Creating a Servlet which uses Templates

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We have thus far created a Servlet which can ask a database for information and display information from the database. Now we will use an HTML template to create a more attractive web page.

Preparing a Servlet to use Templates

Before our servlet can use templates, we need to add some more code to the declaration area of your servlet.

1. Choose "Goto declaration code" from the Code menu. This will take you back to the declaration code area of the HttpServlet Composer.
2. Click on the Code Sourcerer.
3. Choose 'File operations...' and press Next.
4. Choose the first option, 'Create a new File object from a pathname...' and press Next.
5. You will be prompted to enter the full pathname of the file. Press the browse button to the right to open a system-dependent file dialog. Select the Tutorial3 directory (found in the Project folder of your Simplicity Professional installation) and choose the file 'NameTemplate.html'.
6. Press done.

Next, we will edit the code in the doGet section of the code.

7. Go to the Servlet methods tab of the Servlet Composer.
8. Go to the doGet area.
9. Remove the last 2 lines of code from the doGet area. They will read

out.println(yourSales);

out.close();

10. Go to the top of the doGet area, and add 2 slashes (//) before the lines which begin out.println. This will prevent this code from being run.
11. Press the Code Sourcerer button.
12. Choose 'Template operations...'. Press Next.
13. Choose 'Create a new TemplateProcessor Object...' and press Next.
14. Press Next to keep the default name for the file object.
15. Press done to keep the default name for the TemplateProcessor.
16. Press the Code Sourcerer button again.
17. Choose 'Template operations...'. Press Next.
18. Choose 'Add name/Value pairs to a TemplateProcessor...' and press Next.
19. Press done to keep the default values for the name/value pair.
20. Edit the code that is generated so that "value" is replaced with s. The line should now read

templateProcessor.addValue("$name",s);

21. Repeat steps 16-20, except enter '$sales' for the name and 'yourSales' for the value.
22. Edit the code that is generated to remove the quotes from around yourSales.

After editing, this line of code should read

templateProcessor.addValue("$sales",yourSales);

23. Press the Code Sourcerer button again.
24. Choose 'Template operations...'. Press Next.
25. Choose 'Get processed text from TemplateProcessor'. Press done to keep the default name for the TemplateProcessor.
26. Press Ok to accept the default return value.
27. Type the following code into the doGet area. This code could be generated by the Code Sourcerer in Servlet Operations, if you wish.

out.println(processedString);

out.close();

Now you can test your code.

28. Choose 'Save' from the File menu to save your work.
29. Choose 'Initialize Class' from the Program menu. You have made changes to the declaration area of the Servlet, which need to be run.
30. Choose 'Execute init' from the Program menu. Initializing the Servlet will open the database connection.
31. Go back to the IDE without closing the Servlet Composer.
32. Open the html file you created earlier, NameForm.html, from the IDE. Your browser should open to the form page you created.
33. Try typing in a name and pressing "send".

Try different names, like "Carl" or "Fred". The TemplateProcessor uses an existing HTML file which contains replacement variables (named $name and $sales). This simplifies the creation of Servlets by keeping the HTML formatting in an .html file (created with your favorite HTML editor) and making programming the Servlet output much less confusing.