SpringBoot2学习（四）：数据库场景的自动配置与整合

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

<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.25</version>
</dependency>

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/mybatisdb
    username: root
    password: root
    driver-class-name: com.mysql.cj.jdbc.Driver
  jdbc:
    template:
      query-timeout: 3

package demo.boot.demo03;
import lombok.extern.slf4j.Slf4j;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.jdbc.core.JdbcTemplate;
@Slf4j
@SpringBootTest
class Demo03ApplicationTests {
    @Autowired
    JdbcTemplate jdbcTemplate;
    @Test
    void contextLoads() {
        String sql = "select count(*) from user";
        Long aLong = jdbcTemplate.queryForObject(sql, long.class);
        log.info("总数为："+aLong);
    }
}