Clever use of jquery and servlets for cross-domain requests

It's interesting to see a lot of jquery cross-domain request articles on the Web. Here I publish a servlet and jquery configuration to implement the cross-domain code for everyone's reference. Please advise me of the shortcomings

Principle: JavaScript Ajax cannot cross domains, but it can be done across domains by making a request to a local servlet. The remote structure is then returned to the client. This way, Ajax can be cross-domain. In the back, send a PHP version, please pay attention to AH. Here is the code

JS Code:

Note: In post mode, param1 and param2 can have more than one parameter value sent to the remote.

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//GET方式function reqeustCrossDomainProxyGet(){    var url = "http://www.baidu.com";//远程请求地址    var param = {‘requesturl‘:url,‘typedata‘:‘JSON‘};    var data = getCrossDomainProxyRemote(param,"json");}//Post方式function reqeustCrossDomainProxyPost(param1,param2){    var url = apiServer+"/api/lucene/query";    var param = {‘requesturl‘:url,‘typedata‘:‘JSON‘,‘param1‘:param1,‘param2‘:param2};    var data = getCrossDomainProxyRemote(param,"json");}

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/** * JS向本址的一个Servlet发送POST请求，所有关于远程请求的参数。 * 在此处参POST方式发送给Servlet * @param param 远程请求参数 * @param rtype JS返回类型（暂时没有用到） * @return */function getCrossDomainProxyRemote(param,rtype){    var url = "/cross/proxy";//Servlet的URL地址    var returndata;    $.ajax({        url: url,type: ‘POST‘,dataType: rtype,timeout: 40000,data:param, async:false,        error: function(response,error) {alert(response.status);},        success: function(data){returndata=data;}    });    return returndata;}

Java code:

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public class CorssDomainProxy extends HttpServlet {        public void doGet(HttpServletRequest req, HttpServletResponse resp)            throws ServletException, IOException {        this.doPost(req, resp);         }        public void doPost(HttpServletRequest req, HttpServletResponse resp)            throws ServletException, IOException {        boolean requestType = false;//标记远程请求类型，默认为GET方式        PrintWriter out = resp.getWriter();        Enumeration keys = req.getParameterNames();//取出客户端传入的所有参数名        ArrayList<String> params = new ArrayList<String>();        String url=null;        while (keys.hasMoreElements()){            String key = (String) keys.nextElement();            /**             * 如果请求参数内有如下几种表示，这此参数不参与远程请求             */            if(key.equals("requesturl")){//判断参数是否是，远程请求地址                url = req.getParameter(key);            }else if(key.equals("typedata")){//判断请求数据类型，暂时没有用到                            }else if(key.equals("returntype")){//判断请求返回类型，暂时没有用到                            }else{                params.add(key);//其它加入参数列表，此处为参与远程请求的参数                requestType = true;//修改标记，表求远程请求为POST方式            }        }                HttpClient client = new HttpClient();        HttpMethod method = null;        if(requestType){//判断请求方式，并实例化HttpMethod对象，true:POST,false:GET            method = new UTF8PostMethod(url);            for(String name : params){//迭代POST参数，加入到请求中                String _value = req.getParameter(name);                ((PostMethod)method).setParameter(name,_value);            }        }else{            method = new GetMethod(url);        }               client.executeMethod(method);//执行请求        String bodystr = method.getResponseBodyAsString();//返回结果        out.println(bodystr);//将结果返回给客户端    }        /**     * 内部类，转换URL字符串为UTF-8     * @author Administrator     *     */    private static class UTF8PostMethod extends PostMethod {         public UTF8PostMethod(String url) {             super(url);         }         @Override        public String getRequestCharSet() {             return "UTF-8";         }     }    }

Clever use of jquery and servlets for cross-domain requests