firepation / nebula-java

Client API and data importer of Nebula Graph in Java

nebula-java

This guide provides instructions and options for connecting Nebula Graph for Java developer. However, Nebula Java is not not thread-safe.

Prerequisites

When developing with this Java driver, please use Java 8+. Depending on the version of Nebula Graph that you are connecting to, you will have to use a different version of this client.

Nebula version	Nebula Java version
1.0.0	1.0.0

Nebula Graph Java Driver

When using Maven, add dependency to your pom.xml file:

<dependency>
    <groupId>com.vesoft</groupId>
    <artifactId>client</artifactId>
    <version>1.0.0</version>
</dependency>

For more versions, please refer to releases.

Graph Client Example

Connect to the graphd:

GraphClient client = new GraphClientImpl("127.0.0.1", 3699);
client.setUser("user");
client.setPassword("password");
client.connect();

Use a space:

int code = client.switchSpace("space_test");

Execute a query:

int code = client.execute("CREATE TAG course(name string, credits int);");

If query executes successfully, 0 will be returned. For a more complete example, refer to Graph Java client example.

Storage Client

If you only use the interface of RPC, nothing to worry about.

If you want to directly use storage client to encode/decode, you need to use the jni interface. We have already package a libnebula_codec.so in the nebula-utils jar, but if it doesn't work in your environment, please compile the dynamic link library. And mvn install the jni jar in your local maven repo.

See more Storage Client Examples for how to scan edges and vertices from storage directly.

Meta Client

See Meta Client Example to access graph schemas.

FAQ

Q: Error occurs when building from the source code.

Failed to execute goal org.apache.maven.plugins:maven-gpg-plugin:1.6:sign (default) on project client: Exit code: 2 -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-gpg-plugin:1.6:sign (default) on project client: Exit code: 2

A: This means that you need to have a key to sign the jars

gpg --gen-key #generate your key pair
gpg --list-secret-keys #check if keys are generated successfully