Build a Java 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>4.6.0-yb-6</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 YCQL.
- 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>4.6.0-yb-6</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