General

“Hello, World” Web Application using Spring MVC in NetBeans IDE 6.7

1328 days

by tabrez in General

If you are looking to learn web application development with Spring Web MVC framework NetBeans is probably the best IDE to get started with. You don’t have to worry about which framework library files to download, where to copy them etc. and moreover some of the basic configuration is automatically created as part of project template creation wizard. Below is an example “Hello, World” web application created using Spring Web MVC framework in NetBeans IDE.

Start NetBeans IDE and create a new project File -> New Project…
Select “Java Web” in Categories section and “Web Application” in Projects section and click Next.

Enter a name for the project in “Project Name:” field(say “HelloWorld”) and click Next.
Change any of the server settings(like selecting a different web server instead of the default Glassfish) if you want to, otherwise just click Next. Finally, make sure that you check the “Spring Web MVC 2.5″ checkbox and any additional frameworks you plan to use for this web application(like Hibernate) and press Finish.
NetBeans does a nice job of creating a template Spring Web MVC project for you by copying the required spring jar files in web application build directory, generating configuration files with sample content etc. You can see that web.xml has the required configuration lines already. Also have a look at dispatcher-servlet.xml file to see handler mapping bean and view resolver bean already declared. (Netbeans should have it opened automatically; if not, open it from HelloWorld -> Web Pages -> WEB-INF.) Run the application to see what the sample project currently does.

Now let us add our own code to the application.

First step is to create the controller class. Right-click on Source Packages and select New -> Java Class. Enter HelloController in the “Class Name:” field and hello in “Package:” field. Click Finish.

Enter the following code in the HelloController.java file.
[java]
package hello;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.AbstractController;

public class HelloController extends AbstractController {

@Override
protected ModelAndView handleRequestInternal(HttpServletRequest arg0, HttpServletResponse arg1) throws Exception {
String message = “Hello, World!”;
return new ModelAndView(“response”, “msg”, message);
}
}
[/java]
Open dispatcher-servlet.xml and add a mapping from hello.htm URI to HelloController controller class as shown below.
Time to create the response page. Right-click on jsp directory(Web Pages->WEB-INF->jsp) and create a new JSP file. Since we are returning “response” as the view name from our controller class, enter “response” in the “JSP File Name:” field. Click Finish.
Now open the response.jsp page we just created and enter the following code in it.
Run the application and change the request uri in the browser address bar to http://localhost:8080/HelloWorld/hello.htm and press Enter. You should see the following response page.

NetBeans IDE saves a bit of time by generating a configured Spring Web MVC project for us to start with. With most other popular IDEs, we need to install the required library files and create the basic configuration files manually. I will describe the procedure using Eclipse IDE in my next post.

Installing Sun Java SE 6, Apache Maven 2 and Tomcat 5.5 on Ubuntu GNU/Linux

1534 days

by tabrez in General

Installing Sun Java SE 6, Apache Maven 2 and Tomcat 5 on Ubuntu GNU/Linux

First go to System -> Administration -> Software Sources and make sure that the multiverse and universe Ubuntu repositories are enabled on your system.

Installing Java SE 6, Apache Maven 2 and Apache Tomcat 5.5 software is just one simple command on Ubuntu family of GNU/Linux operating systems:

# sudo aptitude install sun-java6-jdk tomcat5.5 jetty maven2

I recommend setting JAVA_HOME environment variable to point to the JDK installation directory in your profile file(e.g. .bash_profile or /etc/profile):

export JAVA_HOME /usr/lib/jvm/java-6-sun

The above command also installs the jetty web server which is especially good for development purposes.

“Hello, World” Java Web Application using Java SE 6 + Tomcat 5.5 + Maven 2

1584 days

by tabrez in General

See my previous posts to install Sun Java SE 6, Apache Tomcat 5.5/6, Apache Maven 2 on Windows and Ubuntu GNU/Linux operating systems:

Once all the required software components are installed, simply run the following command in the command prompt/shell to generate a basic Java web application project in the current working directory.

# mvn archetype:create

You can also run ‘mvn archetype:generate’ if you want to generate the project in interactive mode. The command will then prompt you for relevant information when creating the project.

# mvn archetype:generate
[INFO] Scanning for projects…
[INFO] Searching repository for plugin with prefix: ‘archetype’.
[INFO] org.apache.maven.plugins: checking for updates from central
[more output]

After all the necessary files are downloaded, you will be shown a list of supported archetypes and will be prompted to select the one that you want to generate.

[INFO] Generating project in Interactive mode
[INFO] No archetype defined. Using maven-archetype-quickstart (org.apache.maven.archetypes:maven-archetype-quickstart:1.0)
Choose archetype:
1: internal -> appfuse-basic-jsf (AppFuse archetype for creating a web application with Hibernate, Spring and JSF)
2: internal -> appfuse-basic-spring (AppFuse archetype for creating a web application with Hibernate, Spring and Spring MVC)
3: internal -> appfuse-basic-struts (AppFuse archetype for creating a web application with Hibernate, Spring and Struts 2)
[more options]
42: internal -> cocoon-22-archetype-block-plain ([http://cocoon.apache.org/2.2/maven-plugins/])
43: internal -> cocoon-22-archetype-block ([http://cocoon.apache.org/2.2/maven-plugins/])
44: internal -> cocoon-22-archetype-webapp ([http://cocoon.apache.org/2.2/maven-plugins/])
Choose a number: (1/2/3/4/5/6/7/8/9/10/11/12/13/14/15/16/17/18/19/20/21/22/23/24/25/26/27/28/29/30/31/32/33/34/35/36/37/38/39/40/41/42/43/44) 15: :

Enter the appropriate number to select the archetype that you want to generate; for example, enter 18 to create a basic Java Web Application project. Next you will be prompted to enter values for groupId(say ‘hello’), artifactId(say ‘HelloWorld’), version(you can accept the default and just press the ENTER key) and package(say ‘war’). You will then be asked for confirmation; type Y and press the ENTER key. For more information on what the above fields mean, read about Maven Co-ordinates.

To learn more about Maven’s archetype plugin, read Maven 2 Archetype plugin usage page.

You can run the basic Java web application project created above in Tomcat web server by running the following command.

# mvn tomcat:run
[lot of output]
[INFO] Starting tomcat server
[INFO] Starting Servlet Engine: Apache Tomcat/5.5.15
[INFO] XML validation disabled
[INFO] Initializing Coyote HTTP/1.1 on http-8080
[INFO] Starting Coyote HTTP/1.1 on http-8080

(If this is the first time you are running the above command, it downloads a lot of necessary files and stores them in the local Maven repository. This is a one-time operation.) You can now access the web application from a location like “http://localhost:8080/HelloWorld/”. ‘HelloWorld’ is the artifactId that we used when creating the sample application. You can read more about running and deploying applications from Maven to Tomcat web server on Maven Tomcat plugin page.

If Jetty web server is installed on your computer, you can also run your web application in Jetty by running the following command:

# mvn jetty:run

How easy it is to switch the container when you are developing Java web applications with the Maven build tool! You can read more about running and deploying applications from Maven to Jetty web server on Maven 2 Jetty Plugin page.

Setting Up Rails Development Environment on Fedora GNU/Linux

1618 days

by tabrez in General

This is an adaptation to Fedora GNU/Linux platform of my previous posts meant for the Windows & Ubuntu platforms: Setting Up Rails Development Environment on Windows Vista/XP and Setting Up Rails Development Environment on Ubuntu GNU/Linux.

I can think of two different ways in which you might want to set up a development environment for Ruby on Rails on a GNU/Linux machine. One is to download everything outside of the package manager of your distribution i.e. build everything from the source. I am going to cover the second, easier way: how to setup Rails on a Fedora machine using its package manager for the most part. I show below how to setup Ruby, RubyGems, Rails, Mongrel, MySQL, and Git as part of the development stack.

Installing Ruby:

Install the Ruby and related packages as root user:

# yum install ruby ruby-docs ruby-irb ruby-ri ruby-sqlite3
Installing Rubygems

Though it is possible to install Rubygems using the Fedora package manager, not only will you get an old version of rubygems if you do so, it also may not be compatible with the latest version of rails. I strongly recommend you download the source code package of the latest version of rubygems and install it using its setup script:

# cd $HOME
# wget http://rubyforge.org/frs/download.php/45906/rubygems-1.3.1.zip
# tar xvzf rubygems-1.3.1.tgz && cd rubygems-1.3.1
# ruby setup.rb

Remember to download the latest version of rubygems available(currently 1.3.1). You can remove the downloaded tgz archive and the extracted directory after the installation is finished.

#cd $HOME
# rm -r rubygems-1.3.1.tgz rubygems-1.3.1
Installing Rails

Update all the gems(not really needed) and then install the rails gem.

# gem update –&ndashsystem
# gem install rails

To update rails in future, run ‘gem update rails’ command.

Check the versions to confirm installation:

# ruby -v
ruby 1.8.6 (2008-08-11 patchlevel 287) [i386-linux]
# gem -v
1.3.1
# rails -v
Rails 2.2.2

The basic Rails development environment is now installed on your system and you can skip the rest of the post if you are happy with WEBrick as the web server, SQLite as the database server and your favourite text editor/IDE that may be already installed on your system. The following instructions cover installing an alternate web server called Mongrel and MySQL database server and its GUI tools.

Installing Mongrel

Installing the Rails gem also installs the WEBrick web server which is ideally suited for development purposes. Another much recommended web server for Rails development as well as production environment is the Mongrel web server. To install the Mongrel web server, run the following gem command:

# yum install mongrel

After installing Mongrel, Rails automatically starts Mongrel instead of WEBrick web server when you run Rails applications in development mode. (Refer to Mongrel documentation to know more about running Rails applications under Mongrel in production mode.)
Installing MySQL

This step covers the installation of MySQL database server and its GUI tools. Skip this step if you want to use some other database server. Run the following command to install the required mysql packages:

# yum install mysql-server mysql-administrator mysql-gui-tools

One important step during the configuration process is to select a root password(you will need to enter it in the database.yml configuration file of your Rails application).
Source Control

To setup your rails application using git source code management tool, see my other post:
Setting Up Ruby on Rails Projects with Git and Github

You can also install cvs or subversion or other version control software using yum package manager.

# yum install cvs subversion

Now you can create/checkout Rails applications, edit the files using your favourite text editor/IDE and run it under Mongrel. In future, I will try to write about developing Rails applications using integrated development environments like Eclipse and NetBeans.

Setting Up Ruby on Rails Projects with Git and Github

1626 days

by tabrez in General

Git is the favourite source code management tool of the Ruby on Rails community these days. Though GNU/Linux or Mac platforms are generally preferred to Windows by Ruby on Rails as well as git communities, I will show you how you can work with these technologies on Windows platform. I will also show how to host a git public/share repository of a Rails application on the Github free web service. Note that the following information applies to any project, not just Rails.

Refer to my earlier post to see how to install Ruby on Rails on the Windows platform. You can skip some of the later parts if you wish.
Setting Up Rails Development Environment on Windows Vista/XP
Git still has some issues on the Windows platform but for normal usage the msysgit package shouldn’t let you down. Download and install it from its Google Code page.
Download msysgit for Windows

Read the information in last few dialog boxes carefully during the installation and select the settings you prefer. The following screenshots show the settings I have picked when installing msysgit on my system.

Install a separate git shell in which to run the git commands:

I can go to any git initialized directory, right-click a file and say “Git Bash Here” which will save me a lot of ‘cd’ commands:

Git’s built-in SSH support is more than enough for development purposes:

Now you can just go to any Rails directory and run ‘git init’ there to track the files under git.

Start Git Bash shell from the Start Menu.

Go to your Rails directory and run the following commands.

Example session:

# cd hello
# ls
# git init
# git add .

For more git commands that you can use, refer to Git Tutorial. To learn more about how Git handles line ending conversions(especially important to Windows users), refer to gitattributes man page.
If you are working alone on a particular application or you are just interested in maintaining the history of the source code changes locally, then you might prefer just working with in the project directory. If I want to share the changes with friends/colleagues or the world at large, we need a public git repository. Github and Assembla are but only two examples that have good free packages to get started with.
Create a new account on Github.
- Go to github.com
- Click the link “Pricing and Signup” at the top of the page.
- Pick a package(say “Open source” which is free) and click “Signup” button.
- Fill in the information and click “I agree, sign me up!” button if you agree to all the policies.
You need to enter your public SSH key when creating a Github account. If you don’t already have SSH keys generated, you can generate one using git tools. Github website has nice explanation on how to go about setting up SSH key on Windows for Github, so just follow the procedure.

Once you have created the account and are logged in, click the “Create new one” link on the dashboard page, fill in the details and click the “Create Repository” button to create an empty repository on Github.

Now you can push the contents of your Rails directory to the empty git repository that we created on Github in the previous step by running the following command in Git Bash shell:

# cd hello
# git remote add origin g...@github.com:tabrez/hello.git
# git push origin master

Adjust the second command according to your account/project details. Now you can say ‘git push’ from your git tracked directory anytime you want to publish your changes to Github, so that others can pull these changes to their computers and merge them with their local git repository.

Read more about git push.
Read more about Github.