java 返回callback不同处理方法

package com.shopping.rest.controller;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.http.MediaType;import org.springframework.http.converter.json.MappingJacksonValue;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.ResponseBody;import com.shopping.common.utils.JsonUtils;import com.shopping.rest.pojo.CatResult;import com.shopping.rest.service.ItemCatService;/** * 商品展示列表 * @author zzg * */@Controllerpublic class ItemCatController {    @Autowired    private ItemCatService itemCatService;    @RequestMapping(value="/itemcat/list",            produces=MediaType.APPLICATION_JSON_VALUE+";charset=utf-8")    @ResponseBody    public String getItemCatList(String callback){        CatResult catResult = itemCatService.getItemCatList();        String json = JsonUtils.objectToJson(catResult);        String result = callback + "("+ json +")";        return result ;    }    /*此方法：同上    @RequestMapping("/itemcat/list")    @ResponseBody    public void getItemCatList(String callback,HttpServletResponse response) throws IOException{        CatResult catResult = itemCatService.getItemCatList();        String json = JsonUtils.objectToJson(catResult);        String result = callback + "("+ json +")";        response.setHeader("content-type", "text/html;charset=UTF-8");        response.getWriter().write(result);    }*/    /*此方法：同上；springmvc4.1之后的版本才可以    @RequestMapping("/itemcat/list")    @ResponseBody    public Object getItemCatList(String callback){        CatResult catResult = itemCatService.getItemCatList();        MappingJacksonValue jacksonValue = new MappingJacksonValue(catResult);        jacksonValue.setJsonpFunction(callback);        return jacksonValue;    }    */}