javaBootcampNoEclipse/docs/javaBootcampNoEclipse.org

#+TITLE: Dude! Where's my Eclipse!?
#+DATE: [2017-08-14 Mon]
#+AUTHOR: Éibhear Ó hAnluain, Version 1
#+EMAIL: eibhear.ohanluain@version1.com
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#+OPTIONS: tags:t tasks:t tex:t timestamp:t toc:t todo:t |:t
#+CREATOR: Emacs 24.5.1 (Org mode 9.0)
#+DESCRIPTION: A java bootcamp module on building an app for tomcat with just the command-line
#+EXCLUDE_TAGS: noexport
#+KEYWORDS:
#+LANGUAGE: en
#+SELECT_TAGS: export

* Dude! Where's my Eclipse

** Pre-requisites
   You will need a linux server with the following installed:
   - tomcat :: This demo was prepare with tomcat-8.
   - tomcat manager :: Used for deploying the your built application
   - A web browser :: for accessing the tomcat manager
   - git :: to access the project
   - a text editor :: to fix any bugs you find (*Not* =eclipse=,
                      because that's the whole point.)
   - java 8 JDK :: to build code
   If you develop on one machine and deploy to the other, then
   *tomcat* and *tomcat manager* are to be on the system you're
   deploying to, and the rest where you're developing.

   If your development environment is not on the same server as the
   *tomcat* instance, you'll need a copy of the file
   =tomcat8-servlet-api.jar= on the same system as your java code.

** Setting up
   0. [@0] All commands assume a Linux environment. =${HOME}= refers
      to the home directory of the user, and =${DEV_HOME}= refers to
      where the git repository has been cloned to.
   1. Get the code
      : git clone https://gitlab.com/eibhear/javaBootcampNoEclipse.git
      The repository is now in =${DEV_HOME}=. Change into it:
      : export DEV_HOME=$(pwd)/javaBootcampNoEclipse
      : cd ${DEV_HOME}
   2. Make sure you're at the starting point:
      : git checkout lesson-1

** Lesson 1 -- compile the code.

*** Starting point
    A clean git working area

*** Goal
    Java files compiled into class files

*** Steps
    0. [@0] Confirm you can access the java compiler:
       : javac -version
       If this doesn't result in a message like =javac 1.8.0_141=,
       you'll need to find where =javac= installed and place it on
       your =${PATH}=.
    1. Change to where the code is:
       : cd ${DEV_HOME}/source/java/org/gibiris/javaBootcampNoEclipse
    2. Compile the files:
       : javac *.java
    3. Check the errors. If you see the message =error: package
       javax.servlet does not exist=, then look at your =CLASSPATH=
       setting, as dependend libraries are missing.
    4. Fix your =CLASSPATH= and compile the java files:
       : export CLASSPATH=/usr/share/java/tomcat8-servlet-api.jar:${CLASSPATH}
       : javac *.java
    5. If the successful, you will have the following additional files:
       : ${DEV_HOME}/source/java/org/gibiris/javaBootcampNoEclipse/MyHelloWorldBean.class
       : ${DEV_HOME}/source/java/org/gibiris/javaBootcampNoEclipse/MyHelloWorldServlet.class
       If this is the case, move on to lesson 2:
       : git checkout lesson-2

** Lesson 2 -- build the jar file

*** Starting point
    A clean git working area with two additional class files

*** Goal
    Class files archived into a jar file

*** Steps
    1. Decide whether you want to include the source (=*.java=) files
       in the jar file
    2. Determine other files to be included in the jar file
       (e.g. config files, property files, etc.)
    3. Change to the top-level of the package in the source:
       : cd ${DEV_HOME}/source/java
       Create the =lib/= directory to take the jar file:
       : mkdir -pv ../lib
       If you're *not* including the source files in the jar:
       : jar cvf ../lib/javaBootcampNoEclipse.jar org/gibiris/javaBootcampNoEclipse/*.class
       If you *are* including the source files in the jar:
       : jar cvf ../lib/javaBootcampNoEclipse.jar org/gibiris/javaBootcampNoEclipse/*
    4. If the successful, you will now have a new file:
       : ${DEV_HOME}/source/lib/javaBootcampNoEclipse.jar
       If this is the case, move on to lesson 3:
       : git checkout lesson-3

** Lesson 3 -- build the war file

*** Starting point
    A clean git working area with two additional class files and one
    additional jar file.

*** Goal
    A deployable war file

*** Steps
    0. [@0] Review the following:
       - http://tomcat.apache.org/tomcat-8.0-doc/appdev/deployment.html
         to understand the structure of the =war= file and the
         =web.xml= file
       - =${DEV_HOME}/source/res/web.xml= to understand how this
         application is to be used.
    1. Create an empty directory in =${DEV_HOME}= called =webapp=,
       then its directory structure and then change into it:
       : mkdir -vp ${DEV_HOME}/webapp
       : mkdir -vp ${DEV_HOME}/webapp/WEB-INF/lib
       : cd ${DEV_HOME}/webapp
    2. Copy in the jsps:
       : cp -rv ${DEV_HOME}/source/jsps/* ${DEV_HOME}/webapp
    3. Copy in the jar file:
       : cp -rv ${DEV_HOME}/source/lib/javaBootcampNoEclipse.jar ${DEV_HOME}/webapp/WEB-INF/lib
    4. Copy in the =web.xml= file:
       : cp -rv ${DEV_HOME}/source/res/web.xml ${DEV_HOME}/webapp/WEB-INF
    5. Create the war file:
       : jar cvf ${DEV_HOME}/source/lib/javaBootcampNoEclipse.war *
    6. If this was successful you will now have a new file:
       : ${DEV_HOME}/source/lib/javaBootcampNoEclipse.war
       If this is the case, remove the direcory =${DEV_HOME}/webapp=
       and move on to lesson 4:
       : rm -fr ${DEV_HOME}/webapp
       : git checkout lesson-4

** Lesson 4 -- deploy and test

*** Starting point
    A clean working area with two additional class files, one
    additional jar file and one additional war file.

*** Goal
    A deployed, working application

*** Steps
    0. [@0] Some pre-steps
       - If this isn't the first time to deploy, be sure to /undeploy/
         the previous version of the application.
    1. Navigate to =http://server:8080/manager=
    2. Go to the /WAR file to deploy/ section and use the /Browse.../
       button to select the war file to deploy.
    3. Press the /Deploy/ button. If successful, you'll see your
       application shown in the list.
    4. Go to =http://server:8080/javaBootcampNoEclipse= to access your
       app.
    5. Test the application. If all is well, move on to lesson 5:
       : git checkout lesson-5

** Lesson 5 -- Add new functionality

*** Starting point
    A clean working brought up to date to include the two new files:
    =${DEV_HOME}/source/java/org/gibiris/javaBootcampNoEclipse/AstroFun.java=
    and =${DEV_HOME}/source/lib/AstroLib-1.1.5ws.jar=, and an update
    to
    =${DEV_HOME}/source/java/org/gibiris/javaBootcampNoEclipse/MyHelloWorldServlet.java=.

*** Goal
    A working, updated application deployed to tomcat

*** Steps
    0. [@0] Pre-steps
       - Make sure your environment is set up as per the previous lessons:
         + =DEV_HOME= is set to where the git repository is cloned to
         + =CLASSPATH= contains =tomcat8-servlet-api.jar=
       - Clean out the working area if there are unnecessary/unwanted files:
         : rm -vf ${DEV_HOME}/source/java/org/gibiris/javaBootcampNoEclipse/*.class
         : rm -vf ${DEV_HOME}/source/lib/javaBootcampNoEclipse.?ar
         : rm -vfr ${DEV_HOME}/webapp
       - Review the changes that have been applied to the working area
    1. Compile the java files (including the new java file) as per
       Lesson 1.

       Does it compile? If not, why. Two hints:
       - there was a new jar file introduced to the repository
       - there's a bug in the package specification in the new java
         file. Looking closely at the branches of this git repository,
         you might even find a fix for it.

    2. Build the jar file as per Lesson 2 (except, this time, the
       =lib= directory exists already).

    3. Build the war file as per Lesson 3.

    4. Deploy the updated application as per lesson 4. You will need
       to undeploy the previous version first.

       Does it deploy? Why not? (Hint: there was a new jar file
       introduced to the repository)

    5. Fix the new bug, undeploy the bad application and deploy the
       corrected one.