Derby - Looking Up ClientDataSource Objects on File System

JDBC Tutorials - Herong's Tutorial Examples

∟Derby (Java DB) JDBC DataSource Objects

∟Derby - Looking Up ClientDataSource Objects on File System

This section describes how to lookup a Derby JDBC ClientDataSource object in the file system using JNDI File System Service Provider.

Once the my CliendDataSource is stored on the file system through the JNDI directory service, I can get it back any time I need to create a connection to the Derby Network Server. What I need to do is:

Initiate the directory service with RefFSContextFactory class.
Assign the same file system directory as the service home directory.
Lookup the ClientDataSource object by its name.

I wrote the following sample program to retrieve my ClientDataSource object from the file system using the directory service via JNDI:

/* DerbyJndiLookup.java
 * Copyright (c) HerongYang.com. All Rights Reserved.
 */
import java.util.*;
import java.sql.*;
import javax.sql.*;
import javax.naming.*;
public class DerbyJndiLookup {
  public static void main(String [] args) {
    Connection con = null;
    try {

// Starting the Directory service
      Hashtable env = new Hashtable();
      env.put(Context.INITIAL_CONTEXT_FACTORY,
        "com.sun.jndi.fscontext.RefFSContextFactory");
      env.put(Context.PROVIDER_URL, "file:/local/fscontext");
      Context ctx = new InitialContext(env);

// Looking up the DataSource object
      DataSource ds = (DataSource) ctx.lookup("DerbyTestDB");

// Getting a connection object
      con = ds.getConnection();

// Running a query
      Statement sta = con.createStatement();
      ResultSet res = sta.executeQuery(
        "SELECT * FROM HY_Address");
      System.out.println("List of Addresses: ");
      while (res.next()) {
         System.out.println(
           "  "+res.getInt("ID")
           + ", "+res.getString("StreetName")
           + ", "+res.getString("City"));
      }
      res.close();
      sta.close();

      con.close();

    } catch (Exception e) {
      System.err.println("Exception: "+e.getMessage());
    }
  }
}

Here is the output of compilation and execution of the program:

herong> java -cp .;derbyclient.jar;fscontext.jar;providerutil.jar \
   DerbyJndiLookup

List of Addresses:
  1, 5 Baker Road, Bellevue
  2, 25 Bay St., Hull
  3, 251 Main St., W. York