Build a Java application

Prerequisites

This tutorial assumes that:

  • YugabyteDB is up and running. If you are new to YugabyteDB, you can download, install, and have YugabyteDB up and running within five minutes 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 within 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