<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.2.9</version>
</dependency>

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.2.2</version>
</dependency>

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

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

public class Book {
    private Integer id;
    private String name;
    private double price;
    private String author;
    private int count;
}

@Mapper
public interface  BookDao {
    @Select("select * from book where id = #{id}")
    public Book getById(Integer id);
}

spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/ssm_db
    username: root
    password: root
    type: com.alibaba.druid.pool.DruidDataSource

spring:
  datasource:
    druid:
      driver-class-name: com.mysql.jdbc.Driver
      url: jdbc:mysql://localhost:3306/ssm_db
      username: root
      password: root

@SpringBootTest
class Springboot07DruidApplicationTests {

    @Autowired
    private BookDao bookDao;

    @Test
    void contextLoads() {
        System.out.println(bookDao.getById(1));
    }

}