Invoking screen-scraper from Java

Before we dig into the code let's review a few things related to invoking screen-scraper via Java. First, your Java code will need to have two jars in its classpath: screen-scraper.jar (found in the root screen-scraper install folder) and log4j.jar (found in screen-scraper's "lib" folder). For convenience we've packaged all of the files you'll need in this zip file. Download that file and unzip it. You'll notice that we also include an Ant build file that you can use to compile and run the sample class.

In order to invoke screen-scraper from Java, screen-scraper needs to be running in server mode. If you'd like a refresher on how to start up screen-scraper in server mode go ahead and follow that link, then come back here.

Okay, let's try it out before we dive into the code. Start screen-scraper running as a server. If you're using Ant simply type "ant run" at a command prompt inside of the folder where the build.xml files is found.

If that didn't go quite as you expected here are some things to check:

• Make sure screen-scraper is running as a server, and that nothing is blocking its ports (such as a firewall running on your machine).
• If you're running screen-scraper on a different machine than the one your Java class resides on, make sure that screen-scraper is allowing connections from the Java machine. In the screen-scraper workbench click on the wrench icon, then on the "Servers" button, and check the "Hosts to allow to connect" includes the IP address (or perhaps just the first part of the IP address) of the Java machine.
• Check screen-scraper's "log" folder for a "Shopping Site" log file. If you find one it means that screen-scraper is at least receiving the request. Open the log file in a text editor to see if you find any error messages.
• If you still can't seem to get it to work feel free to drop us a support request.

Assuming that test worked, fire up your favorite Java editor and open the "Shopping.java" file in it. The file is pretty heavily commented, so hopefully it makes sense what's going on. If not, try reviewing our Java documentation, posting to our forum, or sending us a support request.

When you invoke screen-scraper as a server it creates log files corresponding to your scraping session in its "log" folder. Take a look in that folder for your "Shopping Site" log file and take a look through it. It should look similar to what you see when you run scraping sessions in the workbench.