Installing JDK and Tomcat Vijayan Sugumaran Department of DIS Oakland University

Downloading JDK  JDK 6 (J2SE v1.6.0_03) installer can be downloaded from the following url:  Click on the Download button  Click on Accept (license agreement) and continue  Click on the link for online installation:  Windows Online Installation, Multi-language  Run the installer  Accept all the default settings. It will create a new directory (C:\Program Files\Java\jdk1.6.0_03) and there will be a subdirectory called “bin” which contains all the jdk tools (javac, java, etc.). There will also be another subdirectory called “lib” that contains the.jar files

Setting Environment Variables  In order to access the java binary files from any directory, we should set the PATH environment variable  To access.class files from other locations, we need to set the CLASSPATH variable.  The CLASSPATH variable can also indicate where to look for.jar files

Setting Path and Classpath  Right mouse click on “My Computer” and select the “Properties” option  The system properties panel will pop up. Click on the “Advanced” tab.  Click on the “Environment Variables” button  If the Path and Classpath variables are already defined, then you can add values at the end by clicking on the “Edit” button.  The directories are separated by semicolon  If the variables don’t exist, then you can create them by clicking on the “New” button, and enter the values for those variables (see next slide)  The first value for the classpath variable should be “.;” that indicates current directory

System Properties Panel

Downloading and Installing Tomcat  Download url:  Scroll down to the Binary Distributions section and click on the zip link under Core to download tomcat  The downloaded zip file needs to be unzipped. You can put the contents under Program Files or anywhere else you like.

Configuring Tomcat  Make sure the “JAVA_HOME” environment variable exists. If not, create this variable and set it to C:\Program Files\Java\jdk1.6.0_03 (or the directory where jdk resides)  For now, leave the port to 8080 (you can change it to another port number later in the server.xml file)  Turn on Servlet Reloading  Open the context.xml file (C:\Program Files\apache-tomcat \conf\context.xml ) using notepad  In the context.xml file, change to (it is case sensitive) 

Configuring Tomcat (Contd)  Enable the Invoker Servlet  Uncomment the servlet and servlet-mapping elements in the web.xml file (C:\Program Files\apache-tomcat \conf\web.xml)  <!-- (remove this line)   invoker   org.apache.catalina.servlets.InvokerServlet   debug  0   2   --> (remove this line)  <!-- (remove this line)   invoker  /servlet/*   --> (remove this line)

Configuring Tomcat (contd)  Turn on Directory Listings when there is no welcome-file (optional)  Edit the conf/web.xml file as follows default org.apache.catalina.servlets.DefaultServlet debug 0 listings true 1

Test the Server  Start the server  Click on C:\Program Files\apache-tomcat /bin/startup.bat  Open a browser window and type the url:  The Tomcat page should show up  Try some simple HTML and JSP Pages  Try executing the servlet examples  Need to set up a development environment so that you can compile your own servlets. They need to be in a specific locaiton.

Directory Structure of Web Application

Setting up the Application Directory Structure  Create a directory for each application within the webapps (C:\Program Files\apache- tomcat \webapps) directory and the necessary sub directories within it.  Example:  Create a directory called “HelloApp” for the “hello world” application within the webapps directory  Within HelloApp, create a subdirectory called “WEB-INF”  Within WEB-INF, create a subdirectory called “classes”  The compiled servlets have to reside in the “classes” directory

Creating, Compiling & Executing a Servlet  Type the code for the Hello servlet using notepad  Save it as Hello.java in the following directory: C:\Program Files\apache-tomcat \webapps\HelloApp\WEB-INF\classes  Add the path for the servlet-api.jar and jsp- api.jar files to the classpath variable  (C:\Program Files\apache-tomcat \lib\servlet-api.jar; C:\Program Files\apache-tomcat \lib\jsp-api.jar; )  Compile the Hello.java file using javac  The Hello.class file will be created and it should also reside in the same classes directory  Executing the Hello servlet

Creating a New Web Application  Steps to create a new web application called “anotherapp”  Create the appropriate directory structure  Restart Tomcat  Add one or more servlets to the application  Test the servlets  To control the behavior of this application add web.xml file to the WEB-INF directory  If a web.xml file is not provided for this application, the install_dir/conf/web.xml file will be used

Creating the Directory Structure (Review)  Create a folder called “anotherapp” (or any other name you choose) within the install_dir/webapps folder  Create the “WEB-INF” folder within the “myapps” folder  Create the “classes” folder within the “WEB-INF” folder  For now, make sure that you don’t have web.xml file within the WEB-INF directory

Remaining Steps  Restart Tomcat  Add one or more servlets to the “anotherapp” application  Create the servlet source file (.java file) in the install_dir/webapps/anotherapp/WEB-INF/classes directory  Compile the source file using javac  Alternatively, you can put the source file(s) anywhere you want, compile them, and then move the.class files into the install_dir/webapps/anotherapp/WEB-INF/classes directory  Test the servlet (say you created Hello.class) 

Deployment Descriptor File – WEB-INF/web.xml  The install_dir/conf/web.xml file controls the behavior of all the web applications that are under the webapps directory  If you want a particular web application to behave differently, then you add the web.xml file within the WEB-INF directory  It is not absolutely necessary that you should have the web.xml file for the application  Among other things, the web.xml file may contain the values of parameters that would be used during servlet initialization (calling the init() method)