I'm pretty new to web development, so I had some basic questions to get me pointed in the right direction.
For the last week I've been learning the rails framework, and from what I understand, this framework is great for building a website, but you still need javascript to build nice front-end interface/apps that run in the browser. Is this understanding correct? If not, why does javascript appear to be so essential to almost al websites? In other words, what can you do with js?
Also, I was wondering if it is necessary for me to learn javascript now that there are tools like GWT that compile Java into js. I ask because, I am proficient in Java but have no knowledge when it comes to javascript. How far can GWT take me before I need to learn javascript, or do I have to learn javascript at all?
If someone could point me int he right direction by answering these questions, I'd be very grateful.
Thanks
GWT compiles Java to JavaScript, but you still will need to learn about web development.
I have seen many projects going wrong with GWT because people just started writing Java code and did not care about the underlying platform (the browser) at all.
If you don`t want to care about the browser use some plugin technology (if you are an app inside a controlled environment), otherwise first learn about how to build apps with HTML + JS + CSS.
Eventually you will discover that GWT is a great toolkit for writing fast JavaScript apps in Java, that packs many best practices for building web apps inside the toolkit. It has good abstractions, but every abstractions leaks so you will need to have good knowledge of the browser. You will save on things like keeping away from the bad parts of JavaScript.
I'm working with GWT now, and I haven't had to use Javascript at all yet. I'd say for most websites, GWT should be fine.
I know this question might be repeated many times but would really appreciate any suggestions. I am working on developing a web application in java (server side). The client is developed in javascript and html5 (another guy) and i want to make the developement independent. I have been using java for quite long but have no experience in web development. After endlessly going thorugh many forums and articles i am so confused.
The web app is pretty simple one with options for user to login and upload some data and access those later.
I started with basic sevlets and JDBC APIs. The web application is not very complex one
Currently i have servlets for each resource to handle post and get call on them.
The suggestion i am looking for is do i need to use some framework to make it better. There are so many like springs, playframework, wicket etc.
Any link to sample web applications developed just usin servlets apis will also do a great deal to me
Thanks in advance for the suggestions
I don't think you need any framework. As you said your app was pretty simple one. A java Framework could make a complex app organized. But would make a simple app complex.
However, if in the future, you want to extend your app further more. you might need a framework. The most famous web frameworks in java are SSH(spring, struts, hibernate), you can find a lot of materials easily, so I won't dive into the detail here. SSH frameworks are not easy, avoid using them if you app is not complex enough.
I have a really simple J2SE app that consists of a couple of classes. I plan to make it available to my co-workers, and I've been thinking the easiest way would be for them to access it from a browser, instead of distributing the executable on each machine.
What's the easiest method/framework that would allow me to do this? This app is pretty targeted-- it will just perform the same isolated operation, and will have some activity against the DB --but the logic is already implemented on the app. The interface would only require some input from users (login,password,ip,etc), an action component to trigger the process and nothing else.
I've been thinking of a simple JSP/Servlet app for it, but wanted to see what's available now. If any how-to link is available, would be great.
Axis allows you to to create web services from existing java classes. But this may require writing a desktop client.
Grails framework can use existing java classes and is easy to use. It follows MVC pattern similar to Ruby on Rails.
If you don't need anything complex, and you're ready to to write html with System.out.println() thenjust write a simple servlet. There are many guides online, it's very straightforward.
If the application is simple, then use simple JSP/Servlet, otherwise MVC framework(Struts...) could be used here. But using MVC framework leads learning curve.
It's kind of trade-off: you could decide the learning curve is worthy or not in your application.
Sorry for asking this question, but I searched all Java-related questions, but I got more confused. I am still not clear what should I start with.
My main thing is building websites in Java, because someone told me that there are some machine learning or AI libraries available in Java which I can use in Java. So I decided to use that as it can reduce my work.
Now I don't know Java at all. Some people say the following are used to build websites, like:
Servlets alone can build a website
JSP alone can also build a website
Struts
Spring Framework with Hibernate
Seam
Java EE also for websites
I am confused. Where should I start from? Where does core Java fits in here?
I was thinking of perhaps learning Python as I know I have to learn Python only, not its variations.
So please guide me to one thing which can solve my basic purpose of using ready-made libraries of AI.
If I can do that with JSP then I will start with that.
But if I need to learn all of them, then it’s better if can start learning Python.
I have five months to finish the website.
I really don't know why there are many branches of Java for doing one thing.
To correct some misconceptions of yours:
servlets and JSP are Java EE
Seam and Struts can be used together with Hibernate as well
Spring MVC is a web framework. Spring as a dependency injection framework can be used together with any other framework.
there are many more options, like JSF, Tapestry, Click, Play, etc.
It depends on what will the site will be doing, but you can choose any.
Experience has shown that building complex HTML forms (especially validation) and Ajax functionality is hard to get right. You will most likely appreciate having a library to assist you with that. The same thing with database access.
Everything builds on servlets. Learn those in order to understand the libraries you will use.
I would suggest learning JavaServer Faces (JSF) with facelets. The easiest, while being powerful, is JSF 2 in Java EE 6. The easiest way to get started is to use NetBeans with GlassFish 3.
For static web pages, HTML alone is enough and if you want to make it more user-friendly and interactive, use JavaScript.
There are lot of frameworks you can use directly in JavaScript, like jQuery. Now if you want to make some more functionalities, like database interaction, then you will need either PHP, Java (JSP and Servlets) or .NET (there exist some more, but I’m aware of three only). Each of them have their library to interact with database.
Since you are interested in Java, go through Servlets, HTML, JavaScript, and JSP. Once this is done, you can look into JSF and EJB beans. So if you have knowledge of Java this will not take too much time, because the syntax is the same; the only difference is the concept.
So you will have a frontend (HTML, JS, and JSP) which will interact with the backend (Servlets and the database) which will be deployed in a Web container. To deploy, you can use an one of the available application servers, like Apache Tomcat, GlassFish, or WebSphere. To develop your application, you can use Eclipse as the IDE, which is one of the best IDEs I have used.
So decide your architecture and design, break it into components and start writing small applications first. Once you are experienced in small application, start writing an application where there are more things you have to care of, like load on database, availability, security, etc. For that, you can refer a very famous question on Stack Overflow, What technical details should a programmer of a web application consider before making the site public?.
The closest to core Java is servlets. No extra syntax, very minimal library, but no included functionality.
For building websites, the main thing is HTML and HTTP.
All technologies (including Enterprise Java or Server side Java) do the same—to understand an HTTP request and respond back with HTML. All that you mentioned do the same thing with a different level of sophistication.
Start with Wikipedia.org to know what technologies do what. If you are completely new to Java, go through the Sun tutorials, do sample programs, and get comfortable with Java packages, JVM and classes. (This might take a week or two).
To build websites using Java, you'll have to learn Java Servlets—everything else (JSP, Struts, JSF, and Spring(!)) are built on it. Get Head First books on Java and Servlets; they will be useful.
You can always build the page in Ruby or something that will give you a website very fast. For the AI stuff that analyzes the bought items for the recommendations, use something unrelated to the page that only takes the database to work with.
I would not mix the whole web page stuff with the AI computing. You can do the AI things that will take a long time and maybe should done on a different machine to have your webpage also responsive with C++ or Java in normal applications.
Choosing your front end technique because of later usage is a very dangerous thing. Using the whole Java EE concept and learning it from scratch will take you much longer than have a quick start with your page if you do it in Ruby or PHP.
You can then build the first version of the page and generate a user base. Start working on the AI stuff once you got some data with other technologies.
If your page has performance problems because your technology does not scale, you can always begin switching parts of the stuff out with a faster technology or maybe simply a bigger machine. Get your page running before you build it bulletproof for the thousand users you are expecting.
If you’re trying to build a website from scratch, with no prior knowledge, your best bet is to go with frameworks that provide a complete stack for web development.
If you aren't dead set on Java, you could probably start learning Ruby on Rails, which would be easier to start with (if so, go buy a Ruby on Rails tutorial which goes through all the necessary things for modern web development, from MVC to version control).
For Java, try:
Play Framework is very similar to Ruby on Rails. It will get you started very quickly, and hopefully (if you follow conventions) handle all of your peripheral needs.
Spring Roo is a very-fast-to-work-with framework, but it might get hard to maintain and extend later on.
These two are full web frameworks, that is, they handle database, MVC (presentation layer), configuration setting, etc... (I'll explain shortly). And could even ease your deployment process.
If you're going to go through any other route (using several frameworks together), you are probably not going to finish what you are doing in five months.
To understand why, and to clear some things you wrote in your question, you need to understand that modern web development (and enterprise development as a whole) is comprised of several different technologies:
Presentation: the term web frameworks has been more or less taken to mean frameworks that deal with this side of web development, i.e., how to create a web page (an HTML page). Most of the frameworks offer an MVC like approach (which you can read about elsewhere), and this is what most of the frameworks/technologies you gave sit in—JSP and Struts (which uses JSP) are examples of web frameworks. Servlets is a lower-level API that standardizes how to answer HTTP requests (which JSP and Struts sit on top of).
Persistence: being able to show a webpage doesn't mean squat these days if you can't save data to a database, and that is what the persistence frameworks do (they ease the way you can save data to the database). Hibernate is a persistence framework.
For Java there are also dependency injection (DI), which is what Spring DI is. It's tough to explain DI to people not familiar with the troubles of Java, so I won't try to explain it, but it's a very important part of modern Java development.
apart from these core technologies, there are also many items that you'll need to learn to actually deploy the application (unless your using services like Heroku or Google App Engine, which should simplify things), and troubleshoot it later (understanding how concurrency and HTTP works).
To address the other technologies you brought up:
I've never really touched Seam, so I'm not sure, but it looks like a collection of other frameworks (mainly EJB 3, which itself is a collection of APIs, and JSF).
Spring denotes a popular open source group (the SpringSource group) that provides various technologies, but most likely when you hear about it they refer to two things Spring's dependency injection (DI) and Spring's MVC (which is a web framework).
Java EE is merely a collection of high level APIs which other technologies implement (Hibernate implements JPA which is part of Java EE for instance).
I've Inheritted a large Java Web project which I've got to make some modifications to, I'm a fairly competent Java Programmer when it comes the the basics but I've never done any JSP programming or EJB programming before. I remember vauguely doing some servlet programming 5 or so years ago in university, but I'm assuming that everything has changed since then.
I'd planned on getting myself up to speed this weekend, but I don't know where to start.
What would be a good learning trail to get me from Zero to proverbial Hero? or at least to a level of competency which will let me be able to read the JSP servlet and EJB code and understand how it works well enough to modify it and deploy it?
Ofcaurse it depends a lot on what project you inherited and when it was written.
Also what technologies are used?
The best resource on starting J2EE development I think it's the Java Passion site.
The online tutorial on netbeans.org are very good. I recommend to download the NetBeans 6.5 IDE (free) and walk through the J2EE tutorials.
The tutorials are very well written, and introduce the basic elements of enterprise and web development. They also require very little time to complete.
http://www.netbeans.org/kb/
Find out how complex it is. There is a vast difference between a web application without EJB's and one with.
Is it running in JBoss/Tomcat/Jetty/Resin/BEA/WebSphere?