MybatisPlus入门程序

Posted 2021-03-02 LonZyuan

参考资料：MybatisPlus官网

 

环境搭建

创建数据库

CREATE DATABASE `mybatisplus`
 ​
 USE `mybatisplus`
 ​
 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)
 );
 ​
 DELETE FROM USER;
 ​
 INSERT INTO USER (id, NAME, age, email) VALUES
 (1, \'Jone\', 18, \'[e-mail]\'),
 (2, \'Jack\', 20, \'[e-mail]\'),
 (3, \'Tom\', 28, \'[e-mail]\'),
 (4, \'Sandy\', 21, \'[e-mail]\'),
 (5, \'Billie\', 24, \'[e-mail]\');

数据库名为 mybatisplus，表名为 user

 

创建一个springboot项目，一个web依赖即可

 

导入相关maven依赖

mysql

<dependency>
     <groupId>mysql</groupId>
     <artifactId>mysql-connector-java</artifactId>
 </dependency>

 

Lombok(不是必须品，只是可以偷点懒)

<dependency>
     <groupId>org.projectlombok</groupId>
     <artifactId>lombok</artifactId>
     <version>1.18.12</version>
     <optional>true</optional>
 </dependency>

 

mybatis-plus

<dependency>
     <groupId>com.baomidou</groupId>
     <artifactId>mybatis-plus-boot-starter</artifactId>
     <version>3.0.5</version>
 </dependency>

 

配置application.properties

# mysql
 spring.datasource.username=root
 spring.datasource.password=123456
 spring.datasource.url=jdbc:mysql://localhost:3306/mybatisplus?useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT%2B8
 # 东8时区，serverTimezone=GMT%2B8
 spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
 ​
 # 配置日志,方便查看SQL语句
 mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

 

实体类Pojo

User

package com.zy.pojo;
 ​
 import lombok.AllArgsConstructor;
 import lombok.Data;
 import lombok.NoArgsConstructor;
 ​
 @Data
 @AllArgsConstructor
 @NoArgsConstructor
 public class User {
 ​
     private Long id;
     private String name;
     private Integer age;
     private String email;
 ​
 }

 

mapper接口

　　实现 BaseMapper 接口

UserMapper

package com.zy.mapper;
 ​
 import com.baomidou.mybatisplus.core.mapper.BaseMapper;
 import com.zy.pojo.User;
 import org.springframework.stereotype.Repository;
 ​
 @Repository //代表持久层
 ​
 //在对应的mapper上面 继承 基本的接口BaseMapper
 public interface UserMapper extends BaseMapper<User> {
     //继承之后，所有的CRUD就完成了
 ​
 }

 

主启动类扫描mapper

 
package com.zy;
 ​
 import org.mybatis.spring.annotation.MapperScan;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 ​
 //扫描mapper文件夹
 @MapperScan("com.zy.mapper")
 ​
 @SpringBootApplication
 public class DemoApplication {
 ​
     public static void main(String[] args) {
         SpringApplication.run(DemoApplication.class, args);
     }
 ​
 }

 

测试查找全部用户

@Test
 public void select(){
 ​
     //查询全部用户
     List<User> users = userMapper.selectList(null);
     users.forEach(System.out::println);
 ​
 }

结果