package com.example.demo.service import com.example.demo.dao.UserMapper import com.example.demo.entity.User import org.springframework.beans.factory.annotation.Autowired import org.springframework.stereotype.Service @Service class MyBatisPlusMapper { @Autowired private lateinit var mapper: UserMapper fun save(user: User) = if (mapper.selectById(user.id) != null) mapper.updateById(user) == 1 else mapper.insert(user) == 1 fun delete(id: Long) = mapper.deleteById(id) == 1 fun select(id: Long): User? = mapper.selectById(id) fun selectAll(): List? = mapper.selectList(null) }