Now for this application, as I wrote it in a matter of days and released it the day of schedule releases, I had to go with a language I knew very well, and I had to have a reliable, dependable source to host it at. I automatically though of the Google App Engine as it is pretty sweet to play around with and now would be a great time to test it in a live environment. My previous application I had wrote on Google’s free, scalable engine was written in Python. It utilized the amazing Django framework, but I felt like I didn’t really understand the Python language as well as some others. The only other option for selection on the App Engine was Java. This was perfect as I had just completed a summer class on Java and it was extremely fresh in my mind.

Core Java Servlets

Now coming from PHP for web development the idea of Servlets and JSP’s was totally a different way of thinking. With PHP I was used to putting what code I needed to on each page to achieve what needed to be done. With a bit of Python/Django experience, Java’s way was still different, but not as different as PHP to Java. Java’s JSP method reminded me a lot of Django templates, except that JSP’s are a load more powerful. As Django templates (at least from my experience) only allow a few tags, a JSP allows practically any Java code (that would normally go inside a main method) and allows imports and special features unique to JSP’s, like includes. JSP’s includes in fact reminded me some more of Django’s templates with all the splitting up possible of the HTML files.

Now that we briefly know what a JSP is, a servlet is just like a Java class that implements the standard Apache servlet. Within these servlets you have two methods by default doGet(HttpServletRequest req, HttpServletResponse resp) and doPost() with the same arguments. There are a few differences from a standard Java class beyond those previously noted:

resp.getWriter().println(); // to print to the screen you must get the PrintWriter via the resp.getWriter() method
resp.setContentType("text/html"); // must do if you print out any HTML and don't want it to appear as standard text
resp.sendRedirect(String url); // a simple way to send a user to be redirected

There is (obviously) no console input on a web browser, so the standard way to get input via the web is through GET and POST methods. These are handled via the corresponding doGet() and doPost() methods. Now to actually get the value passed, you must know the variable name and use it accordingly.

req.getParameter(String paramName); // where paramName is the ?name=Joe&age=18 name or age

Sometimes you will also find yourself in need of getting an array, from say a multiple choice drop down.

req.getParameterValues(String paramName); // just once and it will return a String[]

Now onto more of the theory behind servlets, and less of the syntax. Now please remember when I say theory, this is just the way I perceive it. In my application if I would have a full blown HTML page, I would always put it in a JSP as it is so simple and better looking. However when there was a simpler page that had a bit more code behind it, I would make that a servlet. An example of a simpler page with more code that I used as a servlet would be my form handlers (any adding or updating interaction with the database), and also I handled the OAuth authentication with servlets.

JSP’s

JSP’s, or Java Server Pages, are a mix between Java code & client-side scripting. It allows you to mix the power of Java and your the models in your MVC framework with the simplicity of a HTML file. You probably see them all over the web, as they are quite effective, especially in larger businesses and universities.
I have not personally gone that far into all the powers of JSP’s but enough to know that I like them. I am not going to try and write a tutorial but just point out a few things I use and a good tutorial or two.
Now one of the simplest, but greatest is the server-side include of static content. This allows you to keep your web pages on the server side leaner and able to easily change base things like headers or footers.

<%@ include file="/include.html" %>

Other useful things to know, if you need to get any parameters or need to mess with the request or response, they are simply called request and response in all JSP’s. So you could use a request.getParameter("id"); for example.
If you need to write anything to the page from within the Java code just throw a out.println(String value); or out.print(String value).

For anything more than what I included check Google for some JSP tutorials or here is a good looking one.

Benefits

I see there being several benefits of using Java as the language behind more complex applications because of it is an object oriented language. It being OO allows code to get so many more times complex. Now, in web development at least, a OO language is only as good as the database that supports it . I happened to be very lucky with Google App Engine as it was powered by a OO database allowing me to store some of my unique data types like “Student”, “Teacher”, “Course”, and “Schedule” in the database and retrieve it like it has been open since it was created. Most of the interface for this was provided in the JDO classes in javax.JDO.
With this and a few classes for getting and selecting certain Students/Teachers/Courses, it was very easy to get exactly the results I want in a few lines of code in a JSP. And I know that in Python and PHP you can have classes and objects, but it’s just not the same as it is in Java. While Java can be pretty strict with it’s types and defining them, it in turn gives a lot of power to create awesome and dynamic applications for the end user.

Finally

As I have been reading in my “Clean Code” book, it is better to take longer and write software better the first time. Better being Javadoc’d and Object-Oriented. If you were to write it the other way, with say PHP or Python and have each script access the relational database, get the results, sort the results into the data you need, and output it correctly, that is so much code duplication. One script could be anywhere from 20% – 50% of the same code over and over, why not just write it great in the beginning in an OO way so the only code duplication you have is one or two lines to load the pre-written-by-you libraries that does all that work in one place, one time.

And sorry Brent I think I like Java Servlets & JSP’s a wee bit more than Python/Django even though I think Django is a great framework and would love if it were written in Java instead, Python just isn’t as big and powerful as Java.

Update: 4 left!

Update: 3 left!

I have tried PHP frameworks before such as CodeIgnitor, they were nice, but nothing special. Trust me, Django is special! It has so much available the second the installer says finish. If you have been procrastinating because you don’t know how to set it up on your server or something stop, don’t; host it on Googles servers! Google App Engine allows you to build Python and Java web applications on their fast, large infrastructure. It comes with a SDK for building apps and also with a localhost for building your applications. I have not tried out the Java part yet, but I have been enjoying creating a Twitter-like micro-blogging service on it. It is simple and you have access to all the tools that make Google so great like Gql and the WebAPP framework. It is really worth the time and someday maybe you will move your site over to Django and Python as I soon hope to do.

Case in point: If you haven’t tried Django, get out and do it, if you have don’t you love it?

Yes I do agree that Yahoo comitted suicide. It’s Yahoo is a swimmer in the ocean and grabs a weed for help, but little does it no that the weed will pull it to the ocean floor and it’s demise. Bing at 8% of the search engine world was no competition with Google, it never has been, I personally think Bing and all of MSN ( sorry, Windows Live ) has always been a joke. Nobody uses it, when was the last time you heard someone say “Bing it!” instead of “Google it!”. If my 70 year old minister says “Googled” in reference to the search engine giant, I believe that shows just how powerful it is.

To add to Bings tiny 8% it adds the respectable Yahoo, which is approximatley 20% of the search world. I respect Yahoo, they have a few nice products such as Pipes, Flickr, and Mail though I only use the first two. It’s search is respectable and is my second favorite.  So Yahoo takes its 20% share, more than twice Bings and gives it all to Bing. Yahoo shall become Bing. Since when has the weak ruled the strong? This “agreement” I believe is one sided, yes Bing shall grow a little bit but it will never come out at 28%. If Yahoo had added Bing, the tables would have been completley different.

Google, I think this just makes your job easier, two birds, one stone. And as an added bonus  the birds are weaker now.

Google vs. Apple

While not a competition I do see a little battle here after Apple has rejected Google products like Latitude and Voice. Saying there features are too much like the standard iPhone features. Most people believe this is due to the pressure from behind, nasty AT&T. Anyways this is not a fair deal to reject premium grade software after they have spent a long time working on it, I have browsed the iTunes App Store and to say the least it is amazing how much crap they let on there and too not let well built, rich apps like Latitude and Voice is stupid. Google you should be ticked off.

Google vs. Microsoft

More of a sidenote but I find Microsoft Azure very amazing and remarkably related to Google App Engine. Azure, featuring Azure SQL, ASP and .NET programming is worthless for their intended audience. Anyone who uses Microsoft programming languages like ASP and .NET has no use for cheap/free cloud services as they obviously have plenty of corporate money. Google App Engine though, it more opensource, more developer accepted and not centered around Google, but around the target audience.

I’m expecting Microsoft Typhoon any day now.

Google you have my support in every way. Good luck, I know you shall come through.

My Google Wave Inbox

My inbox is full off all the developer group conversations and I tweeted with this twitter api . I am looking forward to possibly making an app. I  saw they have no wave to RSS thing, so that would be a nice thing to have, to follow a big colabrative wave or that could be an odd sort of joint blog?? Anyways cool! More coming tommorow

As they say in the Lion King, “Be Prepared!” ( you know, the song! Scar sings. ). Anyways, I just watched the whole 1 and 1/2 hour demo. Dang it’s looking good. Basically they take the whole web mash it into their website and open source it. It is email to the 10th dimension. It can be sent between two servers, A and B. It has all the same functionality between A and A as A and B. It is Internet 2.0. It will quickly kill many things, it is very similar to Facebook except bigger, and more flexible.

The thing I am most surprised about is the Open Source! They want to model it after E-mail, it was open sourced and it became the standard for 40 years, until Waves came. If you thought G-Mail was superb ( as I did ) then this will boggle your mind. Watch at least part of it, it is flexible, exstendable and futuristic. It is everything it is SVN, Office, Solitare, Youtube, Flickr, Facebook, Hotmail all in one open sourced and on a clean website. I just hope that people don’t see Wave as a geeky weird thing and deem it as too hard, I hope the read into it and switch. Think of the possibilities in a work place, in any place.

If there is one futuristic company out there, it’s Google. Microsoft is old and corrupt, Apple too small and too weak, Yahoo is not inventive. Google is futuristic, youthful, powerful, large, and intuitive. Boys and girls, I don’t want to work at a old, small, or not inventive company, I want to work at Google and be the future.

I signed up at wave.google.com to help, I asked them to let me on to build some project for them, I am thinking eithier a interaction between like FlickR or something where the photos you shared could also be added to FlickR or something, and I would also like to Wave my site and be riding the wave of the future.

Another point I found really interesting was that they programmed it all in Java and had had Google Web Toolkit convert it. Interesting. HTML 5 is also interesting that they would use something that far into the future. Well I guess if Wave is going into the future so should what its built on. Cool.