1、使用postman 进行post接口测试

{
    "timestamp": "2021-12-18T17:04:42.820+0000",
    "status": 415,
    "error": "Unsupported Media Type",
    "message": "Content type 'text/plain;charset=UTF-8' not supported",
    "path": "/add"
}

2、解决方法：

将数据格式切换成 JSON