Java JDBC Connection to PostgreSQL Example

A JDBC example to show you how to connect to a PostgreSQL database with a JDBC driver.

Learn a complete JDBC tutorial at https://www.javaguides.net/p/jdbc-tutorial.html.

Download PostgreSQL JDBC Driver

Visit http://jdbc.postgresql.org/download.html to download the latest PostgreSQL JDBC Driver.

Maven

The PostgreSQL JDBC driver is available in the Maven central repository.
<dependency>
 <groupId>org.postgresql</groupId>
 <artifactId>postgresql</artifactId>
 <version>42.2.5</version>
</dependency>

JDBC Connection to PostgreSQL Example

import java.math.BigDecimal;
import java.time.LocalDateTime;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;

public class JDBCExample2 {

    public static void main(String[] args) {

        List < Employee > result = new ArrayList < > ();

        String SQL_SELECT = "Select * from EMPLOYEE";

        // auto close connection and preparedStatement
        try (Connection conn = DriverManager.getConnection(
            "jdbc:postgresql://127.0.0.1:5432/test", "postgres", "password"); PreparedStatement preparedStatement = conn.prepareStatement(SQL_SELECT)) {

            ResultSet resultSet = preparedStatement.executeQuery();

            while (resultSet.next()) {

                long id = resultSet.getLong("ID");
                String name = resultSet.getString("NAME");
                BigDecimal salary = resultSet.getBigDecimal("SALARY");
                Timestamp createdDate = resultSet.getTimestamp("CREATED_DATE");

                Employee obj = new Employee();
                obj.setId(id);
                obj.setName(name);
                obj.setSalary(salary);
                // Timestamp -> LocalDateTime
                obj.setCreatedDate(createdDate.toLocalDateTime());

                result.add(obj);

            }
            result.forEach(x - > System.out.println(x));

        } catch (SQLException e) {
            System.err.format("SQL State: %s\n%s", e.getSQLState(), e.getMessage());
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

}

class Employee {

    private Long id;
    private String name;
    private BigDecimal salary;
    private LocalDateTime createdDate;

    //...
}
Table definition.
CREATE TABLE EMPLOYEE
(
    ID serial,
    NAME varchar(100) NOT NULL,
    SALARY numeric(15, 2) NOT NULL,
    CREATED_DATE timestamp with time zone NOT NULL DEFAULT CURRENT_TIMESTAMP
    PRIMARY KEY (ID)
);

References



Comments

Post a Comment