RequestBody Ajax写法「建议收藏」

$.ajax({
                url : ‘', //传输地址
                type : "post",  //方式
                data: JSON.stringify({"newpassword":$("#paww").val()}),//newpassword为AppCodeApiParam里一参数名
                contentType: "application/json;charset=UTF-8",
                success : function(data) { //data为返回值
                    alert(data)
                    $("#paww").val(data)
                }
            })

@PostMapping(value = "")//
    public String encryption(@RequestBody AppCodeApiParam param) throws Exception {
        //对密码进行加密   盐为用户密码明文
        String pwd = param.getNewpassword();
        String Md5Pwd = MdUtils.md5(pwd,pwd);

        return Md5Pwd;

    }