关于ajax的跨域

这个问题是关于ajax跨域访问的

首先:本地file下js

var localPath="http://192.168.100.161:8080";


$(function(){
           var uuid="28293c941a3a322d9d9049a48a1045a2";
           var userCategoryType=3
           var c_url=localPath+"/api4/xclass/getTreeNode?uuid="+uuid+"&userCategoryType="+userCategoryType;
            
           //注意下面只需一个问号
           $.getJSON(c_url, function(data){  
                document.write(data) 
           });  
    
    })

然后服务器代码是

@RequestMapping(value="getTreeNode", method = RequestMethod.GET)
    @ResponseBody
    public Object getTreeNode(String uuid,Integer userCategoryType,HttpServletResponse response){
        User user=userService.getUserByMd5UserId(uuid);
        response.addHeader("Access-Control-Allow-Origin", "*");
        List<Map<String, Object>> userDocCategorys=mUserCategoryService.getUserDocCategorys(Long.parseLong(String.valueOf(user.getUserId())), userCategoryType);
        List<Map<String, Object>> ztreeNodes=new ArrayList<Map<String,Object>>();
        for (Map<String, Object> userCategory : userDocCategorys) {
            Map<String, Object> ztreeNodeMap = new HashMap<String, Object>();
            ztreeNodeMap = new HashMap<String, Object>();
            ztreeNodeMap.put("id",userCategory.get("user_category_id") );
            ztreeNodeMap.put("pId", userCategory.get("parent_id"));
            ztreeNodeMap.put("name", userCategory.get("user_category_name"));
            ztreeNodes.add(ztreeNodeMap);
        }
        return ztreeNodes;
    }

死活没法请求到,然后百度了下,发现是js的跨域,找了几个方法都不成功,包括jsonp等,最后
消息头中加入
  response.addHeader("Access-Control-Allow-Origin", "*");

  请求必须是$.getJSON()

很久没记笔记了,养成好习惯,加油