mybatis-plus 初识

注意：

数据库中的字段 last_name 与 实体类中的 lastName 一致

官网：https://mp.baomidou.com/guide/#%E7%89%B9%E6%80%A7

一、环境

1、配置maven

<!--        数据库驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.11</version>
        </dependency>
<!--        lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
<!--        mybatis-plus-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.3.2</version>
        </dependency>

2、连接数据库

位置 application.yaml

spring:
  datasource:
    username: root
    password: 123456
    url: jdbc:mysql://127.0.0.1:3306/mybatisplus?useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=UTC&allowPublicKeyRetrieval=true
    driver-class-name: com.mysql.cj.jdbc.Driver

三、编码

1、编写实体类

pojo-----User.java

package com.wt.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
    private Long id;
    private String name;
    private Integer age;
    private String email;
}

2、编写mapper接口

mapper----UserMapper

package com.wt.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.wt.pojo.User;

public interface UserMapper extends BaseMapper<User> {
    
}

3、在springboot启动程序入口类添加注解

@MapperScan("com.wt.mapper")

package com.wt;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@MapperScan("com.wt.mapper")
@SpringBootApplication
public class Springboot01Application {

    public static void main(String[] args) {
        SpringApplication.run(Springboot01Application.class, args);
    }

}

4、测试

    @Test
    public void sampleTest(){
        List<User> userList = userMapper.selectList(null);
        for (User user : userList) {
            System.out.println(user);
        }
    }