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pengju/AjaxServlet.java

Created July 24, 2012 09:56
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Ajax技术实现省市级联的例子,其中servlet页面可以直接用service方法处理，减少代码量
Raw
AjaxServlet.java
package com.kaishengit.web;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.google.gson.Gson;
public class AjaxServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Map<String, List<String>> province = new HashMap<String, List<String>>();
List<String> hnList = new ArrayList<String>();
hnList.add("郑州");
hnList.add("新乡");
hnList.add("焦作");
hnList.add("开封");
List<String> sxList = new ArrayList<String>();
sxList.add("西安");
sxList.add("宝鸡");
sxList.add("渭南");
sxList.add("汉中");
List<String> gdList = new ArrayList<String>();
gdList.add("广州");
gdList.add("珠海");
gdList.add("深圳");
province.put("hn", hnList);
province.put("sx", sxList);
province.put("gd", gdList);
String name = request.getParameter("name");
List<String> citys = province.get(name);
response.setContentType("text/json;charset=utf-8");
Gson gson = new Gson();
String json = gson.toJson(citys);
PrintWriter out = response.getWriter();
out.print(json);
out.flush();
out.close();
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Map<String, List<String>> province = new HashMap<String, List<String>>();
List<String> hnList = new ArrayList<String>();
hnList.add("郑州");
hnList.add("新乡");
hnList.add("焦作");
hnList.add("开封");
List<String> sxList = new ArrayList<String>();
sxList.add("西安");
sxList.add("宝鸡");
sxList.add("渭南");
sxList.add("汉中");
List<String> gdList = new ArrayList<String>();
gdList.add("广州");
gdList.add("珠海");
gdList.add("深圳");
province.put("hn", hnList);
province.put("sx", sxList);
province.put("gd", gdList);
String name = request.getParameter("name");
List<String> citys = province.get(name);
response.setContentType("text/json;charset=utf-8");
Gson gson = new Gson();
String json = gson.toJson(citys);
PrintWriter out = response.getWriter();
out.print(json);
out.flush();
out.close();
}
}
Raw
index.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP 'index.jsp' starting page</title>
<script type="text/javascript" src="js/json.js"></script>
</head>
<body>
<select id="province">
<option value="">-- 请选择省份 --</option>
<option value="hn">河南</option>
<option value="sx">陕西</option>
<option value="gd">广东</option>
</select>
<select id="city">
<option value="">-- 请选择城市 --</option>
</select>
<script type="text/javascript">
var xmlHttp ;
function createXmlHttp() {
if(window.ActiveXObject) {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}else {
xmlHttp = new XMLHttpRequest();
}
}
document.getElementById("province").onchange = function() {
createXmlHttp();
var name = document.getElementById("province").value;
if(name != "") {
xmlHttp.open("post", "ajax.jspx", true);
xmlHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded" );
xmlHttp.onreadystatechange = callback;
xmlHttp.send("name=" + name);
};
};
function callback() {
if(xmlHttp.readyState == 4) {
if(xmlHttp.status == 200) {
var json = JSON.parse(xmlHttp.responseText);
document.getElementById("city").options.length = 1;
for(var i=0; i < json.length; i++) {
var city = json[i];
var option = new Option(city,city);
document.getElementById("city").options.add(option);
};
}else {
alert("Ajax Error : " + xmlHttp.status);
};
}else {
};
};
</script>
</body>
</html>
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