JSONP Super Simple example, a look can be started

JSON (JavaScript Object Notation) and Jsonp (JSON with Padding) have only one letter difference, but they're not the same thing at all: JSON is a data interchange format, And Jsonp is a kind of unofficial cross-domain data interaction protocol that is created by the ingenuity of the developers. JSONP solves the problem of Ajax cross-domain requests, and JSONP only resolves one of the cross-domain request scenarios.

The following is a simple introduction to the JSONP interface development process based on the servlet:

1, create a servlet interface Jsonpservlet

class  jsonpservlet  extends  httpservlet  {     Doget (HTTPSERVLETREQUEST REQ, HTTPSERVLETRESPONSE RESP)  servletexception, ioexception  {        //callback function name          String callback = req.getparameter ();         Resp.setcharacterencoding ();        jsonobject jo =  Jsonobject ();         jo.put (,);         system. println (Jo.tojsonstring ());         system. println (Jo.tostring ());         //wraps the JSON into the function name          resp.getwriter (). Print (Callback + + jo.tojsonstring ()  + );     }  &nBsp; dopost (HTTPSERVLETREQUEST REQ, HTTPSERVLETRESPONSE RESP)  ServletException,  Ioexception {        doget (REQ, RESP);     }}

2. Create an HTML file and call the Jsonp interface

& nbsp;               var  Localhandler = function (data) {             alert (' i am local fun,can be called by remote.js,remote js  return data : '  + data.result);        };         var url =  "http://localhost/jsonpServlet?callback= Localhandler ";        var script =  Document.createelement (' script ');         script.setattribute (' src '),  url);         document.getelementsbytagname (' head ') [0]. AppendChild (script);

After the call succeeds, the browser pops up the dialog box

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JSONP Super Simple example, a look can be started