准备：
- 在src下导入c3p0-config.xml
- 导入JDBCUtil
- 创建数据库
- 新建js文件夹导入jQuery配置文件
NO01:创建city.jsp页面
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script type="text/javascript" src="js/jquery-1.11.3.min.js"></script>
<!-- <script type="text/javascript" src="js/city_json.js"></script> -->
<script type="text/javascript" src="js/city_xml.js"></script>
</head>
<body>
省份: <select name="province" id ="province">
<option value="" >-请选择 -
<option value="1" >广东
<option value="2" >湖南
<option value="3" >湖北
<option value="4" >四川
</select>
城市:
<select name="city" id="city">
<option value="" >-请选择 -
</select>
</body>
</html>
NO02:在js下创建city_xml.js
$(function() {
//1.找到省份的元素
$("#province").change(function() {
//2. 一旦里面的值发生了改变，那么就去请求该省份的城市数据
var pid = $(this).val();
/*<list>
<city>
<id>1<id>
<pid>1</pid>
<cname>深圳</cname>
</city>
<city >
<id>2<id>
<pid>1</pid>
<cname>东莞</cname>
</city>
</list>*/
$.post( "CityServlet_XML",{pid:pid} ,function(data,status){
//先清空以前的值：
$("#city").html("<option value='' >-请选择-")
//遍历：
//从data数据里面找出所有的city ， 然后遍历所有的city。
//遍历一个city，就执行一次function方法
$(data).find("city").each(function() {
//遍历出来的每一个city，取它的孩子。 id , cname
var id = $(this).children("id").text();
var cname = $(this).children("cname").text();
$("#city").append("<option value='"+id+"' >"+cname)
});
} );
});
});
NO03:在js下创建city_json.js
$(function() {
//1.找到省份的元素
$("#province").change(function() {
//2. 一旦里面的值发生了改变，那么就去请求该省份的城市数据
//$("#province").varl();
var pid = $(this).val();
/*[
{
"cname": "深圳",
"id": 1,
"pid": 1
},
{
"cname": "东莞",
"id": 2,
"pid": 1
}
...
]*/
$.post( "CityServlet_json",{pid:pid} ,function(data,status){
//先清空
$("#city").html("<option value='' >-请选择-");
//再遍历，追加
$(data).each(function(index , c) {
$("#city").append("<option value='"+c.id+"' >"+c.cname)
});
},"json" );
});
});
NO04:创建XML方法的servlet
public class CityServlet_XML extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
try {
//1. 获取参数
int pid = Integer.parseInt(request.getParameter("pid"));
//2 找出所有的城市
CityDao dao = new CityDaoImpl();
List<CityBean> list = dao.findCity(pid);
//3. 返回数据。手动拼 --- XStream 转化 bean对象成 xml
XStream xStream = new XStream();
//想把id做成属性
//xStream.useAttributeFor(CityBean.class, "id");
//设置别名
xStream.alias("city", CityBean.class);
//转化一个对象成xml字符串
String xml = xStream.toXML(list);
//返回数据
response.setContentType("text/xml;charset=utf-8");
response.getWriter().write(xml);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
};
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
NO05:创建json方法的servlet
public class CityServlet_json extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
try {
//1. 获取参数
int pid = Integer.parseInt(request.getParameter("pid"));
//2 找出所有的城市
CityDao dao = new CityDaoImpl();
List<CityBean> list = dao.findCity(pid);
//3. 把list ---> json数据
//JSONArray ---> 变成数组 ， 集合 []
//JSONObject ---> 变成简单的数据 { name : zhangsan , age:18}
JSONArray jsonArray = JSONArray.fromObject(list);
String json = jsonArray.toString();
response.setContentType("text/html;charset=utf-8");
response.getWriter().write(json);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
};
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
NO06:创建bean
package com.rick.domain;
public class CityBean {
private int id;
private int pid ;
private String cname;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public int getPid() {
return pid;
}
public void setPid(int pid) {
this.pid = pid;
}
public String getCname() {
return cname;
}
public void setCname(String cname) {
this.cname = cname;
}
}
NO07:创建Dao
public interface CityDao {
List<CityBean> findCity(int pid) throws SQLException ;
}
NO08:创建Dao的实现类
public class CityDaoImpl implements CityDao {
@Override
public List<CityBean> findCity(int pid) throws SQLException {
QueryRunner runner = new QueryRunner(JDBCUtil.getDataSouce());
String sql = "select * from city where pid = ?";
return runner.query(sql, new BeanListHandler<CityBean>(CityBean.class) , pid);
}
}
