JQuery + ajax + jsonp cross-origin access, jqueryjsonp
Jsonp (JSON with Padding) is a "usage mode" in json format that allows webpages to obtain information from other domains.
For more information about Jsonp, see http://baike.baidu.com/view/4101174.htm. The following is an example:
I. Client
Html code
- <! DOCTYPE html PUBLIC "-// W3C // dtd html 4.01 Transitional // EN" "http://www.w3.org/TR/html4/loose.dtd">
- <Html>
- <Head>
- <Meta http-equiv = "Content-Type" content = "text/html; charset = UTF-8">
- <Title> Insert title here </title>
- <Script type = "text/javascript" src = "resource/js/jquery-1.7.2.js"> </script>
- </Head>
- <Script type = "text/javascript">
- $ (Function (){
- /*
- // Abbreviated form, with the same effect
- $. GetJSON ("http://app.example.com/base/json.do? Sid = 1494 & busiId = 101 & jsonpCallback =? ",
- Function (data ){
- $ ("# Showcontent"). text ("Result:" + data. result)
- });
- */
- $. Ajax ({
- Type: "get ",
- Async: false,
- Url: "http://app.example.com/base/json.do? Sid = 1494 & busiId = 101 ",
- DataType: "jsonp", // the data type is jsonp
- Jsonp: "jsonpCallback", // parameters of the function name used by the server to receive callback calls
- Success: function (data ){
- $ ("# Showcontent"). text ("Result:" + data. result)
- },
- Error: function (){
- Alert ('fail ');
- }
- });
- });
- </Script>
- <Body>
- <Div id = "showcontent"> Result: </div>
- </Body>
- </Html>
Ii. Server Side
Java code
- Import java. io. IOException;
- Import java. io. PrintWriter;
- Import java. util. HashMap;
- Import java. util. Map;
- Import javax. servlet. http. HttpServletRequest;
- Import javax. servlet. http. HttpServletResponse;
- Import net. sf. json. JSONObject;
- Import org. springframework. stereotype. Controller;
- Import org. springframework. web. bind. annotation. RequestMapping;
- @ Controller
- Public class ExchangeJsonController {
- @ RequestMapping ("/base/json. do ")
- Public void exchangeJson (HttpServletRequest request, HttpServletResponse response ){
- Try {
- Response. setContentType ("text/plain ");
- Response. setHeader ("Pragma", "No-cache ");
- Response. setHeader ("Cache-Control", "no-cache ");
- Response. setDateHeader ("Expires", 0 );
- Map <String, String> map = new HashMap <String, String> ();
- Map. put ("result", "content ");
- PrintWriter out = response. getWriter ();
- JSONObject resultJSON = JSONObject. fromObject (map); // assemble json as needed
- String jsonpCallback = request. getParameter ("jsonpCallback"); // client request parameters
- Out. println (jsonpCallback + "(" + resultJSON. toString () + ")"); // return jsonp format data
- Out. flush ();
- Out. close ();
- } Catch (IOException e ){
- E. printStackTrace ();
- }
- }
- }
