太久沒有研究過新技術(shù)了.作為一個(gè)程序員,我覺得很慚愧.老早就想看看關(guān)于xmlhttp的技術(shù)了,今天總算有點(diǎn)時(shí)間,做個(gè)一個(gè)最初的體驗(yàn).馬上就愛上了它.
如果你想不刷新頁面就可以與后臺(tái)進(jìn)行數(shù)據(jù)交互,或者在異構(gòu)系統(tǒng)之間交換數(shù)據(jù),xmlhttp技術(shù)是個(gè)不錯(cuò)的選擇.
下面是我的一個(gè)很小的體驗(yàn)程序,參考了csdn網(wǎng)友s_phoenix()給人的回貼.
首先建一個(gè)tomcat的web項(xiàng)目.
1:-------index.htm文件內(nèi)容如下:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<META NAME="Generator" CONTENT="EditPlus">
<META NAME="Author" CONTENT="">
<META NAME="Keywords" CONTENT="">
<META NAME="Description" CONTENT="">
</HEAD>
<BODY>
<script language="javascript">
var XML="<root><test>李春雷</test><test>毛澤東</test></root>"
var xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
var xmlDoc=new ActiveXObject("Msxml2.DOMDocument");
function test(){//客戶端xml的解析
xmlDoc.loadXML(XML);
if(xmlDoc.parseError.line>0){
throw xmlDoc.parseError.reason;
}
var nodes= xmlDoc.selectNodes("/root/test");
for(var i=0;i<nodes.length;i++){
alert(nodes.item(i).text);
}
}
function action(){//客戶端和服務(wù)端的通訊
xmlHttp.open("post","xmlHttp.send(XML);
var showstr=xmlHttp.responseText;
alert(showstr);
}
</script>
<button onclick="test();">查看將要傳輸?shù)膞ml</button><br/>
<button onclick="action();">朝服務(wù)器傳送xml,并接收服務(wù)器回應(yīng)</button>
</BODY>
</HTML>
2:------------寫一個(gè)servlet: UrlTestServlet.java
/*
* 創(chuàng)建日期 2005-4-7
*
* TODO 要更改此生成的文件的模板,請轉(zhuǎn)至
* 窗口 - 首選項(xiàng) - Java - 代碼樣式 - 代碼模板
*/
package com.lcl;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import org.dom4j.io.*;
import org.dom4j.*;
/**
* @author lcl
*
* TODO 要更改此生成的類型注釋的模板,請轉(zhuǎn)至
* 窗口 - 首選項(xiàng) - Java - 代碼樣式 - 代碼模板
*/
public class UrlTestServlet extends HttpServlet {
private static final String CONTENT_TYPE = "text/xml;charset=utf-8";
//Initialize global variables
public void init() throws ServletException {
}
//Process the HTTP Get request
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType(CONTENT_TYPE);
request.setCharacterEncoding("utf-8");
PrintWriter out = response.getWriter();
InputStream is=request.getInputStream();
SAXReader reader=new SAXReader();
Document doc=null;
try{
doc=reader.read(is);
} catch(Exception ex){
System.out.println(ex);
}
String[] s= getElementTexts(doc,"test");
out.println("數(shù)據(jù)交換成功:返回" + s[0] + s[1]);
}
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request,response);
}
private String getElementText(Document doc,String name){
return doc.getRootElement().element(name).getText();
}
private String[] getElementTexts(Document doc,String name){
List l=doc.getRootElement().elements(name);
Iterator it=l.iterator();
List l1=new LinkedList();
while(it.hasNext()){
Element e=(Element)it.next();
l1.add(e.getText());
}
return (String[])l1.toArray(new String[]{});
}
//Clean up resources
public void destroy() {
}
}
3:--------web.xml更改如下(加servlet映射):
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE web-app
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"
<web-app>
<display-name>Welcome to Tomcat</display-name>
<description>
Welcome to Tomcat
</description>
<!-- JSPC servlet mappings start -->
<servlet>
<servlet-name>UrlTestServlet</servlet-name>
<servlet-class>com.lcl.UrlTestServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>UrlTestServlet</servlet-name>
<url-pattern>/UrlTestServlet</url-pattern>
</servlet-mapping>
<!-- JSPC servlet mappings end -->
<welcome-file-list>
<welcome-file>index.htm</welcome-file>
</welcome-file-list>
</web-app>
好了,啟動(dòng)tomcat,訪問:http://127.0.0.1:8888/xmlhttpTest/work/(如果你的tomcat端口是8080,就改一下)
看到結(jié)果了吧,真的很不錯(cuò).不用刷新頁面,就讓htm前臺(tái)頁面和后臺(tái)進(jìn)行了一次數(shù)據(jù)交換.
你甚至可以在不同的服務(wù)器之間進(jìn)行數(shù)據(jù)交換,比如一個(gè)mis系統(tǒng),和一個(gè)gis系統(tǒng),想整合成一個(gè)系統(tǒng),原先我們是用了一個(gè)frame,左邊的是mis,右邊的是gis,通過javascript在兩個(gè)系統(tǒng)間交換數(shù)據(jù).如果用xmlhttp技術(shù),完全沒必要這樣了.
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