跨域：一种通过服务端解决跨域的实现

有一种跨域的业务场景：
A域名页面，嵌套B域名页面，B域名页面又想访问A域名的数据，这时候就有跨域了，其中B域名页面请求的时候不会携带A域名要求的登录cookie信息

解决办法：B页面操作请求B域名，携带着B的cookie，然后有B的服务端来请求A获取数据

@RequestMapping("/proxy")
    @ResponseBody
    public String forwardSaveEOrder(HttpServletRequest request) {
        HttpClient qunarHttpClient = new DefaultHttpClient();
        qunarHttpClient.getParams().setParameter(ClientPNames.COOKIE_POLICY, CookiePolicy.BROWSER_COMPATIBILITY);

        HttpPost qunarHttpPost = new HttpPost(saveEOrderUrlForForwarding);
        
        qunarHttpPost.setHeader("Cookie", request.getHeader("Cookie"));
        List <NameValuePair> nvps = new ArrayList <NameValuePair>();   
        Enumeration<String> parameterNames = request.getParameterNames();
        while (parameterNames.hasMoreElements()) {
            String parameterName = parameterNames.nextElement();
            nvps.add(new BasicNameValuePair(parameterName, request.getParameter(parameterName)));  
        }
        try {
			qunarHttpPost.setEntity(new UrlEncodedFormEntity(nvps, HTTP.UTF_8));
		} catch (Exception e) {
			logger.error("",e);
		}
        
        try {
        	
            String result = EntityUtils.toString(qunarHttpClient.execute(qunarHttpPost).getEntity());
            return result;
        } catch (Exception e) {
            logger.error("error : while executing post, url : {}", saveEOrderUrlForForwarding,e);
            QMonitor.recordOne(forwardSaveEOrderExceptionMonitorKey);
            return "生单异常";
        } 

    }