Druid 是开源平台上一个数据库连接池实现，具备日志监控功能

Druid 可以很好的监控 DB 连接池和 SQL 的执行情况，天生就是针对监控而生的 DB 连接池

Maven 仓库

pom.xml 文件导入 Durid 的 jar 包

        <!-- Druid依赖 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.2.23</version>
        </dependency>

application.yml 文件：

spring.datasource.type: com.alibaba.druid.pool.DruidDataSource

指定 DruidDataSource 连接池

spring:
  datasource:
    username: root
    password: root
    url: jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
    driver-class-name: com.mysql.cj.jdbc.Driver
    type: com.alibaba.druid.pool.DruidDataSource

测试类：

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

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

@SpringBootTest
class JdbcApplicationTests {

    @Autowired
    DataSource dataSource;

    @Test
    void contextLoads() throws SQLException {
        //查看默认数据源
        System.out.println(dataSource.getClass());

        //获得数据库连接
        Connection connection = dataSource.getConnection();
        System.out.println(connection);

        //关闭
        connection.close();
    }
}

运行，查看结果：数据源是 Druid

application.yml 文件：

druid 数据源配置

stat：监控统计、log4j：日志记录、wall：防御 sql 注入

spring:
  datasource:
    username: root
    password: root
    url: jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
    driver-class-name: com.mysql.cj.jdbc.Driver
    type: com.alibaba.druid.pool.DruidDataSource

    #SpringBoot默认不注入这些属性，需要自己绑定
    #druid数据源专有配置
    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

    #filters配置监控统计拦截
    #stat：监控统计  log4j：日志记录  wall：防御sql注入
    filters: stat,wall,log4j
    maxPoolPreparedStatementPerConnectionSize: 20
    useGlobalDataSourceStat: true
    connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500

pom.xml 导入 Log4j 依赖：

        <!-- Log4j依赖 -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>

DruidConfig 配置类：

@ConfigurationProperties(prefix = "spring.datasource")  绑定 yaml

后台监控 ServletRegistrationBean

SpringBoot 内置了 Servlet 容器，所以没有 web.xml，用 ServletRegistrationBean 代替

package com.demo.config;

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.support.http.StatViewServlet;
import com.alibaba.druid.support.jakarta.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.util.HashMap;

@Configuration
public class DruidConfig {

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

    //后台监控ServletRegistrationBean
    //SpringBoot内置了Servlet容器，所以没有web.xml，用ServletRegistrationBean代替
    @Bean
    public ServletRegistrationBean statViewServlet(){
        ServletRegistrationBean<StatViewServlet> bean = new ServletRegistrationBean<>(new StatViewServlet(), "/druid/*");

        HashMap<String,String> initParameters = new HashMap<>();

        //增加配置
        initParameters.put("loginUsername","admin");
        initParameters.put("loginPassword","123456");

        bean.setInitParameters(initParameters); //设置初始化参数
        return bean;
    }

    //filter过滤器
    @Bean
    public FilterRegistrationBean webStatFilter(){
        FilterRegistrationBean bean = new FilterRegistrationBean();
        bean.setFilter(new WebStatFilter());

        HashMap<String,String> initParameters = new HashMap<>();

        //exclusions排除，不进行统计
        initParameters.put("exclusions","*.js,*.css,/druid/*");

        bean.setInitParameters(initParameters);
        return bean;
    }
}