postgresql-demos/java/PostgresqlDemo.java

import java.sql.*;
import java.util.Properties;

import static java.lang.System.exit;

public class PostgresqlDemo {
    private Connection conn;

    private PostgresqlDemo() {
        String url = "jdbc:postgresql://localhost/databasename";
        Properties props = new Properties();
        props.setProperty("user", "bdd");
        props.setProperty("password", "bdd");
        try {
            conn = DriverManager.getConnection(url, props);
        }
        catch (SQLException e) {
            e.printStackTrace();
            exit(1);
        }
        try {
            Statement statement = conn.createStatement();
            ResultSet resultSet = statement.executeQuery("SELECT * FROM turista");
            ResultSetMetaData resultSetMetaData = resultSet.getMetaData();
            for (int i = 1; i <= resultSetMetaData.getColumnCount(); i++) {
                System.out.printf("%-20s", resultSetMetaData.getColumnName(i));
            }
            System.out.print("\n\n");
            while (resultSet.next()) {
                for (int i = 1; i <= resultSetMetaData.getColumnCount(); i++) {
                    Object object = resultSet.getObject(i);
                    System.out.printf("%-20s", object == null ? "NULL" : object.toString());
                }
                System.out.print("\n");
            }
            resultSet.close();
            statement.close();
        }
        catch (SQLException e) {
            e.printStackTrace();
        }
        try {
            conn.close();
        }
        catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        new PostgresqlDemo();
    }
}