Jsonp(JSON with Padding)是资料格式 json 的一种“使用模式”，可以让网页从别的网域获取资料。
关于Jsonp更详细的资料请参考，下面给出例子：
一.客户端
- <!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(){
- /*
- //简写形式，效果相同
- $.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",//数据类型为jsonp
- jsonp: "jsonpCallback",//服务端用于接收callback调用的function名的参数
- success : function(data){
- $("#showcontent").text("Result:"+data.result)
- },
- error:function(){
- alert('fail');
- }
- });
- });
- </script>
- <body>
- <div id="showcontent">Result:</div>
- </body>
- </html>
二.服务器端
- 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); //根据需要拼装json
- String jsonpCallback = request.getParameter("jsonpCallback");//客户端请求参数
- out.println(jsonpCallback+"("+resultJSON.toString(1,1)+")");//返回jsonp格式数据
- out.flush();
- out.close();
- } catch (IOException e) {
- e.printStackTrace();
- }
- }
- }