maven的springboot整合mybatis

1.先看项目结构图

2.pom依赖

    <!--springboot-->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.0</version>
        <relativePath></relativePath>
    </parent>
    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <!--springboot-->
        <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>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
            <version>2.7.0</version>
        </dependency>
        <!--整合-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.2.2</version>
        </dependency>
        <!--mybatis-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.9</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.44</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.16</version>
        </dependency>
        <!--lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>

 2.配置文件application.yml

server:
  port: 8080
spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/test
    username: root
    password: 123456
mybatis:
  mapper-locations: classpath:com.ty.mapper/*.xml
  type-aliases-package: com.ty.bean
logging:
  level:
    com.ty.mapper: debug

3.创建启动类程序入口

package com.ty;

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


@MapperScan("com.ty.mapper")
@SpringBootApplication
public class Application {
    public static void main(String[] args){
        SpringApplication.run(Application.class,args);
    }
}

4.写三层架构、bean、controller、mapper、service……

5.写映射文件mapper.xml

<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.ty.mapper.UserMapper">
    <select id="selectUser" parameterType="user" resultType="User">
        select * from user where username = #{username} and password = #{password}
    </select>
</mapper>

6.数据库表的创建