创建数据库和表并插入数据

CREATE DATABASE mybatis_plus;
USE mybatis_plus;
CREATE TABLE `user`(
  `id` BIGINT(20) NOT NULL COMMENT '主键ID',
  `name` VARCHAR(30)DEFAULT NULL COMMENT '姓名',
  `age` INT(11) DEFAULT NULL COMMENT '年龄',
  `email` VARCHAR(50) DEFAULT NULL COMMENT '邮箱',
  PRIMARY KEY(`id`)
)ENGINE=INNODB DEFAULT CHARSET=utf8;
INSERT INTO USER(id,NAME,age,email) VALUES
(1,'Jone',18,'test1@baomidou.com'),
(2,'jack',20,'test2@baomidou.com'),
(3,'tom',14,'test3@baomidou.com'),
(4,'sandy',28,'test4@baomidou.com'),
(5,'bill',50,'test5@baomidou.com');

构建项目

pom.xml

<?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>2.7.3</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.qrxqrx</groupId>
    <artifactId>mybatisplus</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>mybatisplus</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-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.5.1</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
    </dependencies>

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

</project>

application.yml

spring:
  datasource:
    type: com.zaxxer.hikari.HikariDataSource
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/mybatis_plus?serverTimezone=GMT%2B8&characterEncoding=utf-8&useSSL=false
    username: root
    password: 1234
mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

User

package com.qrxqrx.mybatisplus.pojo;

import lombok.*;

@NoArgsConstructor
@AllArgsConstructor
@Getter
@Setter
@EqualsAndHashCode
@ToString
public class User {

    private Long id;
    private String name;
    private Integer age;
    private String email;

}

UserMapper

package com.qrxqrx.mybatisplus.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.qrxqrx.mybatisplus.pojo.User;
import org.springframework.stereotype.Repository;

@Repository
public interface UserMapper extends BaseMapper<User> {
}

MybatisplusApplicationTests

package com.qrxqrx.mybatisplus;

import com.qrxqrx.mybatisplus.mapper.UserMapper;
import com.qrxqrx.mybatisplus.pojo.User;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.Arrays;
import java.util.HashMap;
import java.util.List;

@SpringBootTest
class MybatisplusApplicationTests {

    @Autowired
    private UserMapper userMapper;


    @Test
    public void testInsert() {
        User user = new User();
        user.setName("zhangsan");
        user.setAge(13);
        user.setEmail("abc@abc.com");
        int col = userMapper.insert(user);
        System.out.println(col);
        System.out.println(user.getId());
    }

    @Test
    public void testDeleteById() {
        int col = userMapper.deleteById(1566336946865758209L);
        System.out.println(col);
    }

    @Test
    public void testDeleteByMap() {
        HashMap<String, Object> map = new HashMap<>();
        map.put("name","zhangsan");
        map.put("age",13);
        int col = userMapper.deleteByMap(map);
        System.out.println(col);
    }

    @Test
    public void testDeleteBatchIds() {
        List<Long> list = Arrays.asList(1L, 2L, 3L);
        int col = userMapper.deleteBatchIds(list);
        System.out.println(col);
    }

    @Test
    public void testUpdateById() {
        User user = new User();
        user.setId(4L);
        user.setName("sandy");
        user.setAge(20);
        int col = userMapper.updateById(user);
        System.out.println(col);
    }

    @Test
    public void testSelectById() {
        User user = userMapper.selectById(1L);
        System.out.println(user);

    }

    @Test
    public void testSelectBatchIds() {
        List<Long> list = Arrays.asList(1L, 2L, 3L);
        List<User> users = userMapper.selectBatchIds(list);
        users.forEach(System.out::println);
    }

    @Test
    public void testSelectByMap() {
        HashMap<String, Object> map = new HashMap<>();
        map.put("name","jack");
        map.put("age","20");
        List<User> users = userMapper.selectByMap(map);
        users.forEach(System.out::println);

    }

    @Test
    public void testSelectList() {
        // 通过条件构造器查询一个List集合，若没有条件，则可以设置null为参数
        List<User> users = userMapper.selectList(null);
        users.forEach(System.out::println);
    }

}

MybatisplusApplication

package com.qrxqrx.mybatisplus;

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

@SpringBootApplication
@MapperScan("com.qrxqrx.mybatisplus.mapper")
public class MybatisplusApplication {

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

}