import tk.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.transaction.annotation.EnableTransactionManagement;
@SpringBootApplication
@EnableTransactionManagement //開啟書屋管理注解模式 最新的版本可以省略
@MapperScan("com.xz.springboot.mapper") //掃描該包下所有的接口并為該接口生成實現類
public class Springboot01Application {
  public static void main(String[] args) {
    SpringApplication.run(Springboot01Application.class, args);
  }
}

import com.xz.springboot.bean.User;
import com.xz.springboot.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import java.util.List;
@Service
public class UserService {
    @Autowired
    private UserMapper userMapper;
    public List<User> queryAll(){
      System.out.println("熱部署");
      return userMapper.findAll();
    }
  @Transactional
  public void deleteById(Integer id) {
      userMapper.deleteById(id);
     // int c=10/0;
  }
}