Derby - Storing ClientDataSource Objects on File System

JDBC Tutorials - Herong's Tutorial Examples

∟Derby (Java DB) JDBC DataSource Objects

∟Derby - Storing ClientDataSource Objects on File System

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

JNDI File System Service Provider offers a directory service which allows you to store Java objects on the local file system. You can use this feature to create a Derby JDBC ClientDataSource object and store it on the local file system. That stored ClientDataSource object can be retrieved later whenever you want to use it.

To store a ClientDataSource object on the local file system, I need to:

Initiate the directory service with RefFSContextFactory class.
Assign a file system directory as the service home directory.
Create a ClientDataSource object with correct access information for the Derby Network Server.
Bind the ClientDataSource object to a name to store it to the file system.

I wrote the following sample program to store my ClientDataSource object to the file system via JNDI:

/* DerbyJndiBind.java
 * Copyright (c) HerongYang.com. All Rights Reserved.
 */
import java.util.*;
import java.sql.*;
import javax.sql.*;
import javax.naming.*;
import org.apache.derby.jdbc.*;
public class DerbyJndiBind {
  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);

// Creating a DataSource object
      ClientDataSource ds
        = new org.apache.derby.jdbc.ClientDataSource();
      ds.setServerName("localhost");
      ds.setDatabaseName("TestDB");

// Storing the DataSource object
      ctx.bind("DerbyTestDB", ds);
      System.out.println("ClientDataSource object stored ok.");

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

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

herong> javac -cp .;derbyclient.jar DerbyJndiBind.java
Note: DerbyJndiBind.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.

herong> java -cp .;derbyclient.jar;fscontext.jar;providerutil.jar \
   DerbyJndiBind
ClientDataSource object stored ok.

herong> java -cp .;derbyclient.jar;fscontext.jar;providerutil.jar \
   DerbyJndiBind
Exception: DerbyTestDB

Note that:

The compilation gave me a warning message. Don't worry about it for now.
When I ran the program for the second time, it gave me an exception because the name "DerbyTestDB" has already been used to store the ClientDataSource from the first execution.