1、准备开发环境
Idea：idea 2019.2
JDK：JDK8+
构建工具：maven 3.6.1
MySQL版本：MySQL 5.7
Spring Boot：2.6.3
MyBatis-Plus：3.5.1
2、创建数据库及表
（1）创建表
CREATE DATABASE `mybatis_plus`;
use `mybatis_plus`;
DROP TABLE IF EXISTS user;
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;
（2）添加数据
DELETE FROM user;
INSERT INTO user (id, name, age, email) VALUES
(1, 'Jone', 18, 'test1@baomidou.com'),
(2, 'Jack', 20, 'test2@baomidou.com'),
(3, 'Tom', 28, 'test3@baomidou.com'),
(4, 'Sandy', 21, 'test4@baomidou.com'),
(5, 'Billie', 24, 'test5@baomidou.com');
3、创建Spring Boot工程
（1）初始化工程
使用 Spring Initializr 快速初始化一个 Spring Boot 工程
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（2）引入依赖
<?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>2.6.3</version>
<relativePath/>
</parent>
<groupId>com.xilc</groupId>
<artifactId>mybatis-plus-demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>mybatis-plus-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-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.5.1</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
（3）idea中安装lombok插件
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4、配置application.yml
spring:
datasource:
driver-class-name: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://192.168.1.30:3306/mybatis_plus?characterEncoding=utf-8&useSSL=false
username: root
password: root
注意：
1、驱动类driver-class-name
Spring Boot 2.0（内置jdbc5驱动），驱动类使用 com.mysql.jdbc.Driver
Spring Boot 2.1及以上（内置jdbc8驱动），驱动类使用 com.mysql.cj.jdbc.Driver
否则运行时候会有 WARN 信息
2、连接地址url
MySQL5.7版本的url：
jdbc:mysql://localhost:3306/mybatis_plus?characterEncoding=utf-8&useSSL=false
MySQL8.0版本的url：
jdbc:mysql://localhost:3306/mybatis_plus?
serverTimezone=GMT%2B8&characterEncoding=utf-8&useSSL=false
否则运行测试用例报告如下错误：
java.sql.SQLException: The server time zone value 'Öйú±ê׼ʱ¼ä' is unrecognized or represents more
5、创建启动类
在Spring Boot启动类中添加@MapperScan注解，扫描mapper包
@SpringBootApplication
@MapperScan("com.xilc.mybatisplus.mapper")
public class MybatisPlusApp {
public static void main(String[] args) {
SpringApplication.run(MybatisPlusApp.class, args);
}
}
6、添加实体类
@Data
public class User {
private Long id;
private String name;
private Integer age;
private String email;
}
7、添加mapper
BaseMapper是MyBatis-Plus提供的模板mapper，其中包含了基本的CRUD方法，泛型为操作的实体类型
public interface UserMapper extends BaseMapper<User> {
}
8、测试
@SpringBootTest
class MybatisPlusTests {
@Autowired
UserMapper userMapper;
@Test
void testList() {
List<User> list = userMapper.selectList(null);
list.forEach(System.out::println);
}
}
测试结果：
User(id=1, name=Jone, age=18, email=test1@baomidou.com)
User(id=2, name=Jack, age=20, email=test2@baomidou.com)
User(id=3, name=Tom, age=28, email=test3@baomidou.com)
User(id=4, name=Sandy, age=21, email=test4@baomidou.com)
User(id=5, name=Billie, age=24, email=test5@baomidou.com)
9、添加日志
在application.yml中配置日志输出
mybatis-plus:
configuration:
log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
控制台打印效果：
==> Preparing: SELECT id,name,age,email FROM user
==> Parameters:
<== Columns: id, name, age, email
<== Row: 1, Jone, 18, test1@baomidou.com
<== Row: 2, Jack, 20, test2@baomidou.com
<== Row: 3, Tom, 28, test3@baomidou.com
<== Row: 4, Sandy, 21, test4@baomidou.com
<== Row: 5, Billie, 24, test5@baomidou.com
<== Total: 5
