gem-hunter

Table of Contents

• About The project
• Client Features
• Important
• Installation
• Client V2
  • Artifacts
  • Examples
• Client V1
  • Artifacts
  • Examples
• Contributing

This is the repository for the Java Client and JDBC Driver for the ClickHouse database, supported by the ClickHouse team.

The Java Client is the core component that provides an API to interact with the database via HTTP Protocol. The JDBC driver component implements the JDBC specification and communicates with ClickHouse using the Java Client API.

The client and driver work with both ClickHouse Cloud and self-hosted ClickHouse. You can start a free Cloud trial or install ClickHouse locally.

Historically, there are two versions of both components. The previous version of the Java client required a significant rewrite, so we decided to create a new one, client-v2, not to disturb anyone's work and to give time for migration. The JDBC driver also required changes to be compatible with the new client and comply more with JDBC specs, and we created jdbc-v2. This component will replace an old version (to keep the artifact name).

Name	Client V2	Client V1	Comments
Http Connection	✔	✔
Http Compression (LZ4)	✔	✔
Server Response Compression - LZ4	✔	✔
Client Request Compression - LZ4	✔	✔
HTTPS	✔	✔
Client SSL Cert (mTLS)	✔	✔
Http Proxy with Authentication	✔	✔
Java Object SerDe	✔	✗
Connection Pool	✔	✔	Apache HTTP Client only
Named Parameters	✔	✔
Retry on failure	✔	✔
Failover	✗	✔
Load-balancing	✗	✔
Server auto-discovery	✗	✔
Log Comment	✔	✔
Session Roles	✔	✔
SSL Client Authentication	✔	✔
Session timezone	✔	✔

We are going to retire some JDBC artifacts (actually only classifiers) in 0.9.0. Here is the list:

Artifact	Classifier	Comments
clickhouse-jdbc	shaded	Use one with all classifier instead
clickhouse-jdbc	http
clickhouse-jdbc	shaded-all	Use one with all classifier instead

Artifact com.clickhouse:clickhouse-jdbc remains untouched. Artifact com.clickhouse:clickhouse-jdbc:0.9.0:all will contain all required classes.

Component	Version	Comment
ClickHouse Java v1	TBC	We'll be deprecating Java v1 in 2025

Releases: Maven Central (web site https://mvnrepository.com/artifact/com.clickhouse)

Nightly Builds: https://s01.oss.sonatype.org/content/repositories/snapshots/com/clickhouse/

Component	Maven Central Link	Javadoc Link	Documentation Link
ClickHouse Java Client V2			docs

Begin-with Usage Examples

Spring Demo Service

Component	Maven Central Link	Javadoc Link	Documentation Link
ClickHouse JDBC Driver			docs

See JDBC examples

Component	Maven Central Link	Javadoc Link	Documentation Link
ClickHouse R2DBC Driver			docs

Component	Maven Central Link	Javadoc Link
ClickHouse Java Unified Client
ClickHouse Java HTTP Client

• All projects in this repo are tested with all active LTS versions of ClickHouse.
• Support policy
• We recommend to upgrade client continuously to not miss security fixes and new improvements
  • If you have an issue with migration - create and issue and we will respond!

Please see our contributing guide.