mybatis-plus入门笔记

java零基础自学点击了解:https://how2j.cn?p=81777

目录

一:数据库准备

二:创建springboot项目

三:安装lombok插件

四:配置application.properties文件

五:写代码

---

一:数据库准备

1.创建数据库

 

create database mybatis_plus;

2.创建table

 

CREATE TABLE user(

    id BIGINT(20) NOT NULL COMMENT '主键ID',

    name VARCHAR(30) NULL DEFAULT NULL COMMENT '姓名',

    age INT(11) NULL DEFAULT NULL COMMENT '年龄',

    email VARCHAR(50) NULL DEFAULT NULL COMMENT '邮箱',

    PRIMARY KEY (id)

);

3.导入数据

 

INSERT INTO user(id,name,age,email)VALUES

(1,'Jone',18,'[email protected]'),

(2,'Jack',20,'[email protected]'),

(3,'Tom',28,'[email protected]'),

(4,'Sandy',24,'[email protected]'),

(5,'Billie',30,'[email protected]');

 

二:创建springboot项目

1:创建spring lnitializr形式的springboot项目mpdemo

 

2:复制下面代码到pom文件

 

<dependencies>

    <dependency>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter</artifactId>

    </dependency>

​

    <dependency>

        <groupId>org.springframework.boot</groupId>

      <artifactId>spring-boot-starter-test</artifactId>

        <scope>test</scope>

        <exclusions>

            <exclusion>

                <groupId>org.junit.vintage</groupId>

                <artifactId>junit-vintage-engine</artifactId>

            </exclusion>

        </exclusions>

    </dependency>

    <!--mybatis-plus-->

    <dependency>

        <groupId>com.baomidou</groupId>

        <artifactId>mybatis-plus-boot-starter</artifactId>

        <version>3.0.5</version>

    </dependency>

    <!--mysql-->

    <dependency>

        <groupId>mysql</groupId>

        <artifactId>mysql-connector-java</artifactId>

    </dependency>

    <!--lombok用来简化实体类-->

    <dependency>

        <groupId>org.projectlombok</groupId>

        <artifactId>lombok</artifactId>

   </dependency>

</dependencies>

3:点击右下方import Change下载依赖

 

三:安装lombok插件

1:操作步骤:file>seting...>plugins

2:搜索框搜索:lombok

 

3:重启idea即可

四:配置application.properties文件

1:复制以下内容到.properties文件

 

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

spring.datasource.url=jdbc:mysql://localhost:3306/mybatis_plus?serverTimezone=GMT%2B8

spring.datasource.username=root

spring.datasource.password=123456

2:修改自己数据量username和password

五:写代码

1:创建实体类entity.Uaer

 

import lombok.Data;

​

/**

 * @Author: ZhangDeChen

 * @Date: 2020/6/4 20:28

 */

@Data

public class User {

    private Long id;

    private String name;

    private Integer age;

    private String email;

}

2:创建mapper.UserMapper

 

​

3:在启动类中添加:@MapperScan("xyz.dechen.mpdemo.mapper")括号中为项目mapper包的路径

 

4:在测试类中复制以下代码,测试.

 

import org.junit.jupiter.api.Test;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.boot.test.context.SpringBootTest;

import xyz.dechen.mpdemo.entity.User;

import xyz.dechen.mpdemo.mapper.UserMapper;

​

import java.util.List;

​

@SpringBootTest

class MpdemoApplicationTests {

    @Autowired

    private UserMapper userMapper;

​

    //查询user表中的所有数据

    @Test

    public void findAll() {

        List<User> users=userMapper.selectList(null);

        System.out.println(users);

    }

​

}

5:测试成功: