Alibaba Druid

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Druid is a high-performance database connection pool and SQL parser open-sourced by Alibaba. It deeply integrates JDBC connection pooling, SQL parsing and analysis, security protection, and monitoring statistics into one package, making it one of the most comprehensive database middleware solutions in the Java ecosystem.

Key Features

Capability	Description
JDBC Connection Pool	High-performance, monitorable pool implementation DruidDataSource with connection warm-up, PSCache, KeepAlive and more
SQL Parser	Full parser for 30 SQL dialects, generating AST (Abstract Syntax Tree) with support for formatting, rewriting and analysis
SQL Firewall	AST-based WallFilter for SQL injection protection, blocking dangerous operations
Monitoring & Stats	Built-in StatFilter for real-time SQL execution statistics, connection pool status, and Web monitoring console
Filter Extension	Pluggable Filter-Chain architecture supporting logging, encryption, statistics and custom extensions
Spring Boot Integration	Starters for Spring Boot 2.x / 3.x / 4.x with auto-configuration
High Availability	HighAvailableDataSource supporting multi-datasource load balancing, health checks and failover

Quick Start

Maven Dependency

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.2.24</version>
</dependency>

Spring Boot (Recommended)

Choose the starter matching your Spring Boot version:

Spring Boot Version	Starter
2.x	druid-spring-boot-starter
3.x	druid-spring-boot-3-starter
4.x	druid-spring-boot-4-starter

<!-- Spring Boot 3.x example -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-3-starter</artifactId>
    <version>1.2.24</version>
</dependency>

# application.yml
spring:
  datasource:
    url: jdbc:mysql://localhost:3306/mydb
    username: root
    password: password
    druid:
      initial-size: 5
      max-active: 20
      min-idle: 5
      max-wait: 60000
      filter:
        stat:
          enabled: true
          log-slow-sql: true
          slow-sql-millis: 2000
        wall:
          enabled: true

Direct DruidDataSource Usage

DruidDataSource dataSource = new DruidDataSource();
dataSource.setUrl("jdbc:mysql://localhost:3306/mydb");
dataSource.setUsername("root");
dataSource.setPassword("password");
dataSource.setInitialSize(5);
dataSource.setMaxActive(20);
dataSource.setMinIdle(5);
dataSource.init();

try (Connection conn = dataSource.getConnection()) {
    // execute SQL
}

SQL Parser

// Parse SQL
String sql = "SELECT id, name FROM users WHERE age > 18 ORDER BY name";
List<SQLStatement> stmts = SQLUtils.parseStatements(sql, DbType.mysql);

// Format SQL
String formatted = SQLUtils.format(sql, DbType.mysql);

// Extract schema information
SchemaStatVisitor visitor = SQLUtils.createSchemaStatVisitor(DbType.mysql);
stmts.get(0).accept(visitor);
System.out.println("Tables: " + visitor.getTables());
System.out.println("Columns: " + visitor.getColumns());

Project Modules

druid/
├── core/                           # Core library (pool, SQL parser, security, monitoring)
├── druid-spring-boot-starter/      # Spring Boot 2.x auto-configuration
├── druid-spring-boot-3-starter/    # Spring Boot 3.x auto-configuration
├── druid-spring-boot-4-starter/    # Spring Boot 4.x auto-configuration
├── druid-wrapper/                  # Wrapper utilities
├── druid-admin/                    # Cluster monitoring admin
└── doc/                            # Documentation

SQL Dialect Support

The Druid SQL parser supports 30 database dialects, each with full Lexer, Parser, AST and Visitor implementations:

Category	Supported Databases
Major RDBMS	MySQL, PostgreSQL, Oracle, SQL Server, DB2, H2, Informix
Chinese Databases	Dameng (DM), Oscar, GaussDB
Analytical / MPP	ClickHouse, Doris, StarRocks, Teradata, Redshift
Cloud / Data Warehouse	BigQuery, Snowflake, Synapse, Hologres, ODPS (MaxCompute)
Compute Engines	Hive, Spark, Presto, Impala, Athena, Blink, Databricks
Other	Phoenix, SuperSQL, Transact-SQL

Documentation

Document	Description
Architecture Overview	System architecture and core component interactions
Connection Pool Guide	DruidDataSource configuration, tuning and best practices
SQL Parser Guide	SQL parsing, formatting, rewriting and dialect extensions
SQL Dialect Support	Complete dialect support matrix and per-dialect features
Filter Mechanism	Filter-Chain architecture and custom Filter development
SQL Firewall	WallFilter configuration and SQL security
Monitoring & Statistics	StatFilter and Web monitoring console
High Availability	HighAvailableDataSource configuration and usage
Spring Boot Integration	Spring Boot Starter configuration guide
Wiki	FAQ and additional documentation

Building from Source

git clone https://github.com/alibaba/druid.git
cd druid
mvn clean install

Requirements: Java 8+ JDK, Apache Maven 3.6+

Contributing

Contributions are welcome! Please read the Contributing Guide for details.

Security

Please do not report security vulnerabilities through public issues. See Security Policy.

License

Druid is open-sourced under Apache License 2.0.