Integrating Alibaba Druid Connection Pool with Spring Boot: Configuration and Monitoring Guide

1. Introduction

Druid is an open‑source JDBC connection pool from Alibaba, praised for its monitoring capabilities, performance, and extensibility, and is widely used in production environments.

It consists of three main parts: DruidDriver (provides a filter‑chain plugin system), DruidDataSource (the high‑efficiency connection pool), and SQLParser (SQL syntax analysis).

2. Monitoring Features

Druid includes a built‑in StatFilter that records database access performance, such as execution time, result set hold time, row counts, error counts, and error stack traces. It also aggregates SQL execution time into interval distributions, helping identify slow queries.

The pool statistics cover physical connection creation/destruction, logical connection acquisition/release, wait counts, and PSCache hit rates.

3. Password Encryption

Both DruidDriver and DruidDataSource support the PasswordCallback interface, allowing encrypted passwords instead of plain text in configuration files.

4. SQLParser

Druid’s hand‑written high‑performance SQL parser supports MySQL, Oracle, PostgreSQL, and SQL‑92, enabling visitor‑pattern AST analysis, SQL injection defense (WallFilter), SQL merging, formatting, and sharding.

5. Dependency Integration

Add the Spring Boot starter for Druid in pom.xml :

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.1.21</version>
</dependency>

Configure the datasource in application.yaml (example shown below):

spring:
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    druid:
      driver-class-name: com.mysql.cj.jdbc.Driver
      url: jdbc:mysql://127.0.0.1:3306/ds0?characterEncoding=utf-8&useSSL=false
      username: root
      password: 111111
      initial-size: 5
      min-idle: 5
      max-active: 20
      max-wait: 60000
      time-between-eviction-runs-millis: 60000
      min-evictable-idle-time-millis: 300000
      validation-query: SELECT 'x'
      test-while-idle: true
      test-on-borrow: false
      test-on-return: false
      pool-prepared-statements: false
      max-pool-prepared-statement-per-connection-size: -1
      use-global-data-source-stat: true
      connection-properties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
      filters: stat,wall,log4j

6. Detailed Configuration Options

The table below summarizes the most common Druid properties, their default values, and descriptions (e.g., maxActive – maximum pool size, validationQuery – SQL used to test connection health, filters – plugin aliases such as stat , wall , log4j ).

7. Available Filters

Common filter aliases include:

stat – com.alibaba.druid.filter.stat.StatFilter

mergeStat – com.alibaba.druid.filter.stat.MergeStatFilter

encoding – com.alibaba.druid.filter.encoding.EncodingConvertFilter

log4j – com.alibaba.druid.filter.logging.Log4jFilter

wall – com.alibaba.druid.wall.WallFilter

8. Druid Monitoring Bean Configuration

Register the monitoring servlet and web filter via Java configuration:

@Bean
public ServletRegistrationBean druidServlet() {
    ServletRegistrationBean bean = new ServletRegistrationBean();
    bean.setServlet(new StatViewServlet());
    bean.addUrlMappings("/druid/*");
    Map
params = new HashMap<>();
    params.put("loginUsername", "admin");
    params.put("loginPassword", "admin");
    params.put("resetEnable", "false");
    params.put("allow", ""); // allow all IPs
    bean.setInitParameters(params);
    return bean;
}

@Bean
public FilterRegistrationBean filterRegistrationBean() {
    FilterRegistrationBean bean = new FilterRegistrationBean();
    bean.setFilter(new WebStatFilter());
    bean.addUrlPatterns("/*");
    bean.addInitParameter("exclusions", "*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*");
    return bean;
}

Alternatively, configure the same settings in application.properties :

# Druid monitoring login
spring.datasource.druid.stat-view-servlet.login-username=admin
spring.datasource.druid.stat-view-servlet.login-password=admin

# Enable slow‑SQL logging
spring.datasource.druid.filter.stat.log-slow-sql=true
spring.datasource.druid.filter.stat.slow-sql-millis=2000

# Exclude static resources from web‑stat filter
spring.datasource.druid.web-stat-filter.exclusions=*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*

9. Accessing the Monitoring Console

Start the Spring Boot application and open http://127.0.0.1:8090/druid/sql.html . Log in with the configured username and password (default admin/admin ) to view real‑time statistics such as JDK version, driver info, JVM metrics, datasource details, SQL execution counts, time distribution, and more.

10. Source Code

The example project is available at:

https://github.com/aalansehaiyang/spring-boot-bulking
Module: spring-boot-bulking-druid