mybatis项目雏形

第一步

创建普通maven项目或者springboot脚手架创建springboot项目
配置依赖：

<!--maven下的pom配置-->
    <parent>
        <artifactId>spring-boot-starter-parent</artifactId>
        <groupId>org.springframework.boot</groupId>
        <version>2.7.1</version>
    </parent>

    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.5.2</version>
        </dependency>

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

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.7.1</version>
            </plugin>
        </plugins>
    </build>

第二步

在resource里创建application.yml连接数据库

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/es?useSSL=false&characterEncoding=utf-8
    username: root
    password: 123456
    driver-class-name: com.mysql.jdbc.Driver

第三步

编写启动类

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

@SpringBootApplication
@MapperScan("edu.school.mybatises.Mapper")  //用来扫描mapper包
public class MybatisApplication {
    public static void main(String[] args) {
        SpringApplication.run(MybatisApplication.class,args);
    }
}

第四步

编写实体类

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

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

第五步

编写接口类，mybatis里的interface类称为mapper

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import edu.school.mybatises.entity.User;
import org.springframework.stereotype.Repository;

@Repository
public interface UserMapper extends BaseMapper<User> {
}
//继承basemapper类，里面有写好的基本crud操作

第六步

测试

import edu.school.mybatises.Mapper.UserMapper;
import edu.school.mybatises.entity.User;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import java.util.List;

@SpringBootTest
public class MyBatisTest {
    @Autowired
    private UserMapper userMapper;
    @Test
    void testSelect() {
        List<User> users = userMapper.selectList(null);
        users.forEach(System.out::println);
    }
}