Failed to load resource: the server responded with a status of 403 ()
personList.html:1 Failed to load http://192.168.0.103/person/getList: 
Response to preflight request doesn't pass access control check:
 No 'Access-Control-Allow-Origin' header is present on the requested resource. 
 Origin 'http://127.0.0.1:8020' is therefore not allowed access. The response had HTTP status code 403.

前后端联调时，出现如上的错误，可能是因为contentType指定不恰当或者后端要求数据格式不匹配引起的

1. 后端不要求json格式，但是前端是json格式

   前端：

   $(function(){
   	$.ajax({
   		type:"get",
   		url:"http://192.168.0.103/person/getList",
   		dataType:"json",
   		contentType:"application/json;charset=utf-8",
   		success:function(result){
   			alert(result);
   		}
   	});
   });
   

   后端：

   @RequestMapping(value = "/getList", produces = MediaType.APPLICATION_JSON_VALUE)
   @ResponseBody
   public ResultBean getList() {
   	return new ResultBean(getData());
   }
   

2. 后端要求是json，前端传的数据是form表单序列化$("#form").serialize()
   前端：

   $(function(){
   	$.ajax({
   		type:"post",
   		url:"http://192.168.0.103/person/createByJson",
   		dataType:"json",
   		data:$("#form").serialize(),
   		contentType:"application/json;charset=utf-8",
   		success:function(result){
   			alert(result);
   		}
   	});
   });
   

   后端：

   @PostMapping(value = "/createByJson", consumes = MediaType.APPLICATION_JSON_VALUE, produces = MediaType.APPLICATION_JSON_VALUE)
   @ResponseBody
   public ResultBean createByJson(@RequestBody @Validated Person person) {
   	return new ResultBean(person);
   }