Connect an application YCQL

YSQL
YCQL

YugabyteDB Java Driver for YCQL (3.10) is based on DataStax Java Driver 3.10 for YCQL with additional smart driver features.

YugabyteDB Aeon

To use the driver's partition-aware load balancing feature in a YugabyteDB Aeon cluster, applications must be deployed in a VPC that has been peered with the cluster VPC so that they have access to all nodes in the cluster. For more information, refer to Using YCQL drivers with YugabyteDB Aeon.

Maven

To build a sample Java application with the Yugabyte Java Driver for YCQL, add the following Maven dependency to your application:

   <dependencies>
    <dependency>
      <groupId>com.yugabyte</groupId>
      <artifactId>cassandra-driver-core</artifactId>
      <version>3.10.3-yb-2</version>
    </dependency>
  </dependencies>

Create the sample Java application

Prerequisites

This tutorial assumes that you have:

installed YugabyteDB, created a universe, and are able to interact with it using the YCQL shell. If not, follow the steps in Quick start.
installed JDK version 1.8 or later.
installed Maven 3.3 or later.

Create the project's POM

Create a file, named pom.xml, and then copy the following content into it. The Project Object Model (POM) includes configuration information required to build the project.

<?xml version="1.0"?>
<project
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
  xmlns="http://maven.apache.org/POM/4.0.0"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.yugabyte.sample.apps</groupId>
  <artifactId>hello-world</artifactId>
  <version>1.0</version>
  <packaging>jar</packaging>

  <dependencies>
    <dependency>
      <groupId>com.yugabyte</groupId>
      <artifactId>cassandra-driver-core</artifactId>
      <version>3.8.0-yb-5</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-dependency-plugin</artifactId>
        <version>2.1</version>
        <executions>
          <execution>
            <id>copy-dependencies</id>
            <phase>prepare-package</phase>
            <goals>
              <goal>copy-dependencies</goal>
            </goals>
            <configuration>
              <outputDirectory>${project.build.directory}/lib</outputDirectory>
              <overWriteReleases>true</overWriteReleases>
              <overWriteSnapshots>true</overWriteSnapshots>
              <overWriteIfNewer>true</overWriteIfNewer>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
</project>

Write a sample Java application

Create the appropriate directory structure as expected by Maven.

$ mkdir -p src/main/java/com/yugabyte/sample/apps

Copy the following contents into the file src/main/java/com/yugabyte/sample/apps/YBCqlHelloWorld.java.

package com.yugabyte.sample.apps;

import java.util.List;
import com.datastax.driver.core.Cluster;
import com.datastax.driver.core.ResultSet;
import com.datastax.driver.core.Row;
import com.datastax.driver.core.Session;

public class YBCqlHelloWorld {
  public static void main(String[] args) {
    try {
      // Create a Cassandra client.
      Cluster cluster = Cluster.builder()
                               .addContactPoint("127.0.0.1")
                               .build();
      Session session = cluster.connect();

      // Create keyspace 'ybdemo' if it does not exist.
      String createKeyspace = "CREATE KEYSPACE IF NOT EXISTS ybdemo;";
      ResultSet createKeyspaceResult = session.execute(createKeyspace);
      System.out.println("Created keyspace ybdemo");

      // Create table 'employee' if it does not exist.
      String createTable = "CREATE TABLE IF NOT EXISTS ybdemo.employee (id int PRIMARY KEY, " +
                                                                       "name varchar, " +
                                                                       "age int, " +
                                                                       "language varchar);";
      ResultSet createResult = session.execute(createTable);
      System.out.println("Created table employee");

      // Insert a row.
      String insert = "INSERT INTO ybdemo.employee (id, name, age, language)" +
                                          " VALUES (1, 'John', 35, 'Java');";
      ResultSet insertResult = session.execute(insert);
      System.out.println("Inserted data: " + insert);

      // Query the row and print out the result.
      String select = "SELECT name, age, language FROM ybdemo.employee WHERE id = 1;";
      ResultSet selectResult = session.execute(select);
      List<Row> rows = selectResult.all();
      String name = rows.get(0).getString(0);
      int age = rows.get(0).getInt(1);
      String language = rows.get(0).getString(2);
      System.out.println("Query returned " + rows.size() + " row: " +
                         "name=" + name + ", age=" + age + ", language: " + language);

      // Close the client.
      session.close();
      cluster.close();
    } catch (Exception e) {
        System.err.println("Error: " + e.getMessage());
    }
  }
}

Build the project

To build the project, run the following mvn package command.

$ mvn package

You should see a BUILD SUCCESS message.

Run the application

To use the application, run the following command.

$ java -cp "target/hello-world-1.0.jar:target/lib/*" com.yugabyte.sample.apps.YBCqlHelloWorld

You should see the following as the output.

Created keyspace ybdemo
Created table employee
Inserted data: INSERT INTO ybdemo.employee (id, name, age, language) VALUES (1, 'John', 35, 'Java');
Query returned 1 row: name=John, age=35, language: Java