• AJAX学习笔记


    <!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>Insert title here</title>
    <script type="text/javascript">
    window.onload = init;
    function init() {
    	//1、获取部门节点
    	var dn = document.getElementById("dep");
    	//2、为该节点创建onchange
    	dn.onchange = getPerson
    	//3、创建一个getPerson的方法来处理事件 
    }
    
    function getPerson() {
    	var did = this.value;
    	//1、获取XMLHttpRequest;
    	var xhr = createXMLHttpRequest();
    	//2、通过xhr来打开页面,使用POST
    	xhr.open("POST","person.do",true);
    	xhr.onreadystatechange = function() {
    		//3、处理请求
    		if(xhr.readyState==4&&xhr.status==200) {
    			//3.1、获取xml节点
    			var xmlDoc = xhr.responseXML;
    			//由于response的contentType是text/xml类型,此时就只能获取节点
    			//alert(xhr.resonseText);
    			//3.2、获取所有的person节点
    			var pns = xmlDoc.getElementsByTagName("person");
    			//3.3、遍历所以节点,获取id,name等信息
    			var node = "";
    			for(var i=0;i<pns.length;i++) {
    				node+=getValueByProp(pns[i],"id")+"----------"+
    				      getValueByProp(pns[i],"name")+"----------"+
    				      getValueByProp(pns[i],"salary")+"----------"+
    				      getValueByProp(pns[i],"age")+"<br/>"
    			}
    			//3.4、写入到persons
    			document.getElementById("persons").innerHTML = node;
    		}
    	}
    	xhr.setRequestHeader("Content-type","application/x-www-form-urlencoded");
    	xhr.send("did="+did);
    	//4、发送信息,需要传入did
    }
    //根据节点获取值
    function getValueByProp(node,prop) {
    	return (node.getElementsByTagName(prop))[0].firstChild.nodeValue;
    }
    
    function createXMLHttpRequest() {
    	if(window.XMLHttpRequest) {
    		//针对其他主流浏览器
    		return new XMLHttpRequest();
    	} else if(window.ActiveXObject) {
    		//针对IE5和IE6
    		return new ActiveXObject("Microsoft.XMLHTTP");
    	} else {
    		alert("你使用的浏览器不支持XMLHttpRequest,请换一个浏览器再试!");
    		return null;
    	}
    }
    </script>
    </head>
    <body>
    <select id="dep">
    	<option value="1">普通组</option>
    	<option value="2">会员组</option>
    	<option value="3">帅哥组</option>
    </select>
    <div id="persons"></div>
    </body>
    </html>

    JAVA代码:

    package com.study.servlet;

    import java.io.IOException;
    import java.io.Writer;

    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;

    import com.study.model.*;

    import java.util.*;
    /**
    * Servlet implementation class PersonServlet
    */
    public class PersonServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    Map<Integer,List<Person>> persons = new HashMap<Integer,List<Person>>();

    /**
    * @see HttpServlet#HttpServlet()
    */
    public PersonServlet() {
    super();
    List<Person> ps = new ArrayList<Person>();
    ps.add(new Person(1,"张三",1200,22));
    ps.add(new Person(2,"李四",1300,23));
    ps.add(new Person(3,"王五",1400,24));
    persons.put(1, ps);
    ps = new ArrayList<Person>();
    ps.add(new Person(11,"刘德华",12000,32));
    ps.add(new Person(12,"周杰伦",13000,33));
    ps.add(new Person(13,"张曼玉",14000,34));
    ps.add(new Person(14,"梁朝伟",15000,35));
    persons.put(2, ps);

    ps = new ArrayList<Person>();
    ps.add(new Person(21,"孙悟空",22000,132));
    ps.add(new Person(22,"猪八戒",23000,133));
    ps.add(new Person(23,"沙和尚",24000,134));
    ps.add(new Person(24,"唐和尚",25000,135));
    persons.put(3, ps);
    }

    /**
    * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
    */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub
    }

    /**
    * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
    */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    //1、由于返回的是xml,需要为respose设置contentType
    response.setContentType("text/xml;charset=utf-8");
    //2、获取Writer
    Writer out = response.getWriter();
    //3、获取部门id
    int did = Integer.parseInt(request.getParameter("did"));
    //4、获取用户列表对象,
    List<Person> ps = persons.get(did);
    //5、拼接xml
    StringBuffer px = new StringBuffer();
    px.append("<persons>");
    for(Person p:ps) {
    px.append("<person>");
    px.append("<id>").append(p.getId()).append("</id>");
    px.append("<name>").append(p.getName()).append("</name>");
    px.append("<salary>").append(p.getSalary()).append("</salary>");
    px.append("<age>").append(p.getAge()).append("</age>");
    px.append("</person>");
    }
    px.append("</persons>");
    out.write(px.toString());
    }

    }






      

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  • 原文地址:https://www.cnblogs.com/airycode/p/4827627.html
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