springmvc 415Unsupported Media Type

Question

我的ajax

    $('.submit').click(function(){
        var userName = $('.userName').val();
        var password = $('.password').val();
        var json={
            "userName":userName,
            "password":password
        };
        $.ajax({
            url:"/jsonTest.do",
            contentType:"application/json",
            dataType:"json",
            type:"POST",
            data:JSON.stringify(json),
            success:function (data) {
                console.log(data);
            },
            error:function (data) {
                alert("失败");
            }
            }
        )
    })

后台的controller

   @RequestMapping(value = "/jsonTest.do")
    public void jsonTest(@RequestBody User user,HttpServletRequest request,HttpServletResponse response) {
        System.out.println("jsonTest:userName" + user.getUserName());

        if (blogService.selectByPrimaryKey(1) == null) {
            addOneBlog(1);
        }
        BlogWithBLOBs blogWithBLOBs = blogService.selectByPrimaryKey(1);
       JsonUtil.toJSON(blogWithBLOBs,response);

    }

问题来了，我添加了@RequestBody标签就会报415Unsupported Media Type.当我把这个注解去掉后，就能正常取值了。为什么呢，我记得我学的时候都说的是用这个标签来接收json数据啊

Answer 1

JSON.stringify(json)就已经将你的json这个参数变成了对象,而@RequestBody接收的只是json对象的字符串,所以你用了JSON.stringify(json),就可以直接用对象接收,没加的话,用@RequestBody接收