Connect an application

Maven

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

 <dependency>
   <groupId>com.yugabyte</groupId>
   <artifactId>java-driver-core</artifactId>
   <version>4.15.0-yb-1</version>
 </dependency>

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>
  <properties>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>

  <dependencies>
    <dependency>
      <groupId>com.yugabyte</groupId>
      <artifactId>java-driver-core</artifactId>
      <version>4.15.0-yb-1</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.net.InetSocketAddress;
import java.util.List;
import com.datastax.oss.driver.api.core.CqlSession;
import com.datastax.oss.driver.api.core.cql.ResultSet;
import com.datastax.oss.driver.api.core.cql.Row;
public class YBCqlHelloWorld {
    public static void main(String[] args) {
        try {
            // Create a YCQL client.
            CqlSession session = CqlSession
                .builder()
                .addContactPoint(new InetSocketAddress("127.0.0.1", 9042))
                .withLocalDatacenter("datacenter1")
                .build();
            // Create keyspace 'ybdemo' if it does not exist.
            String createKeyspace = "CREATE KEYSPACE IF NOT EXISTS ybdemo;";
            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);";
            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');";
            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();
        } 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