2-MyBatisPlus教程（HelloWorld）

 1 DROP TABLE IF EXISTS user;
 2 
 3 CREATE TABLE user
 4 (
 5     id BIGINT(20) NOT NULL COMMENT ‘主键ID‘,
 6     name VARCHAR(30) NULL DEFAULT NULL COMMENT ‘姓名‘,
 7     age INT(11) NULL DEFAULT NULL COMMENT ‘年龄‘,
 8     email VARCHAR(50) NULL DEFAULT NULL COMMENT ‘邮箱‘,
 9     PRIMARY KEY (id)
10 );
11 
12 
13 DELETE FROM user;
14 
15 INSERT INTO user (id, name, age, email) VALUES
16 (1, ‘Jone‘, 18, ‘test1@baomidou.com‘),
17 (2, ‘Jack‘, 20, ‘test2@baomidou.com‘),
18 (3, ‘Tom‘, 28, ‘test3@baomidou.com‘),
19 (4, ‘Sandy‘, 21, ‘test4@baomidou.com‘),
20 (5, ‘Billie‘, 24, ‘test5@baomidou.com‘);

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.6.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.tongjun</groupId>
    <artifactId>mp-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>mp-demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </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>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/mp-demo?serverTimezone=GMT%2B8
spring.datasource.username=root
spring.datasource.password=123456

package com.tongjun.mpdemo.entitiy;

import lombok.Data;

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

package com.tongjun.mpdemo.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.tongjun.mpdemo.entitiy.User;

public interface UserMapper extends BaseMapper<User> {

}

package com.tongjun.mpdemo;

import com.tongjun.mpdemo.entitiy.User;
import com.tongjun.mpdemo.mapper.UserMapper;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;

import javax.annotation.Resource;
import java.util.List;

@SpringBootTest
class MpDemoApplicationTests {


    @Resource
    private UserMapper userMapper;

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

}