Apache Tomcat (Version 6.0)

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Apache Tomcat(Version 6.0)

• Presented by
• Vishal Rajpurohit

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What is Apache Tomcat?

• Apache is the most common HTTP Web Server on the
  Internet. It is the Web server used at
  http//web.njit.edu
• The Tomcat server is a Java-based Web Application
  container which is used to run Servlet and Java
  Server Pages (JSP) Web applications.
• Tomcat has become the reference implementation
  for both the Java Servlets and Java Server Pages
  specifications.
• Tomcat was chosen to be the official Sun Web
  Component (JSP/Servlet ) Container Reference
  Implementation.

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What is Apache Tomcat? Contd.

• Apache Tomcat is used to serve Java Servlets and
  Java Server Pages. It's a complex piece of
  software and though the documentation is very
  comprehensive, it helps to have a good reference
  work to hand.
• It is an open source Java Servlet application
  server used to deploy Java applications after
  they are built with JSP and Servlets. It can be
  used as a stand-alone product or it can be
  integrated with the Apache server.

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What is a container?

• Containers are the interface between a component
  and the low-level platform-specific functionality
  that supports the component.
• Before a Web, enterprise bean, or application
  client component can be executed, it must be
  assembled into a J2EE module and deployed into
  its container.

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J2EE Containers (Server)

• J2EE server
• The runtime portion of a J2EE product. A
  J2EE server provides EJB and Web containers.
• Enterprise JavaBeans (EJB) container
• Manages the execution of enterprise beans
  for J2EE applications. Enterprise beans and their
  container run on the J2EE server.
• Web container
• Manages the execution of JSP page and
  servlet components for J2EE applications. Web
  components and their container run on the J2EE
  server.

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J2EE Containers (Client)

• Application client container
• Manages the execution of application client
  components. Application clients and their
  container run on the client.
• Applet container
• Manages the execution of applets. Consists
  of a Web browser and Java Plug-in running on the
  client together.

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J2EE Server and Containers
Web Server (Apache)
Client
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Working environments

• Java is already installed on PCs in the NJIT PC
  labs and the Solaris and Linux labs on the second
  floor of GITC. Tomcat is also installed on the
  Solaris machines. It is recommended that all work
  with Tomcat be done on AFS31 through AFS35.
• The installation guides on the following slides
  are for your own computers.

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Initial Setup

• The Java Software Development Kit (JDK) is
  aimed at Java developers. It consists of Sun's
  Java Runtime Environment bundled with programming
  tools. Java Runtime Environment (JRE) is the
  software required to run any application deployed
  on Java platform.
• Download J2SE Runtime Environment
• Install the JRE according to the instructions
  included with the release.

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Installation of Apache Tomcat

• Initiate the download of Tomcat from the site
• http//tomcat.apache.org/
• View the corresponding documentation and setup
  for help in running on various platform and
  requirements.
• After downloading follow the instructions to
  start installation.

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Start Up Tomcat

• Tomcat can be started by executing the following
  commands
• CATALINA_HOME\bin\startup.bat
  (Windows)
• CATALINA_HOME/bin/startup.sh
  (Unix)
• After startup, the default web applications
  included with Tomcat will be available by
  visiting
• http//localhost8080/

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Link Details
http//localhost8080/myapp/chapter01/sample00.htm
l
Can OMIT if using ROOT as default
Server is local
Path to file
Listens on port 8080
protocol is http
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Shut Down Tomcat

• Tomcat can be shut down by executing the
  following command
• CATALINA_HOME\bin\shutdown
  (Windows)
• CATALINA_HOME/bin/shutdown.sh (Unix)

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Enabling SSI and CGI support

• SSI and CGI are disabled by default for
  security reasons to enable them
• To enable and configure CGI support, please see
  the cgi-howto.html page.
• To enable and configue SSI support, please see
  the ssi-howto.html page.

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Security Managers URL

• In order to grant security permissions to
  JARs located inside the web application
  repository, use URLs of of the following format
  in your policy file
• filecatalina.home/webapps/examples/WEB-INF
  /lib/driver.jar

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Enabling invoker servlet(NJIT is non-standard)

• Starting with Tomcat 4.1.12, the invoker servlet
  is no longer available by default in all webapps.
  Enabling it for all webapps is possible by
  editing CATALINA_HOME/conf/web.xml to uncomment
  the "/servlet/" servlet-mapping definition.
• Using the invoker servlet in a production
  environment is not recommended and is
  unsupported. More details are available on the
  Tomcat FAQ at
• http//tomcat.apache.org/faq/misc.htmli
  nvoker.
• WARNING! On NJIT Systems, the invoker servlet
  is in use, and needs to be maintained if you edit
  your web.xml. A URL must be in the form
  http//web.njit.edu/ltucidgt/servlet/ltclassnamegt
  for the servlet to be found and executed by
  Tomcat.

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UCS at NJIT

• Apache Tomcat is installed on UCS and servlets
  can be run after configuration of your account.
• Basic information will be available from link
• http//web.njit.edu/all_topics/Servers/Tomcat
  /
• Changes to servlets are seen immediately. The
  first time you set up Tomcat, servlets are
  visible only after the NJIT server is restarted
  which is done once a day at 600 AM.
• As of 03/2008 Apache is running on afs31-afs35.

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Any other web server using port 8080

• This happens usually when any other web
  server (or any process) has laid claim to port
  8080 and this one is the default HTTP port that
  Tomcat attempts to bind to at startup. So for
  changing this, open the file
• CATALINA_HOME/conf/server.xml
• and search for '8080'. Change it to a port
  that isn't in use, and is greater than 1024, as
  ports less than or equal 1024 require superuser
  (root) access to bind under UNIX. Restart Tomcat.
  Be sure that you replace the "8080 in the URL
  you're using to access Tomcat. If you change the
  port to 1977, you would request the URL
  http//localhost1977/ in your browser.

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Out of environment space error

• An "out of environment space" error
• This happens when running the batch files in
  Windows 95, 98, or ME operating systems.
  Right-click on the STARTUP.BAT and SHUTDOWN.BAT
  files. Click on "Properties", then on the
  "Memory" tab. For the "Initial environment"
  field, enter in something like 4096. After you
  click apply, Windows will create shortcuts which
  you can use to start and stop the container.

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The 'localhost' machine isn't found error

• The 'localhost' machine isn't found.
• This could happen if you're behind a proxy. If
  that's the case, make sure the proxy
  configuration for your browser knows that you
  shouldn't be going through the proxy to access
  the "localhost". In Netscape, this is under
  Edit/Preferences -gt Advanced/Proxies, and in
  Internet Explorer, Tools -gt Internet Options -gt
  Connections -gt LAN Settings.

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Apache Tomcat Updates

• The latest version of Apache Tomcat changes
  regularly so keep updated by visiting the link
• http//tomcat.apache.org/

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Advantages of Tomcat

• 1) It is an open source application server
• 2) It is a light weight server (no EJB)
• 3) It is easily configured with apache and IIS
• 4) Very stable on Unix systems
• 5) Good documentation online
• 6) Java Sun compliant
• 7) Does not require a lot of memory at startup
• 8) It is free, yet high quality!

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References
http//tomcat.apache.org http//java.sun.com http
//jakarta.apache.org/