记录我的第一个MyBatis-Plus例子

第一步，数据库表

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’
);

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’);

数据库（MySQL）截图:

第二步，pom引入jar包

先看看目录结构：

pom文件：

// An highlighted block
<?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>
    <!--引入springboot父依赖-->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>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>
        <!--lombok插件，需先在IDEA安装，可自行百度-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <!--注意：之前的mybatis和springboot整合要删掉-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.0.6</version>
        </dependency>

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

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

第三步：

启动类：

需要加上@MapperScan("com.example.demo.Mapper")
后面是扫描的mapper路径

实体类：

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

注意：这里@Data是使用了lombok插件，这里不详细叙述

application.properties

#DataSoure Config
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/sys_test
spring.datasource.username=root
spring.datasource.password=********

在编写一个mapper接口

 public interface UserMapper extends BaseMapper<User> {
}

第四步，编写测试类

package com.example.demo;

import com.example.demo.Mapper.UserMapper;
import com.example.demo.Pojo.User;
import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import javax.annotation.Resource;
import java.util.List;

@RunWith(SpringRunner.class)
@SpringBootTest
public class DemoApplicationTests {

    @Resource
    private UserMapper userMapper;

    @Test
    public void contextLoads() {
        System.out.println("测试查询全部开始......");
        List<User> list = userMapper.selectList(null);
        Assert.assertEquals(5,list.size());
        list.forEach(System.out::println);
    }

}

执行结果如下图所示代表成功