SpringBoot框架——7.整合MybatisPlus

        这篇主要介绍Springboot整合MybatisPlus，另外介绍一个插件JBLSpringbootAppGen,以及一个经常用于测试的基于内存的h2数据库。

        Mybatisplus是mybatis的增强工具，和tk-mybatis相似，但功能更强大，可避免重复CRUD语句，先来一个简单入门：

1.安装一个插件：JBLSpringbootAppGen：

        File->Setting->Plugin: 搜索点击Install,重启IDEA

        这个工具主要用于创建启动类时自动创建配置文件。

2.新建一个modle: mybatis-plus-demo;

3.添加pom依赖：

<?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>

    <groupId>com.lxj</groupId>
    <artifactId>mybatis-plus-demo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.0.RELEASE</version>
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <mybatisplus.version>3.3.2</mybatisplus.version>
        <skipTests>true</skipTests>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency><!--基于内存的数据库-->
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>${mybatisplus.version}</version>
        </dependency>

        <dependency><!--测试框架-->
            <groupId>org.assertj</groupId>
            <artifactId>assertj-core</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency><!--简化实体类开发，加@Data注解不用写get、set方法-->
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

    </dependencies>
</project>

4.通过工具添加启动类： 

5.设置配置项：（注意每一项冒号后面有个空格！）

        自动创建的配置文件为yml，和properties文件比结构层级更清晰一些：

#Datasource Configspring:spring:
spring:
  datasource:
    driver-class-name: org.h2.Driver
    schema: classpath:db/schema-h2.sql
    data: classpath:db/data-h2.sql
    #y用于测试可随便写
    url: jdbc:h2:mem:test
    username: roottest
    passworld: test123

#Logger Config
logging:
  level:
    com.lxj.quickstart: debug

6.引入测试用的数据库：

        一个是创建表的sql文件：

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)
)

        一个是插入数据的sql文件：

DELETE FROM user;

INSERT INTO user (id,name,age,email) VALUES
(1,'Jone',18,'test1@abc.com'),
(2,'Jack',19,'test2@abc.com'),
(3,'Tom',20,'test3@abc.com'),
(4,'Sandy',18,'test4@abc.com'),
(5,'hahaha',19,'test5@abc.com'),
(6,'Billie',18,'test6@abc.com');

        将两个文件放到classpath下：

7.编写实体类：

package com.lxj.quickstart.entity;

import lombok.Data;

@Data
public class User {

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

}

        @Data注解可给类中属性自动添加get/set方法。

8.编写dao类：

package com.lxj.quickstart.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.lxj.quickstart.entity.User;

public interface UserMapper extends BaseMapper<User> {

}

9.启动类中别忘了添加扫描包路径：

@MapperScan("com.lxj.quickstart.mapper")

10.添加测试类测试：

package com.lxj.quickstart.mapper;

import com.lxj.quickstart.entity.User;
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 com.lxj.quickstart.mapper.UserMapper;
import java.util.List;

import static org.junit.Assert.*;
@RunWith(SpringRunner.class)
@SpringBootTest
public class UserMapperTest {

    @Autowired
    private UserMapper userMapper;

    @Test
    public void testSelect(){
        List<User> list = userMapper.selectList(null);
        list.forEach(System.out::println);
    }

}

11.结果：