SpringBoot 配置连接 MySQL 数据库

一：引入依赖

1
2
3
4
5
6
7
8
9
10
11
12
13
14
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

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

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

二：编辑 yaml 文件

1
2
3
4
5
6
7
8
9
10
spring:
  application:
    name: Developer
  datasource:
    username: root
    password: root
    url: jdbc:mysql://localhost:3306/aaa?serverTimezone=UTC&useUnicode=true&characterEcoding=utf-8
    driver-class-name: com.mysql.cj.jdbc.Driver
server:
  port: 8088

三：配置包扫描

SpringBoot 拥有默认的包扫描机制，启动类所在当前包及其包的子类都会默认被扫描；

有时会因为 Bean 和启动类不在一个文件夹下，导致扫描不到引起的注解失败问题。

如何修改包扫描的位置？

方法一：

在启动类 SpringBootApplication 注解中配置 scanBasePackages即可，如下：

1
2
3
4
5
6
7
@SpringBootApplication(scanBasePackages = {"cn.aiyingke.developer.mysql"})
public class DeveloperApplication {
    public static void main(String[] args) {
        SpringApplication.run(DeveloperApplication.class, args);
        System.out.println("Program startup completed!");
    }
}

也可以配置多个包路径；

1
@SpringBootApplication(scanBasePackages = {"cn.aiyingke.developer.mysql","cn.aiyingke.developer.mysql.ebean"})

方法二：

在启动类里面添加 @ComponentScan 注解配置 basePackages；

1
2
3
4
5
6
7
8
@SpringBootApplication
@ComponentScan("cn.aiyingke.developer.mysql")
public class DeveloperApplication {
    public static void main(String[] args) {
        SpringApplication.run(DeveloperApplication.class, args);
        System.out.println("Program startup completed!");
    }
}

四：测试类

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
/**
 * Author: Rupert Tears
 * Date: Created in 22:11 2022/11/21
 * Description: Thought is already is late, exactly is the earliest time.
 */
@RestController
@RequestMapping("/mysql")
public class JdbcController {
    final
    JdbcTemplate jdbcTemplate;

    public JdbcController(JdbcTemplate jdbcTemplate) {
        this.jdbcTemplate = jdbcTemplate;
    }

    @GetMapping("/mdtList")
    public List<Map<String, Object>> mdtList() {
        String sql = "select * from mdt";
        return jdbcTemplate.queryForList(sql);
    }
}