Exploring JDBC and XML - JDBC Drivers
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Creating a Java program that uses a JDBC driver is similar to creating one that uses the JDBC-ODBC bridge.
The first step is to acquire and install a JDBC driver. Sun does not include a JDBC driver with Java 2, but more than a dozen companies, including Informix, Oracle, Symantec, IBM, and Sybase, sell drivers or package them with commercial products. A list of available JDBC drivers can be found on Sun's JDBC site at http://java.sun.com/ products/jdbc/jdbc.drivers.html.
The developers of the MySQL database offer Connector/J, a free open source JDBC driver developed by Mark Matthews. Some of these drivers are available to download for evaluation.
To download this driver or find out more about it, visit the Web page http://www.mysql.com/downloads/api-jdbc.html.
NetDirect offers a JDBC driver as part of the JDataConnect Server, which is available for trial download from http://www.j-netdirect.com.
After you have downloaded and installed a JDBC driver, the steps for setting up a data source for JDBC are the same as with the JDBC-ODBC bridge:
Create the database.
Associate the database with a JDBC driver.
Establish a data source, which may include selecting a database format, database server, username, and password.
Listing 20.3 is a Java application that uses the JDataConnect JDBC driver to access a database file called People.mdb. This database is a Microsoft Access file with contact information for U.S. presidents.
Listing 20.3 The Full Text of Presidents.java
1: import java.sql.*;
2:
3: public class Presidents {
4: public static void main(String[] arguments) {
5: String data = "jdbc:JDataConnect:
//127.0.0.1/Presidents";
6: try {
7: Class.forName("JData2_0.sql.$Driver");
8: Connection conn =
DriverManager.getConnection(
9: data, "", "");
10: Statement st = conn.createStatement();
11: ResultSet rec = st.executeQuery(
12: "SELECT * FROM Contacts ORDER BY NAME");
13: while(rec.next()) {
14: System.out.println(rec.getString("NAME")
+ "\n"
15: + rec.getString("ADDRESS1") + "\n"
16: + rec.getString("ADDRESS2") + "\n"
17: + rec.getString("PHONE") + "\n"
18: + rec.getString("E-MAIL") + "\n");
19: }
20: st.close();
21: } catch (Exception e) {
22: System.out.println("Error -- " +
e.toString());
23: }
24: }
25: }
Using this application with another database and driver would require changes to lines 5 and 7.
The JDataConnect Server can be used to connect remotely to servers on the Internet, so 127.0.0.1 could be replaced with an Internet address, such as db.naviseek.com:1150, if a JDataConnect Server is running at that location and port.
Line 5 creates the database address that will be used when creating a Connection object representing the connection to the Presidents data source. This address includes more information than the one used with the JDBC-ODBC bridge driver, as shown:
jdbc:JDataConnect://127.0.0.1/Presidents
Line 7 of the Presidents application loads the JDBC driver included with the JDataConnect Server:
JData2_0.sql.$Driver
Caution - NetDirect's JDataConnect Server uses the ODBC Data Source Administrator to create a new data source associated with a database.
On Windows NT, 2000, and XP, you must set up the data source using the System DSN tab rather than the User DSN tab. This is required because the JDataConnect Server connects to the database outside your account, so it must be available to all users on your computer.
Before this program will run successfully, the JDataConnect Server must be started, unless it is already running (on a Windows NT or Windows XP system, it is set up as a service during JDataConnect installation and does not need to be started manually). The reference to 127.0.0.1 in line 6 refers to this server; 127.0.0.1 is a substitute for the name of your own machine.
Configuration information for the data source and driver is provided by the company that developed the JDBC driver. The database address can vary widely from one JDBC driver implementation to another, although there should always be a reference to a server, a database format, and the name of the data source.
If the People.mdb database exists, the database has been associated with an ODBC data source, and the JDBC driver has been set up correctly, the output of the Presidents application should be similar to the following (depending on the records in the database):
Gerald Ford
Box 927
Rancho Mirage, CA 92270
(734) 741-2218
library@fordlib.nara.gov
Jimmy Carter
Carter Presidential Center
1 Copenhill, Atlanta, GA 30307
(404) 727-7611
carterweb@emory.edu
Ronald Reagan
11000 Wilshire Blvd.
Los Angeles, CA 90024
library@reagan.nara.gov
George Bush
Box 79798
Houston, TX 77279
(409) 260-9552
library@bush.nara.gov
Bill Clinton
15 Old House Lane
Chappaqua, NY 10514
(501) 370-8000
info@clintonpresidentialcenter.com
George W. Bush
White House, 1600 Pennsylvania Ave.
Washington, DC 20500
(202) 456-1414
president@whitehouse.gov
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 This article is excerpted from chapter 20 of the book Sams Teach Yourself Java 2 in 21 Days, 4th Edition, written by Rogers Cadenhead and Laura Lemay (Sams; ISBN: 0672326280). Check it out today at your favorite bookstore. Buy this book now.
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