🐘
How to connect to PostgreSQL with Java
2017. August 1.
- Download and start PostgreSQL from https://www.postgresql.org/
- Add the
postgresql
dependency in yourbuild.gradle
file (compile group: 'postgresql', name: 'postgresql', version: '9.0-801.jdbc4'
) - You are ready to connect to PostgreSQL with for example the following program:
package hello;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class HelloWorld {
private final String url = "jdbc:postgresql://localhost:5432/postgres";
private final String username = "postgres";
private final String password = "your-password";
public Connection connect() {
try {
Class.forName("org.postgresql.Driver");
} catch (ClassNotFoundException e ) {
System.out.println("Where is your PostgreSQL JDBC Driver? "
+ "Include in your library path!");
e.printStackTrace();
}
Connection c = null;
try {
c = DriverManager.getConnection(url, username, password);
} catch (SQLException e) {
System.out.println("Connection Failed! Check output console");
e.printStackTrace();
}
if (c != null) {
System.out.println("You made it, take control your database now!");
return c;
} else {
System.out.println("Failed to make connection!");
return null;
}
}
public static void main(String[] args) {
HelloWorld hello = new HelloWorld();
hello.connect();
}
}
Additionally, this is how we can query the database:
ResultSet rs;
try {
rs = st.executeQuery("SELECT * from animals");
while (rs.next()) {
System.out.print("Column returned 1:");
System.out.print(rs.getString(1));
}
rs.close();
st.close();
} catch (SQLException e ) {
System.out.println("Resultset creation failed!");
e.printStackTrace();
}