springboot开发中以POST方式向后台传递json数据的时候参数值为null

contentType: “application/json; charset=utf-8”

https://blog.csdn.net/bxj19890514/article/details/83861349?utm_medium=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-3.channel_param&depth_1-utm_source=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-3.channel_param

https://blog.csdn.net/yelllowcong/article/details/79711429?utm_medium=distribute.pc_relevant.none-task-blog-title-3&spm=1001.2101.3001.4242