<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jdbc</artifactId>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>

spring:
  datasource:
    username: root
    password: 123
    url: jdbc:mysql://127.0.0.1:3306/jdbc
    driver-class-name: com.mysql.jdbc.Driver

@ConditionalOnMissingBean({DataSource.class})
@ConditionalOnProperty(
    name = {"spring.datasource.type"}
)
static class Generic {
    Generic() {
    }
        //通過(guò) build 創(chuàng)建數(shù)據(jù)源的。利用反射創(chuàng)建 type 類(lèi)型的數(shù)據(jù)源，并綁定相關(guān)屬性。
    @Bean
    public DataSource dataSource(DataSourceProperties properties) {
        return properties.initializeDataSourceBuilder().build();
    }
}

public class DataSourceAutoConfiguration {
    private static final Log logger = LogFactory.getLog(DataSourceAutoConfiguration.class);

    public DataSourceAutoConfiguration() {
    }

    @Bean
    @ConditionalOnMissingBean
    public DataSourceInitializer dataSourceInitializer(DataSourceProperties properties, ApplicationContext applicationContext) {
        return new DataSourceInitializer(properties, applicationContext);
    }
    //......
}

class DataSourceInitializer implements ApplicationListener<DataSourceInitializedEvent> {
//......
}

//運(yùn)行建表語(yǔ)句
private void runSchemaScripts() {
    List<Resource> scripts = this.getScripts("spring.datasource.schema", this.properties.getSchema(), "schema");
    if(!scripts.isEmpty()) {
        String username = this.properties.getSchemaUsername();
        String password = this.properties.getSchemaPassword();
        this.runScripts(scripts, username, password);

        try {
            this.applicationContext.publishEvent(new DataSourceInitializedEvent(this.dataSource));
            if(!this.initialized) {
                this.runDataScripts();
                this.initialized = true;
            }
        } catch (IllegalStateException var5) {
            logger.warn("Could not send event to complete DataSource initialization (" + var5.getMessage() + ")");
        }
    }

}
//運(yùn)行操作數(shù)據(jù)的 sql語(yǔ)句
private void runDataScripts() {
    List<Resource> scripts = this.getScripts("spring.datasource.data", this.properties.getData(), "data");
    String username = this.properties.getDataUsername();
    String password = this.properties.getDataPassword();
    this.runScripts(scripts, username, password);
}

spring:
  datasource:
    schema:
      - classpath: student.sql

@AutoConfigureAfter({DataSourceAutoConfiguration.class})
public class JdbcTemplateAutoConfiguration {
    @Bean
    @Primary
    @ConditionalOnMissingBean({JdbcOperations.class})
    public JdbcTemplate jdbcTemplate() {
        return new JdbcTemplate(this.dataSource);
    }
}

<!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.1.10</version>
</dependency>

spring:
  datasource:
    username: root
    password: 123
    url: jdbc:mysql://127.0.0.1:3306/jdbc
    driver-class-name: com.mysql.jdbc.Driver
    type: com.alibaba.druid.pool.DruidDataSource

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.1.1</version>
</dependency>

//指定這是一個(gè)操作數(shù)據(jù)庫(kù)的 mapper
@Mapper
public interface DepartmentMapper {

    @Select("select * from department where id=#{id}")
    public Department getDeptById(Integer id);
}

@Controller
public class DepartmentController {

    @Autowired
    private DepartmentMapper mapper;

    @GetMapping("/dept/{id}")
    public Department getDeptById(@PathVariable("id") Integer id){
        return mapper.getDeptById(id);
    }
}