ajax案例

注册表单之校验用户名是否注册

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>用户名是否被注册</title>
<script type="text/javascript">
//创建异步对象
function createXMLHttpRequest() {
    try {
        return new XMLHttpRequest();//大多数浏览器
    } catch (e) {
        try {
            return ActvieXObject("Msxml2.XMLHTTP");//IE6.0
        } catch (e) {
            try {
                return ActvieObject("Microsoft.XMLHTTP");//IE5.5及更早
            } catch (e) {
                alert("你的浏览器暂不能支持此功能！");
                throw e;
            }
        }
    }
}
window.onload = function(){
    //获取文本框，给他们的失去焦点事件注册监听
    var userEle = document.getElementById("usernameEle");
    userEle.onblur = function(){
        //得到异步对象
        var xmlHttp = createXMLHttpRequest();
        //打开连接
        xmlHttp.open("POST","<c:url value='/ValidateUsernameServlet'/>",true);
        //设置请求头：Conten-Type
        xmlHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
        //发送请求，给出请求体
        xmlHttp.send("username="+userEle.value);
        //给xmlHttp的onreadystatechange事件注册监听
        xmlHttp.onreadystatechange = function(){
            if(xmlHttp.readyState == 4 && xmlHttp.status == 200){
                //获取服务器的响应
                var text = xmlHttp.responseText;
                if(text == "1"){
                    //得到span元素
                    var span = document.getElementById("errorSpan");
                    span.innerText = "用户名已被注册！";
                }
            }
        };
    };
};
</script>
</head>
<body>
    <h1>演示用户是否被注册</h1>
    <form action="<c:url value='/ValidateUsernameServlet'/> " method="post">
    用户名：<input type="text" name="username" id="usernameEle"><span id="errorSpan"></span><br>
    密　码：<input type="text" name="password"><br>
    <input type="submit" value="注册">
    </form>
</body>
</html>
ajax3.jsp
package cn.cmlx.web.servlet;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/ValidateUsernameServlet")
public class ValidateUsernameServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");
        /*
         * 1.获取参数username
         * 2.判断是否为cmlx：如果是就响应1，如果不是就响应0
         */
        String username = request.getParameter("username");
        if(username.equals("cmlx")) {
            response.getWriter().print("1");
        }else {
            response.getWriter().print("0");
            
        }
    }

}
ValidateUsernameServlet.java

响应内容为xml

 

 省市联动

 代码：

china.xml

<?xml version="1.0" encoding="UTF-8"?>
<china>
    <province name="北京">
        <city>东城</city>
        <city>西城</city>
        <city>崇文</city>
        <city>宣武</city>
        <city>朝阳</city>
        <city>丰台</city>
        <city>石景山</city>
        <city>海淀</city>
        <city>门头沟</city>
        <city>房山</city>
        <city>通州</city>
        <city>顺义</city>
        <city>昌平</city>
        <city>大兴</city>
        <city>平谷</city>
        <city>怀柔</city>
        <city>密云</city>
        <city>延庆</city>
    </province>
    <province name="上海">
        <city>黄浦</city>
        <city>卢湾</city>
        <city>徐汇</city>
        <city>长宁</city>
        <city>静安</city>
        <city>普陀</city>
        <city>闸北</city>
        <city>虹口</city>
        <city>杨浦</city>
        <city>闵行</city>
        <city>宝山</city>
        <city>嘉定</city>
        <city>浦东</city>
        <city>金山</city>
        <city>松江</city>
        <city>青浦</city>
        <city>南汇</city>
        <city>奉贤</city>
        <city>崇明</city>
    </province>
    <province name="天津">
        <city>和平</city>
        <city>东丽</city>
        <city>河东</city>
        <city>西青</city>
        <city>河西</city>
        <city>津南</city>
        <city>南开</city>
        <city>北辰</city>
        <city>河北</city>
        <city>武清</city>
        <city>红挢</city>
        <city>塘沽</city>
        <city>汉沽</city>
        <city>大港</city>
        <city>宁河</city>
        <city>静海</city>
        <city>宝坻</city>
        <city>蓟县</city>
    </province>
    <province name="重庆">
        <city>万州</city>
        <city>涪陵</city>
        <city>渝中</city>
        <city>大渡口</city>
        <city>江北</city>
        <city>沙坪坝</city>
        <city>九龙坡</city>
        <city>南岸</city>
        <city>北碚</city>
        <city>万盛</city>
        <city>双挢</city>
        <city>渝北</city>
        <city>巴南</city>
        <city>黔江</city>
        <city>长寿</city>
        <city>綦江</city>
        <city>潼南</city>
        <city>铜梁</city>
        <city>大足</city>
        <city>荣昌</city>
        <city>壁山</city>
        <city>梁平</city>
        <city>城口</city>
        <city>丰都</city>
        <city>垫江</city>
        <city>武隆</city>
        <city>忠县</city>
        <city>开县</city>
        <city>云阳</city>
        <city>奉节</city>
        <city>巫山</city>
        <city>巫溪</city>
        <city>石柱</city>
        <city>秀山</city>
        <city>酉阳</city>
        <city>彭水</city>
        <city>江津</city>
        <city>合川</city>
        <city>永川</city>
        <city>南川</city>
    </province>
    <province name="河北">
        <city>石家庄</city>
        <city>邯郸</city>
        <city>邢台</city>
        <city>保定</city>
        <city>张家口</city>
        <city>承德</city>
        <city>廊坊</city>
        <city>唐山</city>
        <city>秦皇岛</city>
        <city>沧州</city>
        <city>衡水</city>
    </province>
    <province name="山西">
        <city>太原</city>
        <city>大同</city>
        <city>阳泉</city>
        <city>长治</city>
        <city>晋城</city>
        <city>朔州</city>
        <city>吕梁</city>
        <city>忻州</city>
        <city>晋中</city>
        <city>临汾</city>
        <city>运城</city>
    </province>
    <province name="内蒙古">
        <city>呼和浩特</city>
        <city>包头</city>
        <city>乌海</city>
        <city>赤峰</city>
        <city>呼伦贝尔盟</city>
        <city>阿拉善盟</city>
        <city>哲里木盟</city>
        <city>兴安盟</city>
        <city>乌兰察布盟</city>
        <city>锡林郭勒盟</city>
        <city>巴彦淖尔盟</city>
        <city>鄂市</city>
    </province>
    <province name="辽宁">
        <city>沈阳</city>
        <city>大连</city>
        <city>鞍山</city>
        <city>抚顺</city>
        <city>本溪</city>
        <city>丹东</city>
        <city>锦州</city>
        <city>营口</city>
        <city>阜新</city>
        <city>辽阳</city>
        <city>盘锦</city>
        <city>铁岭</city>
        <city>朝阳</city>
        <city>葫芦岛</city>
    </province>
    <province name="吉利">
        <city>长春</city>
        <city>吉林</city>
        <city>四平</city>
        <city>辽源</city>
        <city>通化</city>
        <city>白山</city>
        <city>松原</city>
        <city>白城</city>
        <city>延边</city>
    </province>
    <province name="黑龙江">
        <city>哈尔滨</city>
        <city>齐齐哈尔</city>
        <city>牡丹江</city>
        <city>佳木斯</city>
        <city>大庆</city>
        <city>绥化</city>
        <city>鹤岗</city>
        <city>鸡西</city>
        <city>黑河</city>
        <city>双鸭山</city>
        <city>伊春</city>
        <city>七台河</city>
        <city>大兴安岭</city>
    </province>
    <province name="江苏">
        <city>南京</city>
        <city>镇江</city>
        <city>苏州</city>
        <city>南通</city>
        <city>扬州</city>
        <city>盐城</city>
        <city>徐州</city>
        <city>连云港</city>
        <city>常州</city>
        <city>无锡</city>
        <city>宿迁</city>
        <city>泰州</city>
        <city>淮安</city>
    </province>
    <province name="浙江">
        <city>杭州</city>
        <city>宁波</city>
        <city>温州</city>
        <city>嘉兴</city>
        <city>湖州</city>
        <city>绍兴</city>
        <city>金华</city>
        <city>衢州</city>
        <city>舟山</city>
        <city>台州</city>
        <city>丽水</city>
    </province>
    <province name="安徽">
        <city>合肥</city>
        <city>芜湖</city>
        <city>蚌埠</city>
        <city>马鞍山</city>
        <city>淮北</city>
        <city>铜陵</city>
        <city>安庆</city>
        <city>黄山</city>
        <city>滁州</city>
        <city>宿州</city>
        <city>池州</city>
        <city>淮南</city>
        <city>巢湖</city>
        <city>阜阳</city>
        <city>六安</city>
        <city>宣城</city>
        <city>亳州</city>
    </province>
    <province name="福建">
        <city>福州</city>
        <city>厦门</city>
        <city>莆田</city>
        <city>三明</city>
        <city>泉州</city>
        <city>漳州</city>
        <city>南平</city>
        <city>龙岩</city>
        <city>宁德</city>
    </province>
    <province name="江西">
        <city>南昌市</city>
        <city>景德镇</city>
        <city>九江</city>
        <city>鹰潭</city>
        <city>萍乡</city>
        <city>新馀</city>
        <city>赣州</city>
        <city>吉安</city>
        <city>宜春</city>
        <city>抚州</city>
        <city>上饶</city>
    </province>
    <province name="山东">
        <city>济南</city>
        <city>青岛</city>
        <city>淄博</city>
        <city>枣庄</city>
        <city>东营</city>
        <city>烟台</city>
        <city>潍坊</city>
        <city>济宁</city>
        <city>泰安</city>
        <city>威海</city>
        <city>日照</city>
        <city>莱芜</city>
        <city>临沂</city>
        <city>德州</city>
        <city>聊城</city>
        <city>滨州</city>
        <city>菏泽</city>
    </province>
    <province name="河南">
        <city>郑州</city>
        <city>开封</city>
        <city>洛阳</city>
        <city>平顶山</city>
        <city>安阳</city>
        <city>鹤壁</city>
        <city>新乡</city>
        <city>焦作</city>
        <city>濮阳</city>
        <city>许昌</city>
        <city>漯河</city>
        <city>三门峡</city>
        <city>南阳</city>
        <city>商丘</city>
        <city>信阳</city>
        <city>周口</city>
        <city>驻马店</city>
        <city>济源</city>
    </province>
    <province name="湖北">
        <city>武汉</city>
        <city>鄂州</city>
        <city>宜昌</city>
        <city>荆州</city>
        <city>襄樊</city>
        <city>黄石</city>
        <city>荆门</city>
        <city>黄冈</city>
        <city>十堰</city>
        <city>恩施</city>
        <city>潜江</city>
        <city>天门</city>
        <city>仙桃</city>
        <city>随州</city>
        <city>咸宁</city>
        <city>孝感</city>
    </province>
    <province name="湖南">
        <city>长沙</city>
        <city>常德</city>
        <city>株洲</city>
        <city>湘潭</city>
        <city>衡阳</city>
        <city>岳阳</city>
        <city>邵阳</city>
        <city>益阳</city>
        <city>娄底</city>
        <city>怀化</city>
        <city>郴州</city>
        <city>永州</city>
        <city>湘西</city>
        <city>张家界</city>
    </province>
    <province name="广东">
        <city>广州</city>
        <city>深圳</city>
        <city>珠海</city>
        <city>汕头</city>
        <city>东莞</city>
        <city>中山</city>
        <city>佛山</city>
        <city>韶关</city>
        <city>江门</city>
        <city>湛江</city>
        <city>茂名</city>
        <city>肇庆</city>
        <city>惠州</city>
        <city>梅州</city>
        <city>汕尾</city>
        <city>河源</city>
        <city>阳江</city>
        <city>清远</city>
        <city>潮州</city>
        <city>揭阳</city>
        <city>云浮</city>
    </province>
    <province name="广西">
        <city>南宁</city>
        <city>柳州</city>
        <city>桂林</city>
        <city>梧州</city>
        <city>北海</city>
        <city>防城港</city>
        <city>钦州</city>
        <city>贵港</city>
        <city>玉林</city>
        <city>南宁地区</city>
        <city>柳州地区</city>
        <city>贺州</city>
        <city>百色</city>
        <city>河池</city>
    </province>
    <province name="海南">
        <city>海口</city>
        <city>三亚</city>
    </province>
    <province name="四川">
        <city>成都</city>
        <city>绵阳</city>
        <city>德阳</city>
        <city>自贡</city>
        <city>攀枝花</city>
        <city>广元</city>
        <city>内江</city>
        <city>乐山</city>
        <city>南充</city>
        <city>宜宾</city>
        <city>广安</city>
        <city>达川</city>
        <city>雅安</city>
        <city>眉山</city>
        <city>甘孜</city>
        <city>凉山</city>
        <city>泸州</city>
    </province>
    <province name="贵州">
        <city>贵阳</city>
        <city>六盘水</city>
        <city>遵义</city>
        <city>安顺</city>
        <city>铜仁</city>
        <city>黔西南</city>
        <city>毕节</city>
        <city>黔东南</city>
        <city>黔南</city>
    </province>
    <province name="云南">
        <city>昆明</city>
        <city>大理</city>
        <city>曲靖</city>
        <city>玉溪</city>
        <city>昭通</city>
        <city>楚雄</city>
        <city>红河</city>
        <city>文山</city>
        <city>思茅</city>
        <city>西双版纳</city>
        <city>保山</city>
        <city>德宏</city>
        <city>丽江</city>
        <city>怒江</city>
        <city>迪庆</city>
        <city>临沧</city>
    </province>
    <province name="西藏">
        <city>拉萨</city>
        <city>日喀则</city>
        <city>山南</city>
        <city>林芝</city>
        <city>昌都</city>
        <city>阿里</city>
        <city>那曲</city>
    </province>
    <province name="陕西">
        <city>西安</city>
        <city>宝鸡</city>
        <city>咸阳</city>
        <city>铜川</city>
        <city>渭南</city>
        <city>延安</city>
        <city>榆林</city>
        <city>汉中</city>
        <city>安康</city>
        <city>商洛</city>
    </province>
    <province name="甘肃">
        <city>兰州</city>
        <city>嘉峪关</city>
        <city>金昌</city>
        <city>白银</city>
        <city>天水</city>
        <city>酒泉</city>
        <city>张掖</city>
        <city>武威</city>
        <city>定西</city>
        <city>陇南</city>
        <city>平凉</city>
        <city>庆阳</city>
        <city>临夏</city>
        <city>甘南</city>
    </province>
    <province name="宁夏">
        <city>银川</city>
        <city>石嘴山</city>
        <city>吴忠</city>
        <city>固原</city>
    </province>
    <province name="青海">
        <city>西宁</city>
        <city>海东</city>
        <city>海南</city>
        <city>海北</city>
        <city>黄南</city>
        <city>玉树</city>
        <city>果洛</city>
        <city>海西</city>
    </province>
    <province name="新疆">
        <city>乌鲁木齐</city>
        <city>石河子</city>
        <city>克拉玛依</city>
        <city>伊犁</city>
        <city>巴音郭勒</city>
        <city>昌吉</city>
        <city>克孜勒苏柯尔克孜</city>
        <city>博尔塔拉</city>
        <city>吐鲁番</city>
        <city>哈密</city>
        <city>喀什</city>
        <city>和田</city>
        <city>阿克苏</city>
    </province>
    <province name="香港">
        <city>香港</city>
    </province>
    <province name="澳门">
        <city>澳门</city>
    </province>
    <province name="台湾">
        <city>台北</city>
        <city>高雄</city>
        <city>台中</city>
        <city>台南</city>
        <city>屏东</city>
        <city>南投</city>
        <city>云林</city>
        <city>新竹</city>
        <city>彰化</city>
        <city>苗栗</city>
        <city>嘉义</city>
        <city>花莲</city>
        <city>桃园</city>
        <city>宜兰</city>
        <city>基隆</city>
        <city>台东</city>
        <city>金门</city>
        <city>马祖</city>
        <city>澎湖</city>
    </province>
    <province name="其他">
        <city>北美洲</city>
        <city>南美洲</city>
        <city>亚洲</city>
        <city>非洲</city>
        <city>欧洲</city>
        <city>大洋洲</city>
    </province>
</china>
china.xml

Ajax5.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>省市联动</title>
<script type="text/javascript">
    /*
     *1.在文档加载完毕时发送请求，得到所有省份名称，显示在<select name="province">中
     *2.在选择了新的省份时，发送请求（参数为省名称），得到xml、文档，即<province>元素
     解析xml文档，得到其中所有的<city>，在得到每个<city>元素的内容，即市名，使用市名生成<option>，插入到<select name="city">元素中
     */
    //创建异步对象
    function createXMLHttpRequest() {
        try {
            return new XMLHttpRequest();//大多数浏览器
        } catch (e) {
            try {
                return ActvieXObject("Msxml2.XMLHTTP");//IE6.0
            } catch (e) {
                try {
                    return ActvieObject("Microsoft.XMLHTTP");//IE5.5及更早
                } catch (e) {
                    alert("你的浏览器暂不能支持此功能！");
                    throw e;
                }
            }
        }
    }
    window.onload = function() {
        /*ajax四步,qingqiuProvinceServlet，得到所有省份的名称
        使用每个省份的名称创建一个<option>元素，添加到<select name="province">中
         */
        var xmlHttp = createXMLHttpRequest();
        xmlHttp.open("GET", "<c:url value='/ProvinceServlet'/>",true);
        xmlHttp.send(null);
        xmlHttp.onreadystatechange = function(){
            if(xmlHttp.readyState == 4 && xmlHttp.status == 200){
                //获取服务器的响应
                var text = xmlHttp.responseText;
                //使用逗号分隔它，得到数组
                var arr = text.split(",");
                //循环遍历每个省份的名称，每个名称生成一个option对象，添加到select中
                for(var i=0;i<arr.length;i++){
                    var op = document.createElement("option");//创建一个指名名称元素
                    op.value = arr[i];//设置op的实际值为当前的省份名称
                    var textNode = document.createTextNode(arr[i]);//创建文本节点
                    op.appendChild(textNode);//把文本子节点添加到op元素中，指定其显示值
                    document.getElementById("p").appendChild(op);
                }
            }
        };
        /*
        第二件事：给<select name="province">添加改变监听
        使用选择的省份名称请求CityServlet，得到<province>元素(xml元素)！！！
        获取<province元素所有的<city>元素，遍历之！获取每个<city>的文本内容，即市名称
        使用每个市名称创建<optiong>元素，添加到<select name="city">
        */
        var proSelect = document.getElementById("p");
        proSelect.onchange = function(){
            var xmlHttp = createXMLHttpRequest();
            xmlHttp.open("POST","<c:url value='/CityServlet'/>",true);
            xmlHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
            xmlHttp.send("pname="+proSelect.value);//把下拉列表中选择的值发送给服务器！
            xmlHttp.onreadystatechange = function(){
                if(xmlHttp.readyState ==4 && xmlHttp.status == 200){
                    /*
                    把select中的所有option移除(除了请选择)
                    */
                    var citySelect = document.getElementById("c");
                    //获取其所有子元素
                    var optionEleList = citySelect.getElementsByTagName("option");
                    //循环遍历每个option元素，然后在citySelect中移除
                    while(optionEleList.length > 1){//子元素的个数如果大于1就循环，等于1就不循环了！
                        citySelect.removeChild(optionEleList[1]);//总是删除1下标，因为1删除了2就变成1了
                    }
                    var doc = xmlHttp.responseXML;
                    //得到所有名为city的元素
                    var cityEleList = doc.getElementsByTagName("city");
                    for(var i=0;i<cityEleList.length;i++){
                        var cityEle    = cityEleList[i];//得到每个city元素
                    //获取市名称
                        var cityName;
                        if(window.addEventListener){//处理浏览器差异
                            cityName = cityEle.textContent;//支持其他浏览器
                        }else{
                            cityName = cityEle.text;//支持IE
                        }
                        //使用市名称创建option元素,添加到<select name="city">中
                        var op = document.createElement("option");
                        op.value = cityName;
                        //创建文本节点
                        var textNode = document.createTextNode(cityName);
                        op.appendChild(textNode);//把文本节点追加到op元素中
                        //把op添加到<select>元素中
                        citySelect.appendChild(op);
                    }
                }
            };
            
        };
    };
</script>
</head>
<body>
    <h1>省市联动</h1>
    <select name="province" id="p">
        <option>===请选择省===</option>
    </select>

    <select name="city" id="c">
        <option>===请选择市===</option>
    </select>
</body>
</html>
Ajax.jsp

ProvinceServlet.java

package cn.cmlx.web.servlet;

import java.io.IOException;
import java.io.InputStream;
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.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.io.SAXReader;


@WebServlet("/ProvinceServlet")
public class ProvinceServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");
        /*
         * 响应所有省份名称，使用逗号隔开！
         */
        /*
         * 1.document对象 *创建解析器对象 *调用解析器的读方法，传递一个流对象，得到document
         */
        try {
            SAXReader reader = new SAXReader();
            InputStream input = this.getClass().getResourceAsStream("/china.xml");
            Document doc = reader.read(input);
            /*
             * 查询所有的province的name属性，得到一堆的属性对象 循环遍历，把所有的属性值连成一个字符串，发送给客户端
             */
            List<Attribute> arrList = doc.selectNodes("//province/@name");// Xpath查找
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < arrList.size(); i++) {
                sb.append(arrList.get(i).getValue());
                if (i < arrList.size() - 1) {
                    sb.append(",");
                }
            }
            response.getWriter().print(sb);
        } catch (DocumentException e) {
            throw new RuntimeException(e);
        }
    }

}
ProvinceServlet.java

CityServlet.java

package cn.cmlx.web.servlet;

import java.io.IOException;
import java.io.InputStream;

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.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

@WebServlet("/CityServlet")
public class CityServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        response.setContentType("text/xml;charset=utf-8");
        /*
         * 获取省份名称，加载该省市的<province>元素 把元素转换成字符串发送给客户端
         */
        /*
         * 1.获取省份名称 2.使用省份名称查找到对应的<province>元素 3.把<province>元素转换成字符串，发送
         */
        try {
            // 创建SAXReader解析器对象
            SAXReader reader = new SAXReader();
            InputStream input = this.getClass().getResourceAsStream("/china.xml");
            // 调用解析器读方法
            Document doc = reader.read(input);
            /*
             * 获取参数
             */
            String pname = request.getParameter("pname");// 获取省份名称
            Element proEle = (Element) doc.selectSingleNode("//province[@name='" + pname + "']");
            String xmlStr = proEle.asXML();// 把元素转换成字符串 
            response.getWriter().print(xmlStr);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}
CityServlet

 

posted @ 2018-09-06 11:52  cmlx  阅读(163)  评论(0)    收藏  举报