JAVA處理外部連接的方法

js中直接同步、異步調用外部系統連接失效，或者無返回值等狀況的判斷與處理。

首先要用同步、異步幾種方式測試該連接是否有效，當無效後引入下面jsp代碼，該代碼文件是被調用文件：

<%@ page contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ page import="org.apache.commons.httpclient.*"%>
<%@ page import="org.apache.commons.httpclient.methods.GetMethod"%>
<%@ page import="java.io.*"%>
<%
 String getString = "";
 String httpurl = request.getParameter("getMailUrl");
 if(httpurl != null && !"".equals(httpurl)){
  httpurl = java.net.URLDecoder.decode(httpurl,"UTF-8");
  HttpClient httpclient = new HttpClient();
  HttpMethod method = null;
  method = new GetMethod(httpurl);
  try {
      httpclient.executeMethod(method);
      getString = method.getResponseBodyAsString();
  } catch (HttpException e) {
      e.printStackTrace();
  } catch (IOException e) {
      e.printStackTrace();
  }
 }
out.print(getString);
%>

2.這裏是個取外部郵件的例子，附上調用代碼文件

var url = 'http://10.2.10.4/cgi-bin/getnewnum?domain=*****.com&username=<%=accountMail[0]%>';
 var getMailUrl = "/defaultroot/public/jsp/ajax_******.jsp?getMailUrl="+encodeURIComponent(url);
 var dlzgMailCount = $.trim(com_ajax_ReqDo(getMailUrl));

//調用函數

function com_ajax_ReqDo(url){
 var redata='';
 $.ajaxSetup({ async : false });
    $.get(url,function(data){
        redata = data;
    });
 $.ajaxSetup({ async : true });
 return redata;
}