WEB怎么判断某一URL是否可用

2012-09-21

WEB如何判断某一URL是否可用最近客户进行网络改造，在改造过程中会有应用服务器的IP发生改变，且在一段时间

WEB如何判断某一URL是否可用

最近客户进行网络改造，在改造过程中会有应用服务器的IP发生改变，且在一段时间内各机构访问应用时地址会不同，有一些机构用192段的一个地址，有的用户就要用10段的一个地址，所以要在判断某一个请求时，一个URL不好使时，请求另一个URL，实验了几种方法。

1.使用JSP的方法,具体代码如下

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="java.net.URL" %>
<%@ page import="java.net.URLEncoder" %>
<%@ page import="java.net.MalformedURLException" %>
<%@ page import="java.net.URLConnection" %>
<%@ page import="java.net.HttpURLConnection" %>
<%@ page import="java.io.IOException" %>
<%

?????? try {
??????????
??????????? URL url = null;
??????????? url = new URL("http://localhost:8080/test/temp1.jsp"); //将此处换成要测试是否连通的地址??????
??????????? HttpURLConnection?? httpConnection?? =?? (HttpURLConnection)url.openConnection();
??????????? httpConnection.getURL();
??????????? int?? responseCode=httpConnection.getResponseCode();
??????????? System.out.println(responseCode);
??????????? if(responseCode==200) {//如果响应码为200说明此地址是通的，则跳到该地址，
?????????????? response.sendRedirect("http://localhost:8080/test/temp1.jsp");
??????????? }else{//否则跳到另外的地址
?????????????? response.sendRedirect("http://localhost:8080/test/temp2.jsp");
??????????? }?????????
??????? } catch (MalformedURLException e) {??????????
??????????? e.printStackTrace();? //To change body of catch statement use File | Settings | File Templates.
??????? } catch (IOException e) {
??????????? response.sendRedirect("http://localhost:8080/test/temp1.jsp");
??????????? e.printStackTrace();? //To change body of catch statement use File | Settings | File Templates.
??????? }
???
%>

2.使用javascript的方法

<%@ page contentType="text/html;charset=gb2312" language="java" %>
<html>
<script?? language="javascript">??
? function?? getURL(url)??
? {??
????????? var?? xmlhttp;
????????? if (window.ActiveXObject) {
??????????? xmlhttp?? = new?? ActiveXObject("Microsoft.XMLHTTP");??

?????????? }
????????? else if (window.XMLHttpRequest) {
????????? xmlhttp?? = new XMLHttpRequest();
????????? }??
????????? xmlhttp.open("GET",url,false);??
????????? xmlhttp.send();??
????????? if (xmlhttp.readyState==4)??
????????? {??
????????????? if(xmlhttp.Status!=200)
????????????? return false
????????????? else??
????????????? return true;
????????? }??
????????? return?? false;??
? }??
? function targetRrl(){
??? if(getURL("http://localhost:8080/test/temp1.jsp")==true)
??? {
????? window.location.href = "http://localhost:8080/test/temp1.jsp";

??? }
??? else{
???? window.location.href = "http://localhost:8080/test/temp2.jsp";
??? }
?? }

? </script>??

注：此种方法有跨域访问的问题，所以必须修改浏览器中internet选项->安全->其它->通过域访问数据源设为启动

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WEB怎么判断某一URL是否可用