1.创建springboot项目并引入依赖

<dependencies>
        <!--引入jdbc驱动-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!--引入mysql-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <!--引入druid数据源-->
        <!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.8</version>
        </dependency>
        <!--日志-->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>

    </dependencies>

2.连接数据库和配置druid

在application.yml中配置连接数据库的4要素和用type指定druid连接池，注意，整合druid一定要配置type属性。
Springboot在整合jdbc的时候，SpringBoot2.0之前默认使用的是tomcat连接池。2.0以后默认使用Hikari连接池。也就是说在配置数据库的基本4要素的时候spring.datasource.driver-class-name配不配都可以，不配使用默认的，配了的话使用你自己配置的。
注意:使用druid的一些属性时，springboot并没有对应的属性，所以需要我们自己手动编写配置文件。

#数据库4要素配置
spring:
  datasource:
    username: root
    password: 123456
    url: jdbc:mysql://localhost/springboot-jdbc?useUnicode=true&characterEncoding=utf-8&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC
    driver-class-name: com.mysql.jdbc.Driver
    type: com.alibaba.druid.pool.DruidDataSource

#driud连接池的其他配置
#DataSourceProperties没有以下这些属性，所以要自己手动编写配置文件
    initialSize: 5
    minIdle: 5
    maxActive: 20
    maxWait: 60000
    timeBetweenEvictionRunsMillis: 60000
    minEvictableIdleTimeMillis: 300000
    validationQuery: SELECT 1 FROM DUAL
    testWhileIdle: true
    testOnBorrow: false
    testOnReturn: false
    poolPreparedStatements: true
    #   配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙
    filters: stat,wall,log4j
    maxPoolPreparedStatementPerConnectionSize: 20
    useGlobalDataSourceStat: true
    connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500

3.手动编写配置文件并配置druid的监控

创建DruidConfig配置类

@Configuration
public class DruidConfig {

    @ConfigurationProperties(prefix = "spring.datasource")
    @Bean
    public DataSource druid(){
        return  new DruidDataSource();
    }

    //配置Druid的监控
    //1、配置一个管理后台的Servlet
    @Bean
    public ServletRegistrationBean statViewServlet(){
        ServletRegistrationBean bean = new ServletRegistrationBean(new StatViewServlet(), "/druid/*");
        Map<String,String> initParams = new HashMap<>();

        initParams.put("loginUsername","admin");
        initParams.put("loginPassword","123456");
        initParams.put("allow","");//默认就是允许所有访问
        initParams.put("deny","192.168.15.21");

        bean.setInitParameters(initParams);
        return bean;
    }


    //2、配置一个web监控的filter
    @Bean
    public FilterRegistrationBean webStatFilter(){
        FilterRegistrationBean bean = new FilterRegistrationBean();
        bean.setFilter(new WebStatFilter());

        Map<String,String> initParams = new HashMap<>();
        initParams.put("exclusions","*.js,*.css,/druid/*");

        bean.setInitParameters(initParams);

        bean.setUrlPatterns(Arrays.asList("/*"));

        return  bean;
    }
}

4.测试能不能拿到连接对象

在springboot的测试类中测试DataSource对象

package cn.hzu.springboot_jdbc;

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;

@SpringBootTest
class SpringbootJdbcApplicationTests {

    @Autowired
    DataSource dataSource;

    @Test
    public void contextLoads() throws SQLException {
        //org.apache.tomcat.jdbc.pool.DataSource
        System.out.println(dataSource.getClass());

        Connection connection = dataSource.getConnection();
        System.out.println(connection);
        connection.close();

    }
}

输出结果

5.启动springboot应用查看druid的监控

成功访问

补充说明，上面要引入了log4j依赖。否则会报找不到log4j找不到异常
原因是我给druid配置的filter中有log4j.而我的项目中没有使用log4j的依赖导致的.可以log4j的filter去掉。这里就不去掉了。日志包这块个人感觉比较复杂，需要用中间包替换。我得再研究研究。