J2EE

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Component Technologies:
1. Jsp
2. Servlets
3. ejb, jms, jca
4. misc: JNDI, JTS, JavaMail. Java Corba, JCA,

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   from Web Services/Webapps
5. WebApp Frameworks: MVC, Struts, JSF, WAF
6. JAXP, JAXR, JAX-RPO, SAAJ

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   from webapps: App Servers
7. Weblogic, Websphere

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   from j2se
8. jdbc, corba (ejb predecessor) (cf. j2se notes)

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I. JSPs

a. syntax

• Directives
  1. <%@ page ... %> ; <%@ page language="java" %> - always 1st line ofall jsps
  2. <%@ include ... %>
  3. <%@ taglib ... %> - custom tags, <%@ taglib uri="WEB-INF/lib/tag_lib_name.tld" prefix="prefix_name" %>
• Declaration <%! private int i; %>
• Scriptlet <% ... %>
• Expressions <= i %>
• Beans <jsp:useBean id="id_bean" class="xPackage.xClass" scope="session" /> ... <% id_bean.f() %>

b. implicit objects

Implicit object	Description
request	Represents the client’s request. An implementation of javax.servlet.http.HttpServletRequest
response	Represents the JSP page’s response. An implementation of javax.servlet.http.HttpServletResponse
pageContext	Represents the objects and attributes associated with a page. A subclass of javax.servlet.http.pageContext
session	Represents the session associated with the request. An implementation of javax.servlet.http.HttpSession
application	Represents the application associated with the request. An implementation of javax.servlet.ServletContext

• session
  • session.setAttribute("xattribute", i)
  • session.getAttribute("xattribute")

xProject
 |
 +- build.xml
 +- f.jsp 
 +- WEB-INF
      |
      +- web.xml 
      +- f.tld
      +- classes
           +- com
               +- dupont
                    +- texas
                         +-- f.java 

<?xml version="1.0" encoding="ISO-8859-1"?>

<!DOCTYPE web-app
  PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN"
  "http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">

<web-app>
 <taglib>
    <taglib-uri> /WEB-INF/tagExampleLib.tld </taglib-uri> 
    <taglib-location> /WEB-INF/tagExampleLib.tld </taglib-location> 
  </taglib>
</web-app>

II. Servlets Servlets are pure Java objects that generate HTML by writing it to a stream

I. ejb

a. servlets

a. ant

• > ant = > ant default = > ant compile; ant war
• > ant compile; ant war (compile srcs, assemble j2ee module files + war file)
• ant default; ant deploy
• > ant -buildfile f (alt.buildfile, deflt. build.xml)
• ant compile; ant dist; ant deploy (compile, make distrib war file, cp to dir)
• erase WEB-INF/classes/* then again ant to force changes to new files to take effect; ant recreates the folder struct

<project name="MyStrutsProject" default="dist" basedir=".">

  <description> struts ant buildfile </description>

  <property name="xsrc" location="WEB-INF/src"/>  <!-- set global properties for this build -->
  <property name="xbuild" location="WEB-INF/classes"/>
  <property name="xdist"  location="WEB-INF/dist"/>

<target name="init">
  <tstamp/> <!-- create time stamp -->
  <mkdir dir="${xbuild}"/>
</target>

<target name="compile" depends="init" description="compile srcs">
   <!-- Compile the java code from ${src} into ${build} -->
   <javac srcdir="${xsrc}"
     destdir="${xbuild}"
     classpath="WEB-INF/lib"/>
</target>

<target name="dist" depends="compile" description="make war">
   <war warfile="f-${DSTAMP}.war" webxml="web.xml">
     <fileset dir=".">  <!-- include all JSPs in root level -->
       <include name="*.jsp"/>
       <include name="*.xml"/>
     </fileset>

     <lib dir="./WEB-INF/lib">
        <include name="*.jar"/>
     </lib>

     <!-- include all tag libraries in WEB-INF,
          but not web.xml (that's handled separately) -->
     <webinf dir="WEB-INF/">
       <include name="*.tld"/>
     </webinf>

     <classes dir="./WEB-INF/classes"/>  <!-- include all compiled classes -->
   </war>
 </target>

 <target name="deploy">
   <!-- Copy the war file to the JBoss deploy directory -->
   <copy file="f.war" todir="."/>
 </target>

 <target name="all" depends="dist,deploy"/>

</project>

References