# nebula-java
**Repository Path**: mayjean/nebula-java
## Basic Information
- **Project Name**: nebula-java
- **Description**: Client API and data importer of Nebula Graph in Java
- **Primary Language**: Java
- **License**: Apache-2.0
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No
## Statistics
- **Stars**: 0
- **Forks**: 1
- **Created**: 2024-08-22
- **Last Updated**: 2025-03-03
## Categories & Tags
**Categories**: Uncategorized
**Tags**: None
## README
# nebula-java
[](https://github.com/vesoft-inc/nebula-java/blob/master/LICENSE)
[](https://github.com/vesoft-inc/nebula-java/releases)
[](https://github.com/vesoft-inc/nebula-java/releases)
[](https://codecov.io/gh/vesoft-inc/nebula-java)
Nebula Java is a Java client for developers to connect their projects to Nebula Graph.
Please be noted that [nebula-JDBC](https://github.com/vesoft-inc/nebula-jdbc)(based on nebula-java)
is the JDBC implementing for nebula graph.
> **NOTE**: Nebula Java is not thread-safe.
## Two main branches of this repository
In this repository, you can find two branches for the source code of Nebula Java of different
versions.
### The master branch
The master branch is for Nebula Java v2.0, which works with Nebula Graph v2.0 nightly.
This README file provides Java developers with instructions on how to connect to Nebula Graph v2.0.
### The v1.0 branch
In the v1.0 branch, you can find source code of these:
- Nebula Java v1.0, which works with Nebula Graph v1.1.0 and earlier versions only.
- Nebula Graph Exchange, Nebula Spark Connector, Nebula Flink Connector, and nebula-algorithm.
For more information,
see [README of v1.0](https://github.com/vesoft-inc/nebula-java/blob/v1.0/README.md).
### The v2.0.0-rc branch
The v2.0.0-rc branch works with Nebula Graph v2.0.0-beta and v2.0.0-rc1, but not for the latest
nightly Nebula Graph.
## Prerequisites
To use this Java client, do a check of these:
- Java 8 or a later version is installed.
- Nebula Graph is deployed. For more information,
see [Deployment and installation of Nebula Graph](https://docs.nebula-graph.io/master/4.deployment-and-installation/1.resource-preparations/ "Click to go to Nebula Graph website").
## Modify pom.xml
If you use Maven to manage your project, add the following dependency to your `pom.xml` file.
Replace `3.0-SNAPSHOT` with an appropriate Nebula Java version.
For more versions, visit [releases](https://github.com/vesoft-inc/nebula-java/releases).
```xml
com.vesoft
client
3.0-SNAPSHOT
```
There are the version correspondence between client and Nebula:
| Client version | Nebula Version |
|:--------------:|:-----------------:|
| 1.0.0 | 1.0.0 |
| 1.0.1 | 1.1.0,1.2.0 |
| 1.1.0 | 1.1.0,1.2.0 |
| 1.2.0 | 1.1.0,1.2.0,1.2.1 |
| 2.0.0-beta | 2.0.0-beta |
| 2.0.0-rc1 | 2.0.0-rc1 |
| 2.0.0 | 2.0.0,2.0.1 |
| 2.0.1 | 2.0.0,2.0.1 |
| 2.5.0 | 2.5.0,2.5.1 |
| 2.6.0 | 2.6.0,2.6.1 |
| 2.6.1 | 2.6.0,2.6.1 |
| 3.x | 3.x |
| 3.0-SNAPSHOT | nightly |
## Graph client example
To connect to the `nebula-graphd` process of Nebula Graph:
```java
NebulaPoolConfig nebulaPoolConfig = new NebulaPoolConfig();
nebulaPoolConfig.setMaxConnSize(10);
List addresses = Arrays.asList(new HostAddress("127.0.0.1", 9669), new HostAddress("127.0.0.1", 9670));
NebulaPool pool = new NebulaPool();
pool.init(addresses, nebulaPoolConfig);
Session session = pool.getSession("root", "nebula", false);
session.execute("SHOW HOSTS;");
session.release();
pool.close();
```
## Graph SessionPool example
To use SessionPool, you must config the space to connect for SessionPool.
The SessionPool is thread-safe, and support retry(release old session and get available session from
SessionPool) for both connection error, session error and
execution error(caused by bad storaged server), and the retry mechanism needs users to config
retryTimes and intervalTime between retrys.
And SessionPool maintains servers' status, can isolation broken graphd server and auto routing
restarted graphd server when you need to execute with new session， meaning your parallel is larger
than the idle session number in the session pool.
```java
List addresses = Arrays.asList(new HostAddress("127.0.0.1", 9669));
String spaceName = "test";
String user = "root";
String password = "nebula";
SessionPoolConfig sessionPoolConfig = new SessionPoolConfig(addresses, spaceName, user, password);
sessionPoolConfig.setRetryTimes(3);
sessionPoolConfig.setIntervalTime(1000);
SessionPool sessionPool = new SessionPool(sessionPoolConfig);
if (!sessionPool.init()) {
log.error("session pool init failed.");
return;
}
ResultSet resultSet;
try {
resultSet = sessionPool.execute("match (v:player) return v limit 1;");
System.out.println(resultSet.toString());
} catch (IOErrorException | ClientServerIncompatibleException | AuthFailedException | BindSpaceFailedException e) {
e.printStackTrace();
System.exit(1);
} finally {
sessionPool.close();
}
```