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MyBatis-Plus + Spring Boot入门案例

• pom.xml依赖
• application.yml配置
• 继承BaeMapper< T >
• 使用 @Mapper 或 @MapperScan + Repository
• 使用Lombok插件简化实体类 @Data

1、创建数据库与表

CREATE DATABASE `mybatis_plus` 

USE `mybatis_plus`;

DROP TABLE IF EXISTS `user`;

CREATE TABLE `user` (
  `id` bigint NOT NULL COMMENT '主键ID',
  `name` varchar(30) DEFAULT NULL COMMENT '姓名',
  `age` int DEFAULT NULL COMMENT '年龄',
  `email` varchar(50) DEFAULT NULL COMMENT '邮箱',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb3;


insert  into `user`(`id`,`name`,`age`,`email`) values 
(1,'Jone',18,'test1@qq.com'),
(2,'Jack',20,'test2@qq.com'),
(3,'Tom',28,'test3@qq.com'),
(4,'Sandy',21,'test4@qq.com'),
(5,'Billie',24,'test5@qq.com'),
(6,'HeXi',20,'test6@qq.com');
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2、创建SpringBoot工程

3、选择版本与技术集SQL（MySQL Driver）

4、添加依赖pom.xml，记得配置与刷新Maven

        
        <dependency>
            <groupId>com.baomidougroupId>
            <artifactId>mybatis-plus-boot-starterartifactId>
            <version>3.5.1version>
        dependency>

        
        <dependency>
            <groupId>org.projectlombokgroupId>
            <artifactId>lombokartifactId>
            <optional>trueoptional>
        dependency>
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5、配置application.yml

spring:
  # 配置数据源信息
  datasource:
    # 配置数据源类型
    type: com.zaxxer.hikari.HikariDataSource
    # 配置连接数据库的各个信息
    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: 111111

# 日志
mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

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6、创建pojo

package com.sgz.pojo;

import lombok.Data;

@Data
public class User {

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

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7、创建Mapper接口继承BaseMapper< T >

package com.sgz.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.sgz.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;

@Repository
//@Mapper  // 这里使用@Mapper后，引导类的MapperScan就可以去掉了
public interface UserMapper extends BaseMapper<User> {
}

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8、引导类使用@MapperScan

package com.sgz;

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

@SpringBootApplication
// 用于扫描mapper接口所在的包
@MapperScan("com.sgz.mapper") // mapper中使用@Mapper，这里的注解就可以去掉了
public class MybaitsplusSpringbootDemoApplication {

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

}

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9、测试类

package com.sgz;

import com.sgz.mapper.UserMapper;
import com.sgz.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;
import java.util.Map;

@SpringBootTest
public class MyBatisPlusTest {

    @Autowired
    private UserMapper userMapper;

    // 查询全部
    @Test
    void testSelectList() {
        // SELECT id,name,age,email FROM user
        // 通过条件查询全部数据，调用BaseMapper，如果没有条件则设置为null
        userMapper.selectList(null);
    }
}


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