JDBC- postgres, connection refused

Question

This is my first time using java to access databases, so I probably have a simple mistake here, but when I go to retrieve my connection from a remote database I have access to, I get a connection refused.

Here's the code in question:

String url = "jdbc:postgresql:url.isformatted.like.this/database";

try {
    conn = DriverManager.getConnection(url, "username", "password");
} catch (SQLException e) {
    e.printStackTrace();
    System.exit(1);
}

(user/pass and database url removed for privacy sake)

The problem couldn't be credentials or the URL itself, as I use it to manually log in from the same box successfully using psql. I'm thinking it's probably the formatting of the URL, but I couldn't find any examples of psql being used on a remote address (they were all local host kinda things)

Answer 1

According to http://www.petefreitag.com/articles/jdbc_urls/ valid urls are

jdbc:postgresql:database
jdbc:postgresql://host/database
jdbc:postgresql://host:port/database
jdbc:postgresql://host:port/database?user=userName&password=pass
jdbc:postgresql://host:port/database?charSet=LATIN1&compatible=7.2

Do you have the // before the host?

Answer 2

I would agree with @Jonathan about having the PostgreSQL JDBC jar library on you classpath: here is what I used:

private static final String TABLE_NAME = "tablenamegoeshere";
private static final String DRIVER = "org.postgresql.Driver";
private static final String URL = "jdbc:postgresql://url.for.database/DatabaseName";
private static final String USERNAME = "yourusername";
private static final String PASSWORD = "yourpassword";


private static Connection getConnection() throws Exception {
  Class.forName(DRIVER);
  Connection conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
  return conn;
}

Answer 3

I just looked ad my code which connects to a PostgreSQL database, and it looks like this:

DriverManager.getConnection(String.format("jdbc:postgresql://%s/%s", server, dbName), userName, password);

Also, make sure you're loading the PostgreSQL database driver before trying to connect:

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

and that the PostgreSQL JDBC Jar library is on your classpath.