Mybatis新增save结束后自动返回主键id

 <!-- 插入数据:返回记录主键id值 -->
<insert id="insert" useGeneratedKeys="true" keyProperty="id"  keyColumn="id">
        insert  into stu (name,age) values (#{name},#{age})
</insert>

https://www.cnblogs.com/charlypage/p/11253610.html

https://blog.csdn.net/xy405580364/article/details/102837263

注：并不是返回的数据里获取id，而是添加的对象里添加成功后会自动添加id