ajax跨域访问

前端js

$.ajax({
        url:"url",
        type:"post",
        dataType:"jsonp",
        jsonp:"jsoncallback",
        jsonpCallback:"successCallback",
        success:function(data){
            alert("成功")
        },
        error:function(){
            alert("失败")
        }
    })

后台代码jsonCallBack里面的函数名称一样

@Controller  
public class FromData {  
    @RequestMapping("/data.do")  
    public void getData1(HttpServletRequest req,HttpServletResponse rps){  
        System.out.println("1111111");  
        String str  = "Hello world";  
        JSONObject json = new JSONObject();  
        json.put("name", str);  
        try {  
            rps.getWriter().print("successCallback("+json.toJSONString()+")");  
        } catch (IOException e) {  
            // TODO Auto-generated catch block  
            e.printStackTrace();  
        }  
    }  
}