Establishing Connections from JDBC to Databases

JDBC for Oracle - Herong's Tutorial Examples

∟JDBC (Java Database Connectivity) Introduction

∟Establishing Connections from JDBC to Databases

This section provides some quick information on establishing connections from JDBC to databases.

JDBC API offers two different ways to establish a connection to the database server:

1. Using DrirverManager Class: DriverManager.getConnection(connection_url) - The driver manager passes the connection URL to all loaded JDBC drivers, hoping that one of them will recognize the URL and creates a connection. See sample code below:

   // Loading a JDBC driver
   Class.forName("acme.db.Driver");

   // Creating a connection
   String url = "jdbc:odbc:fred";
   Connection con = DriverManager.getConnection(url,"user","pass");

2. Using DataSource Object: ds.getConnection() - A DataSource object should be configured and registered with a JNDI (Java Naming and Directory Interface) directory service only once. When a connection is needed, the registered DataSource object can be retrieved back from JNDI. A connection can be then created from the retrieved DataSource object.

   // Registering a DataSource
   VendorDataSource vds = new VendorDataSource();
   vds.setServerName("my_database_server");
   vds.setDatabaseName("my_database");
   vds.setDescription("the data source for inventory and personnel");
   Context ctx = new InitialContext();
   ctx.bind("jdbc/AcmeDB", vds);

   // Creating a connection
   Context ctx = new InitialContext();
   DataSource ds = (DataSource)ctx.lookup("jdbc/AcmeDB");
   Connection con = ds.getConnection("genius", "abracadabra");