上半部分搭建springboot 简单使用数据库查询
添加链接描述

在impl接口实现操作

如

package com.service.impl;
import com.dao.UserMapper;
import com.pojo.User;
import com.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class UserServiceImpl implements UserService {@Autowiredprivate UserMapper userMapper;@Overridepublic List<User> dade() {return userMapper.selectAll();}@Overridepublic User oneUser(Long id) {return userMapper.selectByPrimaryKey(id);}
}

1、selectAll查所有

	@Overridepublic List<User> dade() {return userMapper.selectAll();}

2、selectByPrimaryKey根据id查询

    @Overridepublic User oneUser(Long id) {return userMapper.selectByPrimaryKey(id);}