解决数据库和实体类的下划线或者驼峰不一致 然后数据缺少问题
1、#mybatis.configuration.mapUnderscoreToCamelCase=true
mybatis.configuration.map-underscore-to-camel-case=true
2、
@Results({
@Result(column = "cover_img",property = "coverImg"),
@Result(column = "create_time",property ="createTime")
})