Prentice Hall and Sun Microsystems. Personal use only; do not redistribute.

18.2 Basic JDBC Example

467

18.2 Basic JDBC Example

Listing 18.3 presents a simple class called 

FruitTest

 that follows the seven

steps outlined in the previous section to show a simple table called 

fruits

. It

uses the command line arguments to determine the host, port, database

name, and driver type to use, as shown in Listings 18.1 and 18.2. Rather than

putting the driver name and the logic for generating an appropriately format 

ted database URL directly in this class, these two tasks are spun off to a sepa 

rate class called 

DriverUtilities

, shown in Listing 18.4. This separation

minimizes the places that changes have to be made when different drivers

are used. 

This example does not depend on the way in which the database table was

actually created, only on its resultant format. So, for example, an interactive

database tool could have been used. In fact, however, JDBC was also used to

create the tables, as shown in Listing 18.5. For now, just skim quickly over

this listing, as it makes use of utilities not discussed until the next section.

Also, a quick reminder to those who are not familiar with packages. Since

FruitTest

 is in the 

coreservlets

 package, it resides in a subdirectory

called 

coreservlets

. Before compiling the file, I set my 

CLASSPATH

 to

include the directory containing the 

coreservlets

 directory (the JAR file

containing the JDBC drivers should be in the 

CLASSPATH

 also, of course).

With this setup, I compile simply by doing  

javac FruitTest.java

  from

within the 

coreservlets

 subdirectory. But to run 

FruitTest

, I need to

refer to the full package name with  

java coreservlets.FruitTest ...

 . 

Listing 18.1  FruitTest result (connecting to Oracle on Solaris)

Prompt> java coreservlets.FruitTest dbhost1.apl.jhu.edu PTE 

        hall xxxx oracle

Database: Oracle

Version: Oracle7 Server Release 7.2.3.0.0   Production Release

PL/SQL Release 2.2.3.0.0   Production

Comparing Apples and Oranges

============================

QUARTER  APPLES  APPLESALES  ORANGES  ORANGESALES  TOPSELLER

    1     32248   $3547.28    18459    $3138.03      Maria

    2     35009   $3850.99    18722    $3182.74      Bob

    3     39393   $4333.23    18999    $3229.83      Joe

    4     42001   $4620.11    19333    $3286.61      Maria

Second edition of this book: www.coreservlets.com; Sequel: www.moreservlets.com.

Servlet and JSP training courses by book's author: courses.coreservlets.com.