Comprehensive Guide to Configuring Druid DataSource in Spring Boot

1. Basic Concepts

Druid is considered the best Java database connection pool, offering powerful monitoring and extensibility, and surpassing other pools such as HikariCP, C3P0, DBCP, and BoneCP.

It provides built‑in filters like stat for statistics, wall for SQL injection protection, and log4j2 for logging SQL statements.

2. Adding Dependencies

<!-- Alibaba Druid starter -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.1.23</version>
</dependency>
<!-- MySQL 8 driver -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>
<!-- Log4j2 starter -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-log4j2</artifactId>
</dependency>
<!-- MyBatis starter with Hikari exclusion -->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.1.3</version>
    <exclusions>
        <exclusion>
            <groupId>com.zaxxer</groupId>
            <artifactId>HikariCP</artifactId>
        </exclusion>
    </exclusions>
</dependency>

3. Configuring Properties

Configure the Druid datasource in application.yml , setting JDBC credentials, pool size, validation query, and enabling filters such as stat,wall,log4j2 . Also configure WebStatFilter for web request monitoring and StatViewServlet for the built‑in monitoring UI.

spring:
  datasource:
    druid:
      initial-size: 5
      minIdle: 10
      max-active: 20
      max-wait: 60000
      time-between-eviction-runs-millis: 2000
      min-evictable-idle-time-millis: 600000
      max-evictable-idle-time-millis: 900000
      validationQuery: select 1
      testWhileIdle: true
      testOnBorrow: false
      testOnReturn: false
      poolPreparedStatements: true
      maxOpenPreparedStatements: 20
      keepAlive: true
      aop-patterns: "com.springboot.template.dao.*"
      filters: stat,wall,log4j2
      web-stat-filter:
        enabled: true
        url-pattern: "/*"
        exclusions: "*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*"
        session-stat-enable: true
        session-stat-max-count: 1000
      stat-view-servlet:
        enabled: true
        url-pattern: /druid/*
        reset-enable: false
        login-username: root
        login-password: 123
        allow: 127.0.0.1

4. Monitoring Pages

After starting the application, access /druid/login.html to view the monitoring dashboard, which includes data source information, SQL execution statistics, URL access stats, Spring AOP monitoring, SQL firewall details, session monitoring, and a JSON API.

5. SQL Monitoring

Enable WebStatFilter to collect SQL execution time, request counts, and related database activity for each web request.

6. Slow SQL Logging

Configure the StatFilter with log-slow-sql: true and set slow-sql-millis (e.g., 2000 ms) to record slow queries in the logs.

7. Spring Monitoring

Add the spring-boot-starter-aop dependency and set spring.datasource.druid.aop-patterns to monitor method execution times via AOP.

8. Removing Druid Advertisement

Two approaches: (1) manually comment out the footer code in common.js inside the Druid JAR; (2) register a custom filter that intercepts the common.js request and strips the advertisement HTML using regex.

9. Accessing Druid Statistics Programmatically

Use DruidStatManagerFacade#getDataSourceStatDataList to retrieve datasource monitoring data, or expose it via a REST controller:

@RestController
@RequestMapping("/druid")
public class DruidStatController {
    @GetMapping("/stat")
    public Object druidStat() {
        return DruidStatManagerFacade.getInstance().getDataSourceStatDataList();
    }
}