添加依赖。

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.17</version>
        </dependency>

添加配置文件 config.MyDataSourceConfig.java

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.support.http.StatViewServlet;
import com.alibaba.druid.support.http.WebStatFilter;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;
import java.sql.SQLException;
import java.util.Arrays;


@Configuration
public class MyDataSourceConfig {

    // 默认的自动配置是判断容器中没有才会配@ConditionalOnMissingBean(DataSource.class)

    @ConfigurationProperties("spring.datasource")
    @Bean
    public DataSource dataSource() throws SQLException {
        DruidDataSource druidDataSource = new DruidDataSource();

//        druidDataSource.setUrl();
//        druidDataSource.setUsername();
//        druidDataSource.setPassword();
        //加入监控功能
          druidDataSource.setFilters("stat,wall");

//        druidDataSource.setMaxActive(10);
        return druidDataSource;
    }

    @Bean
    public ServletRegistrationBean statViewServlet(){
        StatViewServlet statViewServlet = new StatViewServlet();
        ServletRegistrationBean<StatViewServlet> registrationBean = new ServletRegistrationBean<>(statViewServlet, "/druid/*");

        registrationBean.addInitParameter("loginUsername","admin");
        registrationBean.addInitParameter("loginPassword","123456");


        return registrationBean;
    }

    @Bean
    public FilterRegistrationBean webStatFilter(){
        WebStatFilter webStatFilter = new WebStatFilter();

        FilterRegistrationBean<WebStatFilter> filterRegistrationBean = new FilterRegistrationBean<>(webStatFilter);
        filterRegistrationBean.setUrlPatterns(Arrays.asList("/*"));
        filterRegistrationBean.addInitParameter("exclusions","*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*");

        return filterRegistrationBean;
    }
}

测试类

    @Autowired
    JdbcTemplate jdbcTemplate;

    @ResponseBody
    @GetMapping("/sql")
    public String queryFromDb(){
        Long aLong = jdbcTemplate.queryForObject("select count(*) from user", Long.class);
        return aLong.toString();
    }