关于Ajax中处理回传参数的几种实现

来源：互联网发布：淘宝怎么卖酒编辑：程序博客网时间：2024/06/13 10:08

我的试验主要包括4种:
1.回传一个普通的String字符串.
2.回传一个组织好的Javascript字符串.
3.回传一个Json对象.(需要引入json.jar)
4.回传一个XML对象.
基本实现如下:
其中测试页面为:

     001<%@page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
002<%request.setCharacterEncoding("UTF-8");%>
003<html>
004<head>
005<title>测试Ajax页面</title>
006</head>
007<body>
008<table width="100%" height="100%" >
009    <td align="center" valign="center" >
010        <form action="" method="post" onsubmit="">
011            <table border="3" >
012                <tr>
013                    <td>
014                        <input name="试验返回String" type="button" value="试验返回String" onclick="testAjaxForString();" style="width:140px;">
015                    </td>
016                </tr>
017                <tr>
018                    <td>
019                        <input name="试验返回javascriptString" type="button" value="试验返回javascriptString" onclick="testAjaxForObject();" style="width:140px;">
020                    </td>
021                </tr>
022                <tr>
023                    <td>
024                        <input name="试验返回json" type="button" value="试验返回json" onclick="testAjaxForJson();" style="width:140px;">
025                    </td>
026                </tr>
027                <tr>
028                    <td>
029                        <input name="试验返回xml" type="button" value="试验返回xml" onclick="testAjaxForXml();" style="width:140px;">
030                    </td>
031                </tr>
032            </table>
033        </form>
034    </td>
035</table>
036</body>
037</html>
038 
039<script type="text/javascript">
040var xmlHttp ;
041function createXmlHttpRequest(){
042    if(window.ActiveXObject){
043        xmlHttp = new ActiveXObject("Microsoft.XMLHTTP") ;
044    }else if(window.XMLHttpRequest){
045        xmlHttp = new XMLHttpRequest();
046    }
047}
048/*返回String*/
049function testAjaxForString(){
050    createXmlHttpRequest();
051    var url = "HelloWorld?";
052    var queryString = "name=songwei";
053    url += queryString ;
054//    xmlHttp.onreadystatechange = parseHello ;//如果是异步,既open中最后一个参数为true.则打开该选项.
055    xmlHttp.open("post",url,false);
056    xmlHttp.send(null);
057    alert(xmlHttp.responseText); //如果是字符串或者xml.
058}
059 
060/*返回JsObject*/
061function testAjaxForObject(){
062    createXmlHttpRequest();
063    var url = "HelloWorldForObject?";
064    var queryString = "name=songwei";
065    url += queryString ;
066//    xmlHttp.onreadystatechange = parseHello ;
067    xmlHttp.open("post",url,false);
068    xmlHttp.send(null);
069    alert(xmlHttp.responseText);
070    var o = eval(xmlHttp.responseText);
071    alert("username="+o.username);
072    alert("password="+o.password);
073    var farray = o.friend ;
074    var fname ="";
075    for(var i=0;i<farray.length;i++){
076        fname += farray[i]+"    ";
077    }
078    alert("friend list ="+fname);    
079}
080//返回Json
081function testAjaxForJson(){
082    createXmlHttpRequest();
083    var url = "HelloWorldForJson?";
084    var queryString = "name=songwei";
085    url += queryString ;
086    xmlHttp.open("post",url,false);
087    xmlHttp.send(null);
088    alert(xmlHttp.responseText);
089    var o = eval("(" + xmlHttp.responseText + ")");
090    alert(o.userInfo.username);
091    alert(o.userInfo.password);
092    alert(o.userInfo.friends[0]);
093    alert(o.userInfo.friends[1]);
094}
095 
096//返回XML
097function testAjaxForXml(){
098    createXmlHttpRequest();
099    var url = "HelloWorldForXML?";
100    var queryString = "name=songwei";
101    url += queryString ;
102    xmlHttp.open("post",url,false);
103    xmlHttp.send(null);
104    alert(xmlHttp.responseXML);
105    alert ("tagName: " + xmlHttp.responseXML.documentElement.tagName);
106    var xmlDoc = xmlHttp.responseXML ;
107    var xmlRoot=xmlDoc.documentElement;
108 
109    var friendsItem=xmlRoot.getElementsByTagName("friends");
110    alert(friendsItem[0].firstChild.firstChild.data);
111    alert(friendsItem[0].firstChild.nextSibling.firstChild.data);
112    var usernameItem = xmlRoot.getElementsByTagName("username");
113    alert(usernameItem[0].firstChild.data);
114 
115}
116</script>

对于各种回传方式的不同servlet实现:
1.普通字符串 ,HelloWorld.java(Servlet)

     01 public class HelloWorld extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet {
02    public HelloWorld() {
03        super();
04    }       
05    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
06        doPost(request,response);
07    }      
08    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
09        // TODO Auto-generated method stub
10        String name = request.getParameter("name");
11        String str = "Hello "+name ;
12        PrintWriter pw = response.getWriter();
13        pw.print(str);
14        pw.close();
15    }                 
16}

2.Javascript字符串Servlet实现
HelloWorldForObject.java

     01 public class HelloWorldForObject extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet {
02    public HelloWorldForObject() {
03        super();
04    }       
05    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
06        doPost(request,response);
07    }      
08 
09    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
10        String name = request.getParameter("name");
11        User user = new User();
12        user.setUsername(name);
13        user.setPassword("abc");
14        List<String> friend = new ArrayList<String>();
15        friend.add("wangdong");
16        friend.add("zhaoyong");
17        user.setFriend(friend);
18        StringBuffer sb = new StringBuffer();
19        sb.append("var o = new Object();");
20        sb.append("o.username ='"+user.getUsername()+"' ;");
21        sb.append("o.password ='"+user.getPassword()+"' ;");
22        sb.append("o.friend = new Array(");
23        String tmp = "" ;
24        for(String s : user.getFriend()){
25            if(tmp.trim().length()<1){
26                tmp += "'"+s+"'" ;
27            }else{
28                tmp +="," ;
29                tmp += "'"+s+"'" ;
30            }
31        }
32        sb.append(tmp+") ;");
33        sb.append("o;");
34        PrintWriter pw = response.getWriter();
35        pw.print(sb.toString());
36        pw.close();
37    }                 
38}

3.JSon对象实现
HelloWorldForJson.java

     01public class HelloWorldForJson extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet {
02    public HelloWorldForJson() {
03        super();
04    }       
05    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
06        doPost(request,response);
07    }      
08    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
09         response.setCharacterEncoding("UTF-8");  
10         response.setHeader("Cache-Control","no-cache");  
11         request.setCharacterEncoding("UTF-8");          
12        String result = new String();
13        String name = request.getParameter("name");
14        try{
15            JSONObject jsonResult = new JSONObject();
16            jsonResult.put("username",name);
17            jsonResult.put("password","password");
18            JSONArray jsonFriends = new JSONArray();
19            jsonFriends.put("张三");
20            jsonFriends.put("李四");
21            jsonResult.put("friends",jsonFriends);
22            result = new JSONObject().put("userInfo", jsonResult).toString();
23        }catch(JSONException jex){
24            jex.printStackTrace();
25        }
26        response.getWriter().print(result);
27        response.getWriter().close();
28    }                 
29}

4.XML对象实现
HelloWorldForXML.java

     01 public class HelloWorldForXML extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet {
02    public HelloWorldForXML() {
03        super();
04    }       
05    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
06        doPost(request,response);
07    }      
08    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
09        String name = request.getParameter("name");
10        Document doc = null ;
11        String docStr ="" ;
12        try{
13            DocumentBuilderFactory dbf =DocumentBuilderFactory.newInstance();
14            DocumentBuilder db = dbf.newDocumentBuilder();
15            doc = db.newDocument();
16            Element root = doc.createElement("userInfo");
17            doc.appendChild(root);
18            Element nameE = doc.createElement("username");
19            Text nameT = doc.createTextNode(name);
20            nameE.appendChild(nameT);
21            root.appendChild(nameE);    
22 
23            Element passE = doc.createElement("password");
24            Text passT = doc.createTextNode("password");
25            passE.appendChild(passT);
26            root.appendChild(passE);    
27 
28            Element friends = doc.createElement("friends");
29 
30            Element friend1 = doc.createElement("friend");
31            Text f1T = doc.createTextNode("张三");
32            friend1.appendChild(f1T);
33            Element friend2 = doc.createElement("friend");
34            Text f2T = doc.createTextNode("李四");
35            friend2.appendChild(f2T);
36 
37            friends.appendChild(friend1);
38            friends.appendChild(friend2);
39            root.appendChild(friends);
40 
41            ByteArrayOutputStream bstream = null;
42            try {
43                bstream = new ByteArrayOutputStream();
44                Transformer xformer = TransformerFactory.newInstance()
45                        .newTransformer();
46                Source source = new DOMSource(doc);
47                Result result = new StreamResult(bstream);
48                xformer.transform(source, result);
49            } catch (Exception e) {
50                e.printStackTrace();
51            }        
52            try {
53                docStr =  new String(bstream.toByteArray(), "UTF-8");
54            } catch (UnsupportedEncodingException e) {
55                e.printStackTrace();
56                docStr = new String(bstream.toByteArray());
57            }
58            System.out.println(docStr);
59 
60        }catch(ParserConfigurationException ex){
61            ex.printStackTrace();
62        }
63        response.setContentType("text/xml;charset=UTF-8"); 
64        PrintWriter writer = response.getWriter();
65        writer.print(docStr); 
66        writer.flush(); 
67        writer.close();        
68    }

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