问题:@Requestbody 用的时候遇到400和415错误，因为请求格式不对。

@RequestBody

@RequestBody能把简单json结构参数转换成实体类，如下代码：

@RequestMapping(value = "/testUser", method = RequestMethod.POST)    public String testUser(@RequestBody User user){        System.out.print(user.getAge()); return "success"; }

参数为：

{
     "id":1,"user":"pkxutao","name":"name","age":18}

注意请求的content type要设置为application/json

$.ajax({         type:"POST",         url : "adjectfkController/exportTemplate",         cache:false,         async:true,         dataType:"json",           contentType : 'application/json;charset=utf-8', //设置请求头信息           data:jsonstr,         success : function(result) {                console.log(result);            },        error : function(result) {                console.log("错误-----------------------------");            }    });

学习链接:https://blog.csdn.net/qq_27093465/article/details/50519444