MyBatis-Plus入门Demo详解

一.简介:

引用官方文档(本文主要参考官方文档示例):

MyBatis-Plus（简称 MP）是一个 MyBatis 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。

愿景

我们的愿景是成为 MyBatis 最好的搭档，就像魂斗罗中的 1P、2P，基友搭配，效率翻倍。(更多文档介绍请点击进入查看)

二.SpringBoot与MyBatis-plus的整合

这里我们使用SpringBoot引入依赖,当然非SpringBoot项目的引入也是一样的,为了统一,这里不做过多累述.正如官方所说，mybatis-plus在mybatis的基础上只做增强不做改变，因此其与spring的整合亦非常简单。只需把mybatis的依赖换成mybatis-plus的依赖，再把sqlSessionFactory换成mybatis-plus的即可。接下来看具体操作：

1.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 http://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>2.1.6.RELEASE</version><relativePath/> <!-- lookup parent from repository --></parent><groupId>com.hmoe</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>org.projectlombok</groupId><artifactId>lombok</artifactId><optional>true</optional></dependency><!--druid==>阿里巴巴数据库连接池--><dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>1.0.25</version></dependency><!--2)spring dao层依赖--><dependency><groupId>org.springframework</groupId><artifactId>spring-jdbc</artifactId><version>4.3.14.RELEASE</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-tx</artifactId><version>4.3.14.RELEASE</version></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.35</version></dependency><!--mp的依赖--><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.1.2</version></dependency><dependency><groupId>com.h2database</groupId><artifactId>h2</artifactId><scope>runtime</scope></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build></project>

2.在 `application.yml` 配置文件中添加 H2 数据库的相关配置：

# DataSource Config
spring:datasource:driver-class-name: com.mysql.jdbc.Driverurl: jdbc:mysql://localhost:3306/test03username: rootpassword: test# Logger Config
logging:level:com.baomidou.mybatisplus.samples.quickstart: debug

3.数据库建表语句

DROP TABLE IF EXISTS user;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, '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');

4.编写实体类 `User.java`（此处使用了 Lombok 简化代码）

@Data
public class User {private Long id;private String name;private Integer age;private String email;
}

5.编写Mapper类 `UserMapper.java`

public interface UserMapper extends BaseMapper<User> {}

6.添加测试类，进行功能测试：

@RunWith(SpringRunner.class)
@SpringBootTest
public class SampleTest {@Autowiredprivate UserMapper userMapper;@Testpublic void testSelect() {System.out.println(("----- selectAll method test ------"));List<User> userList = userMapper.selectList(null);Assert.assertEquals(5, userList.size());userList.forEach(System.out::println);}}

测试结果如下: