JSONP跨域访问

1. Extra JS
   

   Import JQuery, JSON and JQuery-JSONP.
   

2. Client
   

   1)  access with JSONP
   

   function testJSONP(para1, para2) {
   	// generate a parameter JSON object
   	var para = [ {
   		'para1' : para1,
   		'para2' : para2
   	} ];
   	
   	var URL = "www.xxx.com/xxx";
   
   	$.ajax({
   		type : "get",
   		cache : false,
   		url : URL + "/method.do",
   		data : $.param(para[0]),
   		dataType : "jsonp",
   		jsonp : "callBackFun",
   		contentType : "application/x-javascript;charset=UTF-8",
   		success : function(data) {
   			// return article JSON list
   			alert("success");
   		},
   		error : function(data) {
   			// ERROR
   			alert("error");
   		}
   	});
   }

   2)  access with JQuery-JSONP
   

   function testJSONP(para1, para2) {
   	// generate a parameter JSON object
   	var para = [ {
   		'para1' : para1,
   		'para2' : para2
   	} ];
   	
   	var URL = "www.xxx.com/xxx";
   
   	$.jsonp({
   	    url: URL + "/method.do",
   	    data: $.param(para[0]),
   	    callbackParameter: "callBackFun",
   	    success: function (data) {
   	        alert("success");
   	    },
   	    error: function (xOptions, textStatus) {
   	    	alert("error");
   	    }
   	});
   }

3. Server
   

   public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception
   {
   	request.setCharacterEncoding("UTF-8");
   	
   	// result object
   	Object object = new Object();
   
   	// change object to JSON String
   	JSONObject jsonObject = JSONObject.fromObject(object);
   	String resultStr = jsonObject.toString();
   	
   	// Add callback function to JSON String
   	String callBackFun = request.getParameter("callBackFun");
   	if(callBackFun != null)
   		resultStr = callBackFun + "(" + resultStr + ")";
   	
   	// return JSON to Client
   	response.setHeader("Cache-Control", "no-cache");
   	response.setContentType("application/x-javascript;charset=UTF-8");
   	response.getWriter().print(resultStr);
   
   	return null;
   }