import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

/*

* Author: Edwin Torres

* email: CoachEd@gmail.com

* Description: This program shows how to connect to a

* PostgreSQL database from Java.

*

*/

public class Main {

private Connection conn = null;

public static void main(String[] args) {

Main obj = new Main();

/* PostgreSQL server details (CHANGE THESE VALUES) */

String server = "127.0.0.1";

String database = "dbName";

String username = "user1";

String password = "pass1";

/** create the url string for the connection */

String url = "jdbc:postgresql://" + server + "/" + database;

/** establish the connection */

try {

/** register the database driver */

Class.forName("org.postgresql.Driver");

/** get the connection */

obj.setConn(DriverManager.getConnection(url, username, password));

} catch (ClassNotFoundException e) {

obj.setConn(null);

e.printStackTrace();

} catch (SQLException e) {

obj.setConn(null);

e.printStackTrace();

} catch (Exception e) {

obj.setConn(null);

e.printStackTrace();

}

/** use the connection */

if (obj.getConn() != null) {

obj.queryDatabase();

}

/** close the connection */

try {

if (obj.getConn() != null) {

obj.getConn().close();

obj.setConn(null);

}

} catch (SQLException e) {

e.printStackTrace();

}

}

public void queryDatabase() {

Statement stmt = null;

ResultSet rs = null;

try {

stmt = conn.createStatement();

String sql;

sql = "SELECT * FROM yourTable"; //CHANGE THIS

rs = stmt.executeQuery(sql);

while(rs.next()){

//display first column

System.out.println(rs.getString(1));

}

rs.close();

stmt.close();

} catch (SQLException e) {

stmt = null;

rs = null;

e.printStackTrace();

}

}

public Connection getConn() {

return conn;

}

public void setConn(Connection conn) {

this.conn = conn;

}

}