Mybatis 快速入门

创建maven工程

准备数据

CREATE DATAbase `mybatis_db` ;
USE `mybatis_db`;
DROp TABLE IF EXISTS `user`;
CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(50) DEFAULT NULL,
  `password` varchar(50) DEFAULT NULL,
  `age` int(3) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;
insert  into `user`(`id`,`username`,`age`,`age`) values (1,'UZI','1234',19),(2,'PDD','123',25);

导入依赖

 
            org.mybatis
            mybatis
            3.5.7
        
        
            log4j
            log4j
            1.2.17
        
        
            org.projectlombok
            lombok
            1.18.22
        
        
            mysql
            mysql-connector-java
            8.0.13
        
        

创建数据库的信息文件properties

jdbc.url=jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone = GMT
jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.username=root
jdbc.password=317311

创建mybatis的配置文件

实体类 位置： com.hgzy.pojo
因为我这加入了lombok依赖 注解生成setget方法

package com.hgzy.pojo;

import lombok.Data;
import lombok.ToString;

@Data
@ToString
public class User {
    private Integer id ;
    private String user;
    private String pwd;
    private Integer age ;
}

dao 层 位置：com.hgzy.dao

package com.hgzy.dao;

import com.hgzy.pojo.User;

public interface UserDao {
    User findUserById(Integer id);
}

dao 层xml文件及 位置：com.hgzy.dao

    
        select * from user where id=#{id}
    

调试方法

 public static void main(String[] args) throws IOException {
        //定义mybatis配置文件的路径
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        //获取Sqlsession对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //获取UserDao实现类对象
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        //调用方法测试
        List userList = userDao.findAll();
        System.out.println(userList);
        //释放资源
        sqlSession.close();
    }