Download WebSphere 101 - itk.ilstu.edu

IBM Websphere Studio Application Developer (WSAD):
“Hello World” Hands-On
1. Start WSAD (Desktop > Java Tools > WebSphere Studio>WSAD 5.1.2 work - H
drive)
Assuming that you’re logged in with your course account and that you’d want to
save and retrieve your WebSphere projects from this location.
2. Create a new dynamic web project (File > New > Dynamic Web Project). Call it
MyProject1 and click Finish.
3. If prompted to repair the server configuration, click OK.
4. If prompted to switch perspective to “Web Perspective,” click Yes.
5. Expand the MyProject1 folder on the Project Navigator pane and you should see
the following:
6. With MyProject1 selected, create a new HTML page (New > HTML/XHTML)
called testing123.htm. Click Finish. This will add the web page to the project.
Note that the document is automatically added to the folder
/MyProject1/WebContent. All dynamic contents that are to be served up from
this web app are to be placed under this folder. (More on this later.)
7. Replace the default content “Place content here” with “Hello World Page Served
Up!” Note that this is in the Design mode. One can switch to the Source view by
clicking on the Source tab at the bottom of the pane.
8. Save the contents of the file (CTRL-S).
9. Now, serve up the page using the WSAD Test Environment. (Right click on the
testing123.htm and select Run on Server …)
10. You will be prompted with a window to choose the server that you wish to run
this document on. The first time you run this, you will be prompted to create a
new server. Select the WebSphere version 5.1, Test Environment. Click Next.
You will see that the default port number for the server is 9080. Click Finish.
11.
The server should start up (you will see many messages being echoed in the
Console pane in the process) and eventually you will see a browser pane showing
the HTML page. That’s it! Note the URL of the browser window, i.e.,
http://localhost:9080/MyProject1/testing123.htm. You can test this outside of
WSAD (e.g., in IE or Netscape) and it should work just fine.
12. Miscellaneous notes: From the echoed messages, note on the last line that the
server is “open for e-business.” Also, note that the server is listening to the default
port of 9080. Lastly, you can confirm the “Running” status of the server by
clicking on the Servers tab at the bottom pane.
13. Save the file Login.htm onto d:\temp. Now, import the file into Web Content
folder of MyProject1 (Select the WebContent folder of MyProject1, right click,
select Import, File System, Browse the d:\Temp folder, check the Login.htm
file, and click Finish.
14. Double click on the Login.htm file and note the statement
. (If you’re in the Design
mode, switch to the Source mode.) WSAD recognizes that the ACTION attribute
is referencing a program that does not exist. Thus, it gives a broken link warning.
15. Now create a servlet, call it LoginServlet (File > New > Servlet). Click Finish.
Note that by default the source file for the servlet goes to the folder
/MyProject1/JavaSource.
16. Replace the auto-generated contents with the following:
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class LoginServlet extends HttpServlet implements Servlet {
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
String userName =req.getParameter("userName");
String password =req.getParameter("password");
String outStr = "Hi " + userName + "<br>";
if (userName.length() < 5)
outStr += "Your login info is incorrect. Try again.";
else
outStr += "Welcome back. Please buy something this time :)";
ServletOutputStream out = resp.getOutputStream();
out.println(outStr);
}
public void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
}
}
17. Save the servlet (CTRL-S).
18. Now restart the project. Click on servers options at the bottom pane and rightclick on the server. Select ‘Restart Project’ and then click on ‘DefaultEAR’.
19. Now, serve up the Login.htm page (Right click on the Login.htm and select Run
on Server …). Choose the Use an existing server option with the WebSphere
v5.1 Test Environment. Click Finish.
20. Click Login Now button with the username “John”. (It doesn’t matter what you
type for password as the servlet doesn’t check it!) What do you get? Try username
“Billy” this time. You should get in this time.
21. Let’s try debugging with WSAD. Introduce a bug by changing the
LoginServlet.java class so that userName becomes username in the statement
String userName =req.getParameter("username");
22. Now go back to the Web Browser pane (within WSAD) and serve up the
Login.htm again. You should get the dreaded HTTP 500 (Internet server error)
message.
23. Look at the Console pane and you will see the details of the error (you may need
to scroll up so that you get to see the origin of the actual error). It is the ubiquitous
NullPointerException and it occurred at line 13.
….
[3/22/04 21:51:17:242 CST] 76b44936 WebGroup
E SRVE0026E: [Servlet
Error]-[LoginServlet]: java.lang.NullPointerException
at LoginServlet.doGet(LoginServlet.java:12)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
at
com.ibm.ws.webcontainer.servlet.StrictServletInstance.doService(StrictServletIns
tance.java:110)
…
24. Set a breakpoint at the beginning of the doGet method (double click on the right
edge stripe).
25. This time, start the server in the Debug mode by right clicking on the Login.htm,
select Debug on Server …
26. Choose the existing server when prompted and choose Restart when given the
message that the server is not running in debug mode.
27. You should see the debugger started with a new orientation of the windows. You
are in the Debug Perspective.
28. Click the Login Now button to start the process. When prompted to step into the
“Step-by-Step Debug,” click OK.
29. You are immediately brought to the breakpoint set earlier. Now Step Over the
statement and you will see that the variable userName is null. Step Over a couple
more times and you get to the null pointer location.
30. Now fix the bug (change the code (from username back to userName) directly in
the editor pane). Click on the Web Browser pane. Click on the Go back arrow.
Resubmit by clicking on Login Now. The servlet should again work properly.
31. Terminate the debug process (click on the square tool (Terminate) a few spaces
to the right of Step Over). You can switch back to the Web Perspective by click
on the Globe/WWW icon on the right most edge of the workspace.
32. That’s all folks!