MyBatis-Plus的入坑指南

MyBatis-Plus的入坑指南

首先，要使用这玩意，你得需要一个环境，那玩意没有就可以关闭窗口了

• 拥有 Java 开发环境以及相应 IDE
• 熟悉 Spring Boot
• 熟悉 Maven

然后你需要一张测试的表，我直接拿官网的例子过来

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, '[email protected]'),
(2, 'Jack', 20, '[email protected]'),
(3, 'Tom', 28, '[email protected]'),
(4, 'Sandy', 21, '[email protected]'),
(5, 'Billie', 24, '[email protected]');

数据就和下面这样

然后你需要生成一个测试工程，推荐用idea的自带，也可以去spring.io去生成一个，为了避免有坑，个人建议springboot版本最好是2.2以后的版本

添加依赖

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.2.5.RELEASE</version>
    <relativePath/>
</parent> 

引入jar包（官网里面是用的H2,我用的MySQL）

         <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>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.3.1.tmp</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.44</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>

配置yml

spring:
  datasource:
    #数据库url
    url: jdbc:mysql://localhost:3306/demo?useUnicode=true&characterEncoding=utf8&allowMultiQueries=true&serverTimezone=GMT%2B8&useSSL=false
    # 数据库访问账户
    username: root
    # 数据库访问密码
    password: root123
    driver-class-name: com.mysql.jdbc.Driver

添加mapper扫描

package com.master.mybatiesplus;

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

@SpringBootApplication
@MapperScan("com.master.mybatiesplus.mapper.*")
public class MybatiesPlusApplication {

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

}

编码

实体类

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

mapper

public interface UserMapper extends BaseMapper<User> {
}

测试类

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

    @Autowired
    private UserMapper userMapper;

    @Test
    public void testSelect() {
        System.out.println(("----- selectAll method test ------"));
        List<User> userList = userMapper.selectList(null);
        Assert.assertEquals(5, userList.size());
        userList.forEach(System.out::println);
    }

}

运行测试

User(id=1, name=Jone, age=18, email=test1@baomidou.com)
User(id=2, name=Jack, age=20, email=test2@baomidou.com)
User(id=3, name=Tom, age=28, email=test3@baomidou.com)
User(id=4, name=Sandy, age=21, email=test4@baomidou.com)
User(id=5, name=Billie, age=24, email=test5@baomidou.com)

小总结

运行到这说明前面的配置和环境都是没有问题的，接下来进一步操作