MyBatis-Plus入门

mybatis-plus官网

https://mp.baomidou.com/

简介

MyBatis-Plus (opens new window)（简称 MP）是一个 MyBatis (opens new window)的增强工具，在 MyBatis 的基础上只做增强不做改变，为简化开发、提高效率而生。

快速入门案例

创建数据库

mybatis-plus

创建user表

对应数据库脚本如下

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)
);

插入数据

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');

创建SpringBoot工程

引入依赖

<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>3.3.1</version>
        </dependency>

        <!--mysql依赖-->
        <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>
            <optional>true</optional>
        </dependency>
    </dependencies>

然后刷新maven

在配置文件中配置mysql相关配置

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://192.168.91.135:3306/mybatis_plus?serverTimezone=GMT%2B8
spring.datasource.username=root
spring.datasource.password=820721wu


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

编写pojo实体类

package com.wxit.mybatisplus.pojo;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import lombok.Data;

/**
 * @Author wj
 **/
@Data
public class User {
    /*主键策略*/
    @TableId(type = IdType.ASSIGN_ID)
    private Long id;
    private String name;
    private Integer age;
    private String email;
}

添加mapper

编写Mapper接口

package com.wxit.mybatisplus.mapper;

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

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

在 Spring Boot 启动类中添加 @MapperScan 注解，扫描 Mapper 文件夹

package com.wxit.mybatisplus;

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

@SpringBootApplication
@MapperScan("com.wxit.mybatisplus.mapper")
public class MybatisPlusApplication {

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

}

测试

package com.wxit.mybatisplus;

import com.wxit.mybatisplus.mapper.UserMapper;
import com.wxit.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.List;

@SpringBootTest
class MybatisPlusApplicationTests {

    @Autowired
    private UserMapper userMapper;

    @Test
    void contextLoads() {
        List<User> users = userMapper.selectList(null);
        System.out.println(users);
    }

    @Test
    public void testAdd(){
        User user = new User();
        user.setName("吴杰");
        user.setAge(21);
        user.setEmail("17372@qq.com");
        int insert = userMapper.insert(user);
        System.out.println("受影响的行数为" + insert);
    }

}

得到结果