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"> |
| 040 | var xmlHttp ; |
| 041 | function 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*/ |
| 049 | function 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*/ |
| 061 | function testAjaxForObject(){ |
| 062 | createXmlHttpRequest(); |
| 063 | var url = "HelloWorldForObject?"; |
| 064 | var queryString = "name=songwei"; |
| 065 | url += queryString ; |
| 066 | // xmlHttp.onreadystatechange = parseHello ; |
| 067 | xmlHttp.open("post",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 |
| 081 | function testAjaxForJson(){ |
| 082 | createXmlHttpRequest(); |
| 083 | var url = "HelloWorldForJson?"; |
| 084 | var queryString = "name=songwei"; |
| 085 | url += queryString ; |
| 086 | xmlHttp.open("post",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 |
| 097 | function testAjaxForXml(){ |
| 098 | createXmlHttpRequest(); |
| 099 | var url = "HelloWorldForXML?"; |
| 100 | var queryString = "name=songwei"; |
| 101 | url += queryString ; |
| 102 | xmlHttp.open("post",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,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,response); |
| 07 | } |
| 08 | |
| 09 | protected void doPost(HttpServletRequest request,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
| 01 | public class HelloWorldForJson extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet { |
| 02 | public HelloWorldForJson() { |
| 03 | super(); |
| 04 | } |
| 05 | protected void doGet(HttpServletRequest request,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,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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