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) 2007 by Dr. Herong Yang. 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:
C:\>javac -cp .;\local\javadb\lib\derbyclient.jar DerbyJndiLookup.java
Note: DerbyJndiLookup.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
C:\>java -cp .;\local\javadb\lib\derbyclient.jar;
\local\lib\fscontext.jar;\local\lib\providerutil.jar DerbyJndiLookup
List of Addresses:
1, 5 Baker Road, Bellevue
2, 25 Bay St., Hull
3, 251 Main St., W. York
