Tomcat and Servlets

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Tomcat and Servlets

• Haifeng Liu

2
Tutorial Overview

• Tomcat Overview
• Setting Up Tomcat
• Running Tomcat
• Installing and Running Servlets
• FAQ?

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Tomcat Overview

• Tomcat is the servlet container
• History
• ASF JServ performance
• Sun Servlet Engine -- specification
• Requirements and Quality Goals
• Strict adherence to Suns JSP/Servlet
  specification, Interoperability, Modifiability,
  Performance, Scalability, High-Availability,
  Security,

--- Jakarta Tomcat
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Setting Up Tomcat on CDF

• Status Installed with user privileges in
• /u/csc309h/lib/jakarta-tomcat-5.0.28
• Step 1 go to website, read instructions
• http//www.cdf.toronto.edu/radu/csc309/guide/tomc
  at.html
• Step 2 download the tar file tomcat.tar.gz
• Step 3 untar it (tar xvz tomcat.tar.gz) and
  copy the files into a working directory which is
  refered as
• e.g. /csc309/
• Inside tomcat
• Bin, conf, logs, webapps, work

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Start Tomcat Server

• Step 1 -- cd /csc309/tomcat/bin
• Step 2 -- Run the script start.sh (may need to
  chmod ax .sh ) ./start.sh
• Step 3 -- Enter the port number. Tomcat will use
  3 ports, the number entered and the next two
  (e.g., if you are assigned port 32000, tomcat
  will use 32000, 32001, 32002).
• Step 4 check /bin/ps -ef grep your_user_id
• Step 5 view http//localhostyour_port_number

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Stop Tomcat Server

• To stop your server, run bin/stop.sh.
• Always remember to stop your server before
  logging off CDF.

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Installing and Compiling Servlets

• Step 1 -- Download the sample files, untar it,
  put into webapps
• Step 2 -- Compile the Java class
• Include the following jar file in your CLASSPATH
  /u/csc309h/lib/tomcat-5.0.27/common/lib/servlet-ap
  i.jar. setenv CLASSPATH CLASSPATH
  /u/csc309h/lib/tomcat-5.0.27/common/lib/servlet-ap
  i.jar
• cd /csc309/tomcat/webapps/csc309/WEB-INF/classes
  
• Compile the servlet javac HelloWorld.java
• Step 3 -- Start Tomcat
• Step 4 Start Browser http//127.0.0.1yourPort
  Number/csc309/servlet/HelloWorld

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HelloWorld Interface
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Adding a Servlet to a Web Application

• Step 1 Download PrintEnv.java and copy it to
  /csc309/tomcat/webapps/csc309/WEB-INF/classes
• Step 2 -- Compile PrintEnv.java
• Step 3 Add the following entries to the
  application descriptor located at
  /csc309/tomcat/webapps/csc309/WEB-INF/web.xml.
• ltservletgt
• ltservlet-namegtPrintEnvlt/servlet-namegt
• ltservlet-classgtPrintEnvlt/servlet-classgt
• lt/servletgt
• ltservlet-mappinggt
• ltservlet-namegtPrintEnvlt/servlet-namegt
• lturl-patterngt/servlet/PrintEnvlt/url-patterngt
• lt/servlet-mappinggt
• Step 4 -- Restart Tomcat
• Step 5 Open browser to http//127.0.0.1yourPort
  Number/csc309/servlet/PrintEnv

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PrintEnv Interface
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Install Tomcat at homeSoftware Prerequisite

• Tomcat Server http//jakarta.apache.org/tomcat/
  
• Eclipse 3.X http//www.eclipse.org/downloads/in
  dex.php
• Sysdeo Eclipse tomcat Launcher plugin
  --http//www.sysdeo.com/eclipse/tomcatPlugin.html
  

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Debugging Servlet

• Compile the servlet in debug mode
• Javac -g HelloWorld.java
• Set the environment variable JPDA_ADDRESS to your
  assigned port number 1000.
• setenv JPDA_ADDRESS 31901 echo JPDA_ADDRESS
• JPDA_ADDRESS31901 export JPDA_ADDRESS
• Start Tomcat in debugging mode using the
  catalina.sh script.
• catalina.sh jpda start
• Start the NerBeans IDE by executing the following
  script /u/csc309h/lib/NetBeans3.6/bin/runide.sh
  

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Debugging Servlet Contd

• Under the Debug menu, click on "Start Session"
  and then on "Attach..., set Host and Port
  number. If everything went well you should see
  the following messages on the "Debugger Console"
  tab in the lower left corner of the window
  Connecting to localhost33000 Connection
  established
• Select the "Runtime" tab on the top left corner
  of the window. Click on "Debugger" and then again
  on "Classes." You should see a list of all the
  classes that are currently loaded into Tomcat.
• Point your browser to http//127.0.0.1yourPortNum
  ber/csc309/servlet/HelloWorld
• Go back to NetBeans, the class HelloWorld should
  have been added to the list of available classes.
  
• Double click on HelloWorld.

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NetBeans Interface
16
Set Netbeans
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Q and A
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Tomcat System
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Directory Structure

• Bin Startup/shutdown scripts and other useful
  files.
• Conf Configuration files, including
  modules.xml, server.xml, and a number of
  apps-ltnamegt.xml.
• Logs event log file for each day
• Webapps web application files
• Work -- intermediate files (such as compiled JSP
  files) during its work. If you delete this
  directory while Tomcat is running you will not be
  able to execute JSP pages!

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Sysdeo Eclipse Tomcat Launcher plugin

• Starting, stopping and restarting Tomcat 4.x,
  5.0.x, 3.3
• Registering Tomcat process to Eclipse debugger
• Creating a WAR project (wizard can update
  server.xml file)
• Adding Java Projects to Tomcat classpath
• Setting Tomcat JVM parameters, classpath and
  bootclasspath
• Exporting a Tomcat project to a WAR File
• Choosing Tomcat configuration file
• Capability to use a special Tomcat classloader to
  have classes in several java projects loaded at
  the same classloader level than classes in a
  Tomcat project, see readmeDevLoader.html (Thanks
  Martin Kahr)

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Setup Tomcat

• Enable tomcat
• Go to the menu "Window-gt Preferences"
• go to "Tomcat" and select your Tomcat version
• adjust the field "Tomcat Home" to point to the
  install directory
• Add a new user
• scroll down the menu point "Tomcat" and click the
  item "Tomcat Manager App"
• add a username and a password
• click on "Add user to tomcat-users.xml"
• Test Start Tomcat Server

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HelloWorld Example

• Open a new project
• select "Tomcat Project"..., click Next button
• call our new project "Hello World"
• adjust URI http//localhost8080/HelloWorld/hello
  
• create a new class named HelloServlet in the
  directory WEB-INF/src
• create the file web.xml in the directory WEB-INF
  (Note not in WEB-INF/src!!!)
• Start browser "http//localhost8080/HelloWorld/he
  llo"

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HelloServlet

• import java.io.
• import javax.servlet.http.
• import javax.servlet.
• public class HelloServlet extends HttpServlet
  public void doGet (HttpServletRequest
  req,HttpServletResponse res) throws
  ServletException, IOException PrintWriter out
  res.getWriter() out.println("Hello, Brave new
  World!") out.close()

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Web.xml

• lt!DOCTYPE web-app PUBLIC'-//Sun Microsystems,
  Inc.//DTD Web Application 2.3//EN''http//java.su
  n.com/dtd/web-app_2_3.dtd'gt
• ltweb-appgtltservletgt ltservlet-namegthellolt/servlet-
  namegt ltservlet-classgtHelloServletlt/servlet-classgt
  lt/servletgt
• ltservlet-mappinggt ltservlet-namegthellolt/servle
  t-namegt lturl-patterngt/hellolt/url-patterngtlt/servl
  et-mappinggt
• lt/web-appgt