.2 args: 22 5.返回的是一个json数组 23 6.遍历，创建<option value="provinceId">provinceName</option> 24 并把新创建的option节点加为#city的子节点 25 --> 26 <script type="text/javascript" src="js/jquery-2.1.4.js"></script> 27 <script type="text/javascript"> 28 $(function(){ 29 //第二级 30 $("#province").change(function(){ 31 32 $("#city option:not(:first)").remove(); 33 var province = $(this).val(); 34 //alert(province); 35 36 var url = "provinceServlet?method=listCity"; 37 var args = {"provinceId":province/* ,"time":new Date() */}; 38 39 $.getJSON(url, args, function(data){ 40 //alert("11111"); 41 42 for(var i = 0;i < data.length; i++){ 43 44 var cityId = data[i].cityId; 45 var cityName = data[i].cityName; 46 47 $("#city").append("<option value='"+ cityId + "'>"+cityName+"</option>") 48 49 } 50 51 52 53 }); 54 55 56 57 58 } 59 ); 60 61 62 //第三极 63 $("#city").change(function(){ 64 65 $("#area option:not(:first)").remove(); 66 var city = $(this).val(); 67 //alert(province); 68 69 var url = "provinceServlet?method=listArea"; 70 var args = {"cityId":city,"time":new Date()}; //这里写一个时间戳 每次点击时，时间戳都不一样，浏览器就认为是新的图片，然后就发送请求了。 71 72 $.getJSON(url, args, function(data){ 73 //alert("11111"); 74 75 for(var i = 0;i < data.length; i++){ 76 77 var areaId = data[i].areaId; 78 var areaName = data[i].areaName; 79 80 $("#area").append("<option value='"+ areaId + "'>"+areaName+"</option>") 81 82 } 83 84 85 86 }); 87 88 89 90 91 } 92 ); 93 }); 94 95 </script> 96 97 </head> 98 99 <body> 100 省份：<select id="province"> 101 <option>请选择省份</option> 102 <c:forEach items="${provinces}" var="province"> 103 <option value="${province.provinceId}">${province.provinceName}</option> 104 </c:forEach> 105 106 </select> 107 城市：<select id="city"> 108 <option>请选择城市</option> 109 </select> 110 区域：<select id="area"> 111 <option>请选择区域</option> 112 </select> 113 </body> 114 </html>
8.proviceServlet
1 package three.controller; 2 3 import java.io.IOException; 4 import java.lang.reflect.Method; 5 import java.sql.SQLException; 6 import java.util.List; 7 8 import javax.servlet.ServletException; 9 import javax.servlet.http.HttpServlet; 10 import javax.servlet.http.HttpServletRequest; 11 import javax.servlet.http.HttpServletResponse; 12 13 import org.codehaus.jackson.map.ObjectMapper; 14 15 import three.dao.BaseDao; 16 import three.domain.Area; 17 import three.domain.City; 18 import three.domain.Province; 19 20 public class provinceServlet extends HttpServlet { 21 22 23 public void doGet(HttpServletRequest request, HttpServletResponse response) 24 throws ServletException, IOException { 25 26 request.setCharacterEncoding("UTF-8"); 27 response.setContentType("text/html;charset=UTF-8"); 28 29 30 31 String methodName = request.getParameter("method"); 32 33 try { 34 Method method = getClass().getDeclaredMethod(methodName,HttpServletRequest.class,HttpServletResponse.class); 35 method.invoke(this, request,response); 36 } catch (Exception e) { 37 e.printStackTrace(); 38 } 39 40 } 41 42 private BaseDao baseDao = new BaseDao(); 43 public void listProvince(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException, SQLException{ 44 45 String sql = "SELECT provinceid,provincename FROM province;"; 46 List<Province> provinces = baseDao.getForList(sql, Province.class); 47 request.setAttribute("provinces", provinces); 48 49 request.getRequestDispatcher("/province.jsp").forward(request, response); 50 51 52 } 53 54 55 public void listCity(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException, SQLException{ 56 57 String provinceId = request.getParameter("provinceId"); 58 String sql = "select cityid,cityname from city c where c.cityid = ?"; 59 60 List<City> cities = baseDao.getForList(sql, City.class, Integer.parseInt(provinceId)); 61 62 System.out.println(cities+"==========="); 63 64 ObjectMapper mapper = new ObjectMapper(); 65 String result = mapper.writeValueAsString(cities); 66 System.out.println(result); 67 68 response.setContentType("text/javascript"); 69 response.getWriter().print(result); 70 71 72 } 73 74 public void listArea(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException, SQLException{ 75 76 String cityId = request.getParameter("cityId"); 77 String sql = "select areaid,areaname from area a where a.areaid = ?"; 78 79 List<Area> areas = baseDao.getForList(sql, Area.class, Integer.parseInt(cityId)); 80 81 System.out.println(areas+"==========="); 82 83 ObjectMapper mapper = new ObjectMapper(); 84 String result = mapper.writeValueAsString(areas); 85 System.out.println(result); 86 87 response.setContentType("text/javascript"); 88 response.getWriter().print(result); 89 90 91 } 92 93 public void doPost(HttpServletRequest request, HttpServletResponse response) 94 throws ServletException, IOException { 95 96 doGet(request,response); 97 } 98 99 }