Build a Java application

Prerequisites

This tutorial assumes that:

  • YugabyteDB is up and running. Download and install YugabyteDB by following the steps in Quick start.
  • Java Development Kit (JDK) 1.8, or later, is installed. JDK installers for Linux and macOS can be downloaded from OpenJDK, AdoptOpenJDK, or Azul Systems.
  • Apache Maven 3.3 or later, is installed.

Create and configure the Java project

  1. Create a project called "MySample".

    $ mvn archetype:generate \
    -DgroupId=com.yugabyte \
    -DartifactId=MySample \
    -DarchetypeArtifactId=maven-archetype-quickstart \
    -DinteractiveMode=false

$ cd MySample

  2. Open the pom.xml file in a text editor.

  3. Add the following below the <url> element.

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

  4. Add the following in the <dependencies> element.

    <dependency>
  <groupId>org.postgresql</groupId>
  <artifactId>postgresql</artifactId>
  <version>42.2.14</version>
</dependency>

    Your pom.xml file should now be similar to the following:

    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.yugabyte</groupId>
  <artifactId>MySample</artifactId>
  <packaging>jar</packaging>
  <version>1.0-SNAPSHOT</version>
  <name>MySample</name>
  <url>http://maven.apache.org</url>
  <properties>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.postgresql</groupId>
      <artifactId>postgresql</artifactId>
      <version>42.2.14</version>
    </dependency>
  </dependencies>
</project>

  5. Save and close pom.xml.

  6. Install the added dependency.

    $ mvn install

Create the sample Java application

  1. Copy the following Java code to a new file named src/main/java/com/yugabyte/HelloSqlApp.java:

    package com.yugabyte;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class HelloSqlApp {
  public static void main(String[] args) throws ClassNotFoundException, SQLException {
    Class.forName("org.postgresql.Driver");
    Connection conn = DriverManager.getConnection("jdbc:postgresql://localhost:5433/yugabyte",
                                                  "yugabyte", "yugabyte");
    Statement stmt = conn.createStatement();
    try {
        System.out.println("Connected to the PostgreSQL server successfully.");
        stmt.execute("DROP TABLE IF EXISTS employee");
        stmt.execute("CREATE TABLE IF NOT EXISTS employee" +
                    "  (id int primary key, name varchar, age int, language text)");
        System.out.println("Created table employee");

        String insertStr = "INSERT INTO employee VALUES (1, 'John', 35, 'Java')";
        stmt.execute(insertStr);
        System.out.println("EXEC: " + insertStr);

        ResultSet rs = stmt.executeQuery("select * from employee");
        while (rs.next()) {
          System.out.println(String.format("Query returned: name = %s, age = %s, language = %s",
                                          rs.getString(2), rs.getString(3), rs.getString(4)));
        }
    } catch (SQLException e) {
      System.err.println(e.getMessage());
    }
  }
}

  2. Run your new program.

    $ mvn -q package exec:java -DskipTests -Dexec.mainClass=com.yugabyte.HelloSqlApp

    You should see the following as the output:

    Connected to the PostgreSQL server successfully.
Created table employee
Inserted data: INSERT INTO employee (id, name, age, language) VALUES (1, 'John', 35, 'Java');
Query returned: name=John, age=35, language: Java