【Spring Boot】service 业务层简单使用

• 在controller同级目录下创建service
  

  package com.spring2.service;

  import com.spring2.entity.User;
  import com.spring2.mapper.UserMapper;
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.stereotype.Service;

  @Service
  public class UserService {

    @Autowired
    private UserMapper userMapper;
  
    public int save(User user){
        if(user.getId() == null){
            //有id 新增
           return userMapper.insert(user);
        }else{
           return userMapper.update(user);
        }
    }

  }

• 在controller里出入service